Merge remote-tracking branch 'origin/master' into xjt/generated-docs-zh-translation-apply

# Conflicts: # .agents/notes/implemented/feature/2026-08-07-default-model-follows-the-picker.i18n.yaml # .agents/notes/implemented/feature/2026-08-07-default-model-follows-the-picker.zh.md # docs/architecture.i18n.yaml # docs/architecture.zh.md # docs/user/guide/providers.i18n.yaml # docs/user/guide/providers.zh.md # docs/user/guide/quickstart.i18n.yaml # docs/user/guide/quickstart.zh.md # packages/boot/app-boot/README.i18n.yaml # packages/boot/app-boot/README.zh.md # packages/bundle/headless/README.i18n.yaml # packages/bundle/headless/README.zh.md
2026-08-09 15:17:35 +08:00
parent c12bcc6f4b 8c124f84b6
commit a0d48c9c87
169 changed files with 1618 additions and 1086 deletions
--- a/packages/acp/acp/src/index.ts
+++ b/packages/acp/acp/src/index.ts
@@ -66,7 +66,7 @@ function internalError(detail: string): RequestError {
  return RequestError.internalError(undefined, detail)
 }

-/** Plugin config: the provider/model target used for each ACP-created agent. */
+/** Plugin config: the provider/model selection used for each ACP-created agent. */
 export interface AcpConfig {
  /** Provider route for created agents. */
  provider?: string
@@ -100,7 +100,7 @@ interface SessionRecord {
 /**
 * Mount the automation-only ACP server.
 * @param ctx - Cordis context carrying the agent factory and session events.
- * @param config - Initial provider/model target and optional test transport.
+ * @param config - Initial provider/model selection and optional test transport.
 */
 export function apply(ctx: Context, config: AcpConfig): void {
  // ACP handlers execute outside this plugin's injection scope, so capture the
--- a/packages/boot/app-boot/README.i18n.yaml
+++ b/packages/boot/app-boot/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/boot/app-boot/README.md
-README.md: c256b89288e3e384c1dd3e64629a06d7cfef31f6
-README.zh.md: 6ff915c618f636f05f1f8591433feb3aef9151a8
+README.md: c060e99acb8cc40b8de92806727eea9e3723b7d2
+README.zh.md: 006eb0f0705cf4904afe90b7d4ffbeee347b4110
--- a/packages/boot/app-boot/README.md
+++ b/packages/boot/app-boot/README.md
@@ -33,7 +33,7 @@ This package carries no loader hooks and no dev-mode surface. The [`dsh` app](..

 ## Profiles

-A profile is a directory under `$DSH_HOME/profiles/<name>` (the Harness home resolves through [`resolveDshHome`](../../util/paths/README.md): `$DSH_HOME`, else `~/.dsh`) holding a `package.json` — out-of-tree plugin `dependencies` plus the profile manifest `dsh.profile` with its ordered `bundles` layer list — and the user's own `cordis.patch.yml`. A bundle is an npm package whose manifest declares `"dsh": { "bundle": { "patch": "./cordis.patch.yml" } }`; `loadProfile` resolves each `dsh.profile.bundles` name two-anchored (the dsh installation first, then the profile directory) and fails loud on a listed package without a bundle declaration. `composeEntries` applies patch layers over an empty entry list through the include's own `applyEntryPatches`, so composition, flag derivation, and config dumps can never drift from what boots. `healProfilesModuleFallback` maintains the flat `$DSH_HOME/profiles/node_modules` directory — one symlink per package the installation's app and bundles depend on — so bare plugin names in any profile resolve through Node's ordinary parent-walk without pnpm ever managing in-box packages. `PROFILE_TEMPLATES` (`web`, `headless`) auto-initialize on first use; other names fail loud until `initProfile` creates them (the `dsh plugin` path).
+A profile is a directory under `$DSH_HOME/profiles/<name>` (the Harness home resolves through [`resolveDshHome`](../../util/paths/README.md): `$DSH_HOME`, else `~/.dsh`) holding a `package.json` — out-of-tree plugin `dependencies` plus the profile manifest `dsh.profile` with its ordered `bundles` layer list — and the user's own `cordis.patch.yml`. A bundle is an npm package whose manifest declares `"dsh": { "bundle": { "patch": "./cordis.patch.yml" } }`; `loadProfile` resolves each `dsh.profile.bundles` name two-anchored (the dsh installation first, then the profile directory) and fails loud on a listed package without a bundle declaration. `composeEntries` applies patch layers over an empty entry list through the include's own `applyEntryPatches`, so composition, flag derivation, and config dumps cannot drift from what boots. `healProfilesModuleFallback` maintains the flat `$DSH_HOME/profiles/node_modules` directory — one symlink per package the installation's app and bundles depend on — so bare plugin names in any profile resolve through Node's ordinary parent-walk without pnpm managing in-box packages. `PROFILE_TEMPLATES` (`web`, `headless`) auto-initialize on first use; other names fail loud until `initProfile` creates them (the `dsh plugin` path). `loadProfile` normalizes an exact installation-owned bundle tuple to its shipped template while preserving every other manifest field; any extra, missing, or reordered entry makes the list user-owned and leaves it unchanged.

 User-level machine-local preferences also live in the Harness home:

--- a/packages/boot/app-boot/README.zh.md
+++ b/packages/boot/app-boot/README.zh.md
@@ -33,7 +33,7 @@ Loader 并发挂载各个条目，因此当其他环节失败时，某个界面

 ## Profiles

-profile 是位于 `$DSH_HOME/profiles/<name>` 下的目录（Harness home 由 [`resolveDshHome`](../../util/paths/README.md) 解析：先取 `$DSH_HOME`，否则取 `~/.dsh`），其中包含一个 `package.json`（树外插件 `dependencies`，加上 profile manifest `dsh.profile` 及其有序的 `bundles` 层列表）和用户自己的 `cordis.patch.yml`。组合包是在 manifest 中声明 `"dsh": { "bundle": { "patch": "./cordis.patch.yml" } }` 的 npm 包；`loadProfile` 以双锚点解析每个 `dsh.profile.bundles` 名称（先从 dsh 安装目录，再从 profile 目录），列出的包若没有组合包声明则明确报错。`composeEntries` 通过 include 自己的 `applyEntryPatches` 在空条目列表之上应用各 patch 层，因此组合、标志推导和配置 dump 绝不会与实际启动内容发生偏离。`healProfilesModuleFallback` 维护扁平的 `$DSH_HOME/profiles/node_modules` 目录（安装目录的应用与各组合包依赖的每个包对应一个符号链接），使任意 profile 中的裸插件名都能经 Node 常规的逐级向上查找解析，而 pnpm 从不管理随安装内置的包。`PROFILE_TEMPLATES`（`web`、`headless`）在首次使用时自动初始化；其他名称在 `initProfile` 创建之前都会明确报错（即 `dsh plugin` 路径）。
+profile 是位于 `$DSH_HOME/profiles/<name>` 下的目录（Harness home 由 [`resolveDshHome`](../../util/paths/README.md) 解析：先取 `$DSH_HOME`，否则取 `~/.dsh`），其中包含一个 `package.json`（树外插件 `dependencies`，加上 profile manifest `dsh.profile` 及其有序的 `bundles` 层列表）和用户自己的 `cordis.patch.yml`。组合包是在 manifest 中声明 `"dsh": { "bundle": { "patch": "./cordis.patch.yml" } }` 的 npm 包；`loadProfile` 以双锚点解析每个 `dsh.profile.bundles` 名称（先从 dsh 安装目录，再从 profile 目录），列出的包若没有组合包声明则明确报错。`composeEntries` 通过 include 自己的 `applyEntryPatches` 在空条目列表之上应用各 patch 层，因此组合、标志推导和配置 dump 绝不会与实际启动内容发生偏离。`healProfilesModuleFallback` 维护扁平的 `$DSH_HOME/profiles/node_modules` 目录（安装目录的应用与各组合包依赖的每个包对应一个符号链接），使任意 profile 中的裸插件名都能经 Node 常规的逐级向上查找解析，而 pnpm 从不管理随安装内置的包。`PROFILE_TEMPLATES`（`web`、`headless`）在首次使用时自动初始化；其他名称在 `initProfile` 创建之前都会明确报错（即 `dsh plugin` 路径）。`loadProfile` 会将与安装自有组合包元组完全一致的列表规范化为随发行版交付的模板，同时保留 manifest 中其他所有字段；一旦条目有任何额外、缺失或重排，该列表就归用户所有并保持不变。

 用户级的机器本地偏好同样位于 Harness home 中：

--- a/packages/boot/app-boot/src/profile.ts
+++ b/packages/boot/app-boot/src/profile.ts
@@ -114,6 +114,11 @@ export function resolveProfileDir(name: string, home: string = resolveDshHome())
 /** The shipped profile templates auto-initialized on first use, by name. */
 export const PROFILE_TEMPLATES: Record<string, readonly string[]> = {
  web: ['@deepseek-ai/dsh-base', '@deepseek-ai/dsh-web-app'],
+  headless: ['@deepseek-ai/dsh-base', '@deepseek-ai/dsh-headless'],
+}
+
+/** Installation-owned bundle tuples normalized to the shipped template. */
+const INSTALLATION_OWNED_PROFILE_TUPLES: Record<string, readonly string[]> = {
  headless: ['@deepseek-ai/dsh-base', '@deepseek-ai/dsh-web-app', '@deepseek-ai/dsh-headless'],
 }

@@ -279,6 +284,32 @@ export function writeProfileManifest(dir: string, manifest: ProfileManifest): vo
  writeFileSync(join(dir, 'package.json'), JSON.stringify(manifest, undefined, 2) + '\n')
 }

+/** Return whether two bundle lists have the same values in the same order. */
+function sameBundles(left: readonly string[], right: readonly string[]): boolean {
+  return left.length === right.length && left.every((value, index) => value === right[index])
+}
+
+/**
+ * Normalize an exact installation-owned bundle tuple to its shipped template
+ * while preserving every other manifest field. Any other list is user-owned.
+ */
+function normalizeShippedProfile(name: string, dir: string, manifest: ProfileManifest): ProfileManifest {
+  const installationOwned = INSTALLATION_OWNED_PROFILE_TUPLES[name]
+  const current = PROFILE_TEMPLATES[name]
+  const bundles = manifest.dsh?.profile?.bundles
+  if (installationOwned === undefined || current === undefined || bundles === undefined
+    || !sameBundles(bundles, installationOwned)) return manifest
+  const normalized: ProfileManifest = {
+    ...manifest,
+    dsh: {
+      ...manifest.dsh,
+      profile: { ...manifest.dsh?.profile, bundles: [...current] },
+    },
+  }
+  writeProfileManifest(dir, normalized)
+  return normalized
+}
+
 /**
 * Resolve a package's root directory from one anchor without depending on the
 * package exporting `./package.json` (`require.resolve` would need that):
@@ -350,7 +381,7 @@ export function loadProfile(
    }
    initProfile(dir, template)
  }
-  const manifest = readProfileManifest(binName, dir)
+  const manifest = normalizeShippedProfile(name, dir, readProfileManifest(binName, dir))
  // A hand-written profile manifest may omit the dsh section entirely.
  const bundles = manifest.dsh?.profile?.bundles ?? []
  const layers = bundles.map((packageName): ProfileLayer => {
--- a/packages/boot/app-boot/tests/profile.spec.ts
+++ b/packages/boot/app-boot/tests/profile.spec.ts
@@ -161,6 +161,33 @@ describe('loadProfile', () => {
      .toEqual([...PROFILE_TEMPLATES.web ?? []])
  })

+  it('normalizes only the exact installation-owned headless bundle tuple', () => {
+    const anchor = stageInstallation({
+      '@deepseek-ai/dsh-base': { patch: '[]\n' },
+      '@deepseek-ai/dsh-web-app': { patch: '[]\n' },
+      '@deepseek-ai/dsh-headless': { patch: '[]\n' },
+      'custom-bundle': { patch: '[]\n' },
+    })
+    const home = tmp()
+    const stock = resolveProfileDir('headless', home)
+    initProfile(stock, [
+      '@deepseek-ai/dsh-base', '@deepseek-ai/dsh-web-app', '@deepseek-ai/dsh-headless',
+    ])
+    loadProfile('t', 'headless', anchor, home)
+    expect(readProfileManifest('t', stock).dsh?.profile?.bundles)
+      .toEqual(['@deepseek-ai/dsh-base', '@deepseek-ai/dsh-headless'])
+
+    const customHome = tmp()
+    const custom = resolveProfileDir('headless', customHome)
+    initProfile(custom, [
+      '@deepseek-ai/dsh-base', '@deepseek-ai/dsh-web-app', '@deepseek-ai/dsh-headless', 'custom-bundle',
+    ])
+    loadProfile('t', 'headless', anchor, customHome)
+    expect(readProfileManifest('t', custom).dsh?.profile?.bundles).toEqual([
+      '@deepseek-ai/dsh-base', '@deepseek-ai/dsh-web-app', '@deepseek-ai/dsh-headless', 'custom-bundle',
+    ])
+  })
+
  it('fails loud when a listed bundle declares no dsh.bundle', () => {
    const anchor = stageInstallation({ 'not-a-bundle': {} })
    const home = tmp()
--- a/packages/bundle/README.i18n.yaml
+++ b/packages/bundle/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/bundle/README.md
-README.md: af06fe921a66378894a4ab0174ef403499f5f68c
-README.zh.md: b9656649782a638a3b39b4e1e6d330476b0732ba
+README.md: 696aa9ef7bbed23774f2b9ab2648ca83edcf0978
+README.zh.md: 2bb22c7949d759f404288548ea0eccfa0aac866b
--- a/packages/bundle/README.md
+++ b/packages/bundle/README.md
@@ -8,6 +8,6 @@ Profile bundles: npm packages whose manifest declares `"dsh": { "bundle": { "pat
 |---|---|---|
 | [`base/`](base/README.md) | The shared dsh core every profile applies first | — (patch only) |
 | [`web-app/`](web-app/README.md) | Browser surface: web patch layer + runtime glue plugin | mounts rows |
-| [`headless/`](headless/README.md) | One-shot task mode over base + web-app | mounts `headless-runner` |
+| [`headless/`](headless/README.md) | Direct one-shot task mode over base, with no Host or Web layer | mounts `headless-runner` |

 In-box bundles resolve from the dsh installation; out-of-tree bundles install into a profile through `dsh plugin --profile <name> add <package>`.
--- a/packages/bundle/README.zh.md
+++ b/packages/bundle/README.zh.md
@@ -8,6 +8,6 @@ Profile 组合包：在 manifest（元数据清单）中声明 `"dsh": { "bundle
 |---|---|---|
 | [`base/`](base/README.md) | 每个 profile 最先应用的共享 dsh 核心 | —（仅 patch） |
 | [`web-app/`](web-app/README.md) | 浏览器表层：web patch 层 + 运行时粘合插件 | 挂载多条配置行 |
-| [`headless/`](headless/README.md) | 叠加在 base + web-app 之上的一次性任务模式 | 挂载 `headless-runner` |
+| [`headless/`](headless/README.md) | 直接运行在 base 之上的一次性任务模式，不含 Host 或 Web 层 | 挂载 `headless-runner` |

 内置组合包从 dsh 安装目录解析；树外（out-of-tree）组合包通过 `dsh plugin --profile <name> add <package>` 安装进 profile。
--- a/packages/bundle/base/README.i18n.yaml
+++ b/packages/bundle/base/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/bundle/base/README.md
-README.md: 301d397d4c87687b382665cf63af47ab5e3f85be
-README.zh.md: f007bc817b6cbad84725fe8abe72549cf67d8cd7
+README.md: fb003908a262dc21edd3c9d49c972e487534f367
+README.zh.md: 13e64db6d34374fac63bf9bfd60544fc46b86f35
--- a/packages/bundle/base/README.md
+++ b/packages/bundle/base/README.md
@@ -2,7 +2,7 @@

 English | [中文](README.zh.md)

-The shared dsh core as a profile bundle: [`cordis.patch.yml`](cordis.patch.yml) inserts every base plugin row — model adapters, tools, persistence, policy, settings/credentials, repository Plugins, telemetry — over the empty profile root, as the first layer of every profile's `dsh.profile.bundles` list. Later bundle layers (e.g. [`dsh-web-app`](../web-app/README.md)) and the user's profile `cordis.patch.yml` override these rows by id; a patch replaces a row's whole `config`, so mode-specific values live in mode bundles, not here. The package has no runtime API; the profile composer resolves the patch through the `dsh.bundle.patch` manifest field, never through code.
+The shared dsh core as a profile bundle: [`cordis.patch.yml`](cordis.patch.yml) inserts every base plugin row — model adapters, the shared [`agent-default-model`](../../core/agent-default-model/README.md) selection, tools, persistence, policy, settings/credentials, repository Plugins, telemetry — over the empty profile root, as the first layer of every profile's `dsh.profile.bundles` list. Later bundle layers (e.g. [`dsh-web-app`](../web-app/README.md)) and the user's profile `cordis.patch.yml` override these rows by id; a patch replaces a row's whole `config`, so mode-specific values live in mode bundles, not here. The package has no runtime API; the profile composer resolves the patch through the `dsh.bundle.patch` manifest field, never through code.

 The row set and its rationale are documented inline in the patch file; the [generated composition graph](../../../apps/cli/composition.md) renders it.

--- a/packages/bundle/base/README.zh.md
+++ b/packages/bundle/base/README.zh.md
@@ -2,7 +2,7 @@

 [English](README.md) | 中文

-以 profile 组合包形式交付的共享 dsh 核心：[`cordis.patch.yml`](cordis.patch.yml) 在空的 profile 根之上插入全部基础插件行——模型适配器、工具、持久化、策略、settings／credentials、repository 插件、遥测——作为每个 profile 的 `dsh.profile.bundles` 列表中的第一层。后续的组合包层（例如 [`dsh-web-app`](../web-app/README.md)）和用户 profile 的 `cordis.patch.yml` 按 id 覆盖这些行；patch 会替换目标行的整个 `config`，因此模式专属的值放在各模式组合包中，而不是这里。该包没有运行时 API；profile 组合器通过 manifest（元数据清单）的 `dsh.bundle.patch` 字段解析 patch，绝不通过代码。
+以 profile 组合包形式交付的共享 dsh 核心：[`cordis.patch.yml`](cordis.patch.yml) 在空的 profile 根之上插入全部基础插件行——模型适配器、共享的 [`agent-default-model`](../../core/agent-default-model/README.md) 选择、工具、持久化、策略、settings／credentials、repository 插件、遥测——作为每个 profile 的 `dsh.profile.bundles` 列表中的第一层。后续的组合包层（例如 [`dsh-web-app`](../web-app/README.md)）和用户 profile 的 `cordis.patch.yml` 按 id 覆盖这些行；patch 会替换目标行的整个 `config`，因此模式专属的值放在各模式组合包中，而不是这里。该包没有运行时 API；profile 组合器通过 manifest（元数据清单）的 `dsh.bundle.patch` 字段解析 patch，绝不通过代码。

 行集合及其设计依据以行内注释写在 patch 文件里；[生成的组合图](../../../apps/cli/composition.md)负责渲染它。

--- a/packages/bundle/base/cordis.patch.yml
+++ b/packages/bundle/base/cordis.patch.yml
@@ -65,6 +65,14 @@
    - id: agent
      name: '@deepseek-ai/dsh-agent'

+    # The transport-independent default for Agents created by front doors.
+    # Settings may supply a saved selection; consumers read it at creation time.
+    - id: agent-default-model
+      name: '@deepseek-ai/dsh-agent-default-model'
+      config:
+        provider: deepseek-official
+        model: deepseek-v4-flash
+
    - id: tasks
      name: '@deepseek-ai/dsh-tasks-local'

--- a/packages/bundle/base/package.json
+++ b/packages/bundle/base/package.json
@@ -35,6 +35,7 @@
    "@cordisjs/plugin-hmr": "workspace:*",
    "@cordisjs/plugin-timer": "workspace:*",
    "@deepseek-ai/dsh-agent": "workspace:^",
+    "@deepseek-ai/dsh-agent-default-model": "workspace:^",
    "@deepseek-ai/dsh-agent-loop": "workspace:^",
    "@deepseek-ai/dsh-bash-env": "workspace:^",
    "@deepseek-ai/dsh-bash-sandbox": "workspace:^",
--- a/packages/bundle/headless/README.i18n.yaml
+++ b/packages/bundle/headless/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/bundle/headless/README.md
-README.md: 661b377817482d22f58f22b573075722646729a2
-README.zh.md: 8d3ed1c0f99b9245d27c68887aa7b2301368a17b
+README.md: fbdf80be3d587b0ef526c1a36952a761035f7312
+README.zh.md: fa1b5ac280eb9020d71035cc6b09ab2508bff45d
--- a/packages/bundle/headless/README.md
+++ b/packages/bundle/headless/README.md
@@ -2,11 +2,13 @@

 English | [中文](README.zh.md)

-The dsh one-shot bundle. [`cordis.patch.yml`](cordis.patch.yml) rides over [`dsh-base`](../base/README.md) + [`dsh-web-app`](../web-app/README.md): it moves the webserver to an OS-assigned port (parallel runs never collide), silences the URL line, and inserts this package's `headless-runner` plugin (config `{task}`). The runner drives one task turn through the in-process API carrier (`InProcessApiClient` over `toFetchHandler(ctx.apiProxy)`, so the full wire chain — serialization, zod, SSE framing — really runs), waits at idle until that mux has consumed the session's final event sequence, aggregates the turn's final assistant text, writes it to stdout, and requests exit (completed → 0, else 1) through the launcher-provided `ctx.headlessIo` seam. The Web composition stays mounted, so the running session is observable in a browser at the stderr-announced URL. The launcher patches the task text in (`dsh run "task"`), and fails loud when the selected profile lacks this row.
+The dsh one-shot bundle. [`cordis.patch.yml`](cordis.patch.yml) rides directly over [`dsh-base`](../base/README.md): it supplies the coding persona and tool mode, disables HMR, mounts Code Mode's worker as a core execution capability, and inserts this package's `headless-runner` plugin (config `{task}`). It mounts no Host, HTTP server, Web runtime, or browser plugin.
+
+After the Loader settles, the runner reads the shared [`ctx.agentDefaultModel`](../../core/agent-default-model/README.md), creates one fresh persisted Agent through `ctx.agents`, submits the task as an ordinary user message, and waits for quiescence. It flushes the Session before folding the owned durable event interval, writes the last non-empty assistant text to stdout, and requests exit through the launcher-provided `ctx.headlessIo` seam (final `turn/end` completed → 0, otherwise 1). A terminal `error` reason also writes its code and message to stderr; successful runs keep stderr empty. The process opens no listening port. The launcher patches the task text in (`dsh run "task"`) and fails loud when the selected profile lacks this row.

 ## Model Experience

-None, as the runner submits the task as an ordinary user message over the shared composition; prompts and tools belong to the base/web bundles.
+None, as the runner submits the task as an ordinary user message; prompts and tools belong to the base and headless bundle rows.

 #### KV Cache effect

@@ -14,5 +16,5 @@ None; the runner adds nothing to the request prefix.

 ## Known Limitations and Deferred Work

- **One turn only** — the runner anchors on the first message-triggered turn and exits at its end; queued follow-ups and multi-turn tasks are out of scope.
+- **One submitted task only** — the runner has no interactive follow-up surface; it waits through any work the Agent completes before returning to idle and prints the last non-empty assistant message in that interval.
 - **`ctx.headlessIo` is launcher-owned** — booting the headless profile outside the `dsh` launcher fails loud at activation until the host provides the seam.
--- a/packages/bundle/headless/README.zh.md
+++ b/packages/bundle/headless/README.zh.md
@@ -2,11 +2,13 @@

 [English](README.md) | 中文

-dsh 一次性任务组合包。[`cordis.patch.yml`](cordis.patch.yml) 叠加在 [`dsh-base`](../base/README.md) + [`dsh-web-app`](../web-app/README.md) 之上：把 webserver 移到 OS 分配的端口（并行运行绝不冲突），关闭 URL 行输出，并插入本包的 `headless-runner` 插件（配置为 `{task}`）。runner 通过进程内 API 载体（架在 `toFetchHandler(ctx.apiProxy)` 之上的 `InProcessApiClient`，因此序列化、zod、SSE（Server-Sent Events）帧封装这整条 wire 链路都会真实运行）驱动一个任务轮次，在 idle 时等待该 mux 消费完会话的最终事件序号，再聚合该轮次最终的 assistant 文本，写到 stdout，并经启动器提供的 `ctx.headlessIo` seam 请求退出（完成 → 0，否则 1）。Web 组合保持挂载，因此运行中的会话可在浏览器中通过 stderr 公告的 URL 观察。启动器把任务文本 patch 进来（`dsh run "task"`）；若所选 profile 缺少该行，则显式报错。
+dsh 一次性任务组合包。[`cordis.patch.yml`](cordis.patch.yml) 直接叠加在 [`dsh-base`](../base/README.md) 之上：提供编码 persona 和工具模式、禁用 HMR（热模块替换）、将 Code Mode 的 worker 作为核心执行能力挂载，并插入本包的 `headless-runner` 插件（配置为 `{task}`）。它不挂载任何 Host、HTTP server、Web runtime 或浏览器插件。
+
+Loader 结算后，runner 读取共享的 [`ctx.agentDefaultModel`](../../core/agent-default-model/README.md)，通过 `ctx.agents` 创建一个全新的持久化 Agent（智能体），将任务作为普通用户消息提交，并等待完全停稳。它对 Session 执行 flush 后再汇总自身持有的持久化事件区间，将最后一条非空 assistant 文本写入 stdout，再经启动器提供的 `ctx.headlessIo` seam 请求退出（最终 `turn/end` 完成 → 0，否则为 1）。最终 reason 为 `error` 时，还会将持久化的 code 与 message 写入 stderr；成功运行时 stderr 保持为空。进程不会打开监听端口。启动器把任务文本 patch 进来（`dsh run "task"`）；若所选 profile 缺少该行，则显式报错。

 ## 模型体验

-无。runner 把任务作为普通用户消息经共享组合提交；提示词与工具归 base／web 组合包所有。
+无影响，因为 runner 把任务作为普通用户消息提交；提示词与工具归 base 和 headless 组合包中的相应行所有。

 #### KV Cache 影响

@@ -14,5 +16,5 @@ dsh 一次性任务组合包。[`cordis.patch.yml`](cordis.patch.yml) 叠加在

 ## 已知限制与延期工作

- **只运行一个轮次**：runner 锚定第一个由消息触发的轮次，并在其结束时退出；排队的后续消息与多轮任务不在范围内。
+- **只提交一个任务**：runner 没有用于交互式后续输入的 surface；它会等待 Agent 在返回 idle 前完成的所有工作，并打印该区间内最后一条非空 assistant 消息。
 - **`ctx.headlessIo` 由启动器持有**：在 `dsh` 启动器之外启动 headless profile 会在激活时明确报错，直到宿主提供该 seam。
--- a/packages/bundle/headless/cordis.patch.yml
+++ b/packages/bundle/headless/cordis.patch.yml
@@ -1,21 +1,26 @@
-# The dsh-headless bundle patch: one-shot task mode over dsh-base +
-# dsh-web-app. The web composition stays mounted (the session is observable
-# in a browser while it runs); this layer silences the URL line and the
-# GUI-orientation surface context (this user is not in the GUI), moves the
-# webserver to an OS-assigned port so parallel headless runs never collide,
-# and mounts the one-shot runner. The launcher patches the runner's `task`.
+# The dsh-headless bundle patch: one-shot task mode directly over dsh-base.
+# It mounts no Host, HTTP server, Web runtime, or browser plugin. The launcher
+# patches the runner's `task`; the direct driver creates an Agent through the
+# core registry and prints the final durable assistant message.

- id: webserver
+- id: system-prompt
  config:
-    host: 127.0.0.1
-    port: 0
+    persona: >-
+      You are a coding agent powered by the {{model}} model. Your working directory is {{cwd}}.

- id: web-runtime
+# One-shot runs never watch or reload their composition.
+- id: hmr
+  disabled: true
+
+- id: tools
  config:
-    mode: production
-    printUrl: false
-    surfaceContext: false
+    # Keep the same temporary process-wide Code Mode opt-in as the Web surface.
+    mode: !!js process.env.DSH_TOOLS_MODE

 - insert:
+    # Code Mode is a core execution capability, not a Web component.
+    - id: code-runtime
+      name: '@deepseek-ai/dsh-code-runtime-worker'
+
    - id: headless-runner
      name: '@deepseek-ai/dsh-headless'
--- a/packages/bundle/headless/package.json
+++ b/packages/bundle/headless/package.json
@@ -1,6 +1,6 @@
 {
  "name": "@deepseek-ai/dsh-headless",
-  "description": "The dsh one-shot bundle: a patch layer over dsh-base + dsh-web-app plus the runner plugin driving one task turn through the in-process API carrier",
+  "description": "The dsh one-shot bundle: a direct core Agent/Session runner over dsh-base with no Host, HTTP, or browser layer",
  "version": "0.0.1",
  "private": true,
  "type": "module",
@@ -32,22 +32,23 @@
    }
  },
  "dependencies": {
+    "@deepseek-ai/dsh-code-runtime-worker": "workspace:^",
    "schemastery": "^3.18.0"
  },
  "peerDependencies": {
    "@deepseek-ai/dsh-agent": "^0.0.1",
-    "@deepseek-ai/dsh-host-apiproxy": "^0.0.1",
-    "@deepseek-ai/dsh-host-webserver": "^0.0.1",
+    "@deepseek-ai/dsh-agent-default-model": "^0.0.1",
    "@deepseek-ai/dsh-invariants": "^0.0.1",
+    "@deepseek-ai/dsh-llm": "^0.0.1",
    "@deepseek-ai/dsh-session": "^0.0.1",
    "cordis": "^4.0.0-rc.7"
  },
  "devDependencies": {
    "@cordisjs/plugin-loader": "workspace:^",
    "@deepseek-ai/dsh-agent": "workspace:^",
-    "@deepseek-ai/dsh-host-apiproxy": "workspace:^",
-    "@deepseek-ai/dsh-host-webserver": "workspace:^",
+    "@deepseek-ai/dsh-agent-default-model": "workspace:^",
    "@deepseek-ai/dsh-invariants": "workspace:^",
+    "@deepseek-ai/dsh-llm": "workspace:^",
    "@deepseek-ai/dsh-session": "workspace:^",
    "cordis": "^4.0.0-rc.7"
  }
--- a/packages/bundle/headless/src/index.ts
+++ b/packages/bundle/headless/src/index.ts
@@ -1,36 +1,33 @@
 /**
- * @deepseek-ai/dsh-headless — the one-shot headless bundle: the bundle patch
- * (`cordis.patch.yml`) rides over dsh-base + dsh-web-app (the headless
- * session is web-observable while it runs — same composition), and this
- * runner plugin drives one task through the in-process API carrier
- * (InProcessApiClient over toFetchHandler(ctx.apiProxy), so the full wire
- * chain — serialization, zod, SSE framing — really runs), prints the final
- * assistant text at agent quiescence, and exits (completed → 0, else 1). The
- * task text arrives as launcher-patched config (`dsh run "task"`).
+ * @deepseek-ai/dsh-headless — one-shot direct Agent driver. The bundle patch
+ * rides over dsh-base without Host, HTTP, or browser plugins; this runner
+ * creates one Agent through the core registry, drives the task to quiescence,
+ * flushes its Session, prints the final assistant text, and exits.
+ *
 * @module @deepseek-ai/dsh-headless
 */

+import { randomUUID } from 'node:crypto'
 import type { Context } from 'cordis'
 import z from 'schemastery'
-import { InProcessApiClient, toFetchHandler } from '@deepseek-ai/dsh-host-apiproxy'
-// Empty type imports carry the httpServer and agent/status Context merges used below.
-import type {} from '@deepseek-ai/dsh-host-webserver'
-import type {} from '@deepseek-ai/dsh-agent'
+import { installModelSelection } from '@deepseek-ai/dsh-agent'
+import type { ModelSelectionRef } from '@deepseek-ai/dsh-agent'
+import type {} from '@deepseek-ai/dsh-agent-default-model'
+import { createUserMessage } from '@deepseek-ai/dsh-llm'
+import { SessionId } from '@deepseek-ai/dsh-session'
+import type { SessionEvent } from '@deepseek-ai/dsh-session'
 // Empty type import carries the loader Context merge for the settlement await.
 import type {} from '@cordisjs/plugin-loader'
-import type { MuxFrame } from '@deepseek-ai/dsh-host-apiproxy/api'
-import type { RpcRequest, RpcResponse } from '@deepseek-ai/dsh-host-apiproxy/api/rpc'
-import type { SessionId } from '@deepseek-ai/dsh-session'

 /** Stable Cordis plugin name. */
 export const name = 'headless-runner'

-/** Services required before the one-shot turn can start. */
-export const inject = ['apiProxy', 'httpServer']
+/** Core services required before the one-shot turn can start. */
+export const inject = ['agentDefaultModel', 'agents', 'sessions']

 /** Plugin config: the task, patched in by the launcher. */
 export interface Config {
-  /** The prompt text for the single turn. */
+  /** The prompt text for the single run. */
  task: string
 }

@@ -38,16 +35,15 @@ export const Config: z<Config> = z.object({
  task: z.string().required(),
 })

-/** Outcome of one headless run: aggregated final text plus the last turn-end reason kind. */
-interface TurnOutcome {
+/** Outcome of one owned run interval. */
+interface RunOutcome {
  text: string
-  reason: string
+  reason: SessionEvent<'turn/end'>['data']['reason'] | undefined
 }

 /**
- * The process-facing effects of one run, injectable for tests: output
- * streams and the exit request (the launcher wires it to its bounded
- * shutdown controller).
+ * Process-facing effects of one run, injectable for tests. The launcher owns
+ * bounded tree shutdown and wires `exit()` to it.
 */
 export interface HeadlessIo {
  stdout: { write(chunk: string): unknown }
@@ -56,127 +52,94 @@ export interface HeadlessIo {
  exit(code: number): void
 }

-/** Host seam: the launcher provides the exit wiring before the tree mounts. */
 declare module 'cordis' {
  interface Context {
-    /** Process-facing effects for the one-shot headless runner. */
+    /** Process-facing effects provided before the headless tree mounts. */
    headlessIo?: HeadlessIo
  }
 }

-/** Unwrap an RpcResponse or fail loud: business errors print and exit 1. */
-async function unwrap<T>(response: RpcResponse<T>, io: HeadlessIo): Promise<T> {
-  if (response.result.ok) return response.result.value
-  const { code, message } = response.result.error
-  io.stderr.write(`dsh: ${code}: ${message}\n`)
-  io.exit(1)
-  // Exit is asynchronous (bounded tree disposal); park this turn forever so
-  // no further request rides a session that is already being torn down.
-  return new Promise<never>(() => {})
-}
-
-/**
- * Consume mux frames until the agent reaches idle, per the one-shot CLI
- * idle-to-idle contract: the stream opens immediately before the prompt, and
- * its first observed turn/start begins the task. Text is the last committed
- * assistant message of the whole interval (steering or injected work may run
- * further turns before quiescence), and the outcome reason is the final
- * turn/end's kind. Idleness is signalled out of band by the caller's
- * `agent/status` subscription; the stream itself carries no status frame.
- * @param frames - the mux stream opened before the prompt.
- * @param sessionId - the headless session.
- * @param idle - resolves to the final session-event sequence when the agent reaches quiescence.
- * @param io - process-facing effects for stream diagnostics.
- * @returns the aggregated outcome.
- */
-async function consumeUntilIdle(
-  frames: AsyncIterable<RpcRequest<MuxFrame>>,
-  sessionId: SessionId,
-  idle: Promise<number>,
-  io: HeadlessIo,
-): Promise<TurnOutcome> {
+/** Aggregate the last assistant text and turn outcome in one owned interval. */
+function summarize(events: readonly SessionEvent[], firstSeq: number): RunOutcome {
  let started = false
  let text = ''
-  let reason: string = 'error'
-  let observedSeq = -1
-  let resolveProgress: (() => void) | undefined
-  const streamDone = (async () => {
-    try {
-      for await (const frame of frames) {
-        const payload = frame.payload
-        if (payload.type === 'stream/error') return
-        if (payload.type !== 'session/event' || payload.sessionId !== sessionId) continue
-        const event = payload.event
-        observedSeq = event.seq
-        resolveProgress?.()
-        resolveProgress = undefined
-        if (event.type === 'turn/start') {
-          started = true
-          continue
-        }
-        if (!started) continue
-        if (event.type === 'assistant/message') {
-          const joined = event.data.message.content.filter(block => block.type === 'text').map(block => block.text).join('')
-          if (joined !== '') text = joined
-        }
-        if (event.type === 'turn/end') reason = event.data.reason.kind
-      }
-    } catch (error: unknown) {
-      io.stderr.write(`dsh: event stream failed: ${String(error)}\n`)
+  let reason: SessionEvent<'turn/end'>['data']['reason'] | undefined
+  for (const event of events) {
+    if (event.seq < firstSeq) continue
+    if (event.type === 'turn/start') {
+      started = true
+      continue
    }
-  })()
-  const streamEnded = streamDone.then(() => 'ended' as const)
-  const idleSeq = await idle
-  while (observedSeq < idleSeq) {
-    const progress = new Promise<'progress'>((resolve) => { resolveProgress = () => { resolve('progress') } })
-    if (await Promise.race([progress, streamEnded]) === 'ended') break
+    if (!started) continue
+    if (event.type === 'assistant/message') {
+      const joined = event.data.message.content
+        .filter(block => block.type === 'text')
+        .map(block => block.text)
+        .join('')
+      if (joined !== '') text = joined
+    }
+    if (event.type === 'turn/end') reason = event.data.reason
  }
  return { text, reason }
 }

+/** Report an unexpected direct-driver failure and request a failing exit. */
+function fail(io: HeadlessIo, error: unknown): void {
+  io.stderr.write(`dsh: ${error instanceof Error ? error.message : String(error)}\n`)
+  io.exit(1)
+}
+
 /**
- * Run one headless task to quiescence and request exit (completed → 0, else 1).
- * @param ctx - plugin context carrying apiProxy, httpServer, and the launcher's headlessIo.
- * @param config - validated {@link Config}.
+ * Run one task through a freshly created Agent and request process exit.
+ * @param ctx - plugin context carrying the Agent, default model, Session, and launcher IO services.
+ * @param task - one-shot task text.
+ * @param io - process-facing effects.
+ */
+async function run(ctx: Context, task: string, io: HeadlessIo): Promise<void> {
+  // Loader siblings mount concurrently. Await the complete application before
+  // creating an Agent so its scoped tools and adapters are not half-composed.
+  await ctx.get('loader')?.await()
+  const agents = ctx.get('agents')
+  const defaultModel = ctx.get('agentDefaultModel')
+  const sessions = ctx.get('sessions')
+  // Early process shutdown can dispose the tree while settlement is pending.
+  if (agents === undefined || defaultModel === undefined || sessions === undefined) return
+
+  const selection = defaultModel.currentSelection()
+  const { agent } = await agents.create({
+    sessionId: SessionId(`session-${randomUUID()}`),
+    meta: { cwd: process.cwd() },
+    agentOptions: { provider: selection.provider, model: selection.model },
+    setup: (agentCtx) => {
+      const selected: ModelSelectionRef = { current: selection, assembled: undefined }
+      installModelSelection(agentCtx, selected)
+    },
+  })
+  await agent.whenIdle()
+  const firstSeq = agent.session.seq
+  agent.followup(createUserMessage({
+    content: [{ type: 'text', text: task }],
+    source: { kind: 'user' },
+  }))
+  await agent.whenIdle()
+  await sessions.flush(agent.session)
+  const outcome = summarize(agent.session.events, firstSeq)
+  io.stdout.write(outcome.text + '\n')
+  if (outcome.reason?.kind === 'error') {
+    io.stderr.write(`dsh: ${outcome.reason.error.code}: ${outcome.reason.error.message}\n`)
+  }
+  io.exit(outcome.reason?.kind === 'completed' ? 0 : 1)
+}
+
+/**
+ * Mount the one-shot direct driver.
+ * @param ctx - plugin context carrying core services and the launcher-owned IO seam.
+ * @param config - validated task config.
 */
 export function apply(ctx: Context, config: Config): void {
  const io = ctx.headlessIo
  if (io === undefined) {
    throw new Error('headless-runner: the launcher must provide ctx.headlessIo before the tree mounts')
  }
-  // Fire-and-forget by design: the run outlives plugin activation, and every
-  // failure path inside ends in io.exit, not a rejection.
-  void (async () => {
-    // The Loader mounts sibling rows concurrently and this plugin's inject
-    // gate covers only apiProxy/httpServer; prompting before the agent loop,
-    // adapters, and tools settle would fail the turn on a half-mounted tree.
-    // The old launcher ran strictly after settled boot — preserve that.
-    // A tree disposed mid-settlement (early SIGTERM) has nothing to run.
-    await ctx.get('loader')?.await()
-    if (ctx.get('httpServer') === undefined) return
-    // The headless session is web-observable while it runs (same composition).
-    io.stderr.write(`dsh: observing at http://127.0.0.1:${String(ctx.httpServer.port)}\n`)
-    const api = new InProcessApiClient(toFetchHandler(ctx.apiProxy))
-    const created = await unwrap(await api.sessions.create({}), io)
-    // Open the stream before prompting so no frame is lost. The quiescence
-    // anchor below is an in-process ctx subscription, so a remote-carrier
-    // port of this runner must replace it with a wire-visible idle signal.
-    const abort = new AbortController()
-    const frames = api.events.mux({}, abort.signal)
-    const idle = new Promise<number>((resolve) => {
-      ctx.on('agent/status', ({ agent, status }) => {
-        if (agent.id === created.sessionId && status === 'idle') resolve(agent.session.seq - 1)
-      })
-    })
-    const done = consumeUntilIdle(frames, created.sessionId, idle, io)
-    await unwrap(await api.sessions.prompt({
-      sessionId: created.sessionId,
-      mode: 'queue',
-      content: [{ type: 'text', text: config.task }],
-    }), io)
-    const outcome = await done
-    io.stdout.write(outcome.text + '\n')
-    abort.abort()
-    io.exit(outcome.reason === 'completed' ? 0 : 1)
-  })()
+  void run(ctx, config.task, io).catch((error: unknown) => { fail(io, error) })
 }
--- a/packages/bundle/headless/tests/headless.spec.ts
+++ b/packages/bundle/headless/tests/headless.spec.ts
@@ -1,170 +1,184 @@
-/**
- * One-shot runner behavior over a scripted in-process API: idle-to-idle
- * aggregation (last text of the whole interval), exit-code mapping by the
- * final turn-end reason, stream-error and RPC-error paths, and the
- * launcher-owned `ctx.headlessIo` requirement.
- */
+/** Direct one-shot Agent driving, durable aggregation, flushing, and exit mapping. */

 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
-import type { Agent } from '@deepseek-ai/dsh-agent'
+import AgentRegistry, { Inbox } from '@deepseek-ai/dsh-agent'
+import type { Agent, AgentHandle, CreateAgentOptions } from '@deepseek-ai/dsh-agent'
+import AgentDefaultModelService from '@deepseek-ai/dsh-agent-default-model'
+import { createAssistantMessage } from '@deepseek-ai/dsh-llm'
+import SessionStore from '@deepseek-ai/dsh-session'
+import type { Session, UserMessage } from '@deepseek-ai/dsh-session'
 import { apply, Config, type HeadlessIo } from '../src/index.ts'

-interface ScriptedEvent { type: string; seq?: number; time?: number; sessionId?: string; data: Record<string, unknown> }
-
-let nextSeq = 0
-/** Stamp the envelope fields the wire schema requires. */
-function stamped(event: ScriptedEvent): ScriptedEvent {
-  nextSeq += 1
-  return { seq: nextSeq, time: nextSeq, ...event }
+interface Script {
+  before?(session: Session): void
+  afterPrompt(session: Session, message: UserMessage): Promise<void> | void
 }

-interface RpcShapedRequest { rpcId: string }
-
-interface ScriptedApiOptions {
-  promptFails?: boolean
-  framesAfterPrompt?: boolean
-  onPrompt?: () => void
+function appendTurn(
+  session: Session,
+  turn: number,
+  message: UserMessage,
+  text: string | undefined,
+  completed: boolean,
+): void {
+  session.append('turn/start', { turn })
+  session.append('step/start', { turn, step: 1 })
+  session.append('user/message', message, { surfaceOp: 'append' })
+  if (text !== undefined) {
+    session.append('assistant/message', {
+      turn,
+      step: 1,
+      message: createAssistantMessage({
+        content: [{ type: 'text', text }],
+        source: { provider: 'test-provider', model: 'test-model' },
+      }),
+    }, { surfaceOp: 'append' })
+  }
+  session.append('step/end', { turn, step: 1 })
+  session.append('turn/end', {
+    turn,
+    reason: completed
+      ? { kind: 'completed' }
+      : { kind: 'aborted', reason: { kind: 'user' } },
+  })
 }

-/** Build a fake apiProxy (echoing rpcIds like the real gateway) whose mux stream replays `events` for the created session. */
-function scriptedApi(events: ScriptedEvent[], options: ScriptedApiOptions = {}): unknown {
-  let releaseFrames = (): void => {}
-  const framesReady = options.framesAfterPrompt === true
-    ? new Promise<void>((resolve) => { releaseFrames = resolve })
-    : Promise.resolve()
-  const prepared = events.map((event) => {
-    if (event.type === 'stream/error') return { streamError: true } as const
-    const { sessionId = 'S1', ...rest } = event
-    return { streamError: false, sessionId, event: stamped(rest) } as const
+/** Mount the real registries around a small scripted Agent factory. */
+async function bench(script: Script): Promise<{
+  ctx: Context
+  run(): Promise<{ code: number; out: string; err: string; order: string[] }>
+}> {
+  const ctx = new Context()
+  await ctx.plugin(SessionStore)
+  await ctx.plugin(AgentRegistry)
+  await ctx.plugin(AgentDefaultModelService, { provider: 'test-provider', model: 'test-model' })
+  ctx.agents.setFactory({
+    async createAgent(ownerCtx: Context, options: CreateAgentOptions): Promise<AgentHandle> {
+      const session = ctx.sessions.create(options.sessionId, {
+        ...options.meta === undefined ? {} : { meta: options.meta },
+      })
+      let idle = Promise.resolve()
+      const agent = {} as Agent
+      const agentCtx = ownerCtx.extend({ agent })
+      Object.assign(agent, {
+        id: session.id,
+        options: options.agentOptions ?? {},
+        session,
+        inbox: new Inbox(session, { inserted: () => {}, discarded: () => {}, claimed: () => {} }),
+        status: 'idle',
+        ctx: agentCtx,
+        cancel: () => {},
+        runMaintenance: () => Promise.reject(new Error('not used')),
+        send: () => {},
+        followup: (message: UserMessage) => {
+          agent.inbox.append('next-turn', message)
+          idle = Promise.resolve().then(() => script.afterPrompt(session, message))
+        },
+        steer: () => {},
+        inject: () => {},
+        whenIdle: () => idle,
+      } satisfies Partial<Agent>)
+      await options.setup?.(agentCtx)
+      script.before?.(session)
+      ctx.agents.register(agent)
+      return { agent, dispose: () => Promise.resolve() }
+    },
+    resume: () => Promise.reject(new Error('not used')),
  })
  return {
-    sessions: {
-      create: (request: RpcShapedRequest) =>
-        Promise.resolve({ rpcId: request.rpcId, result: { ok: true, value: { sessionId: 'S1' } } }),
-      prompt: (request: RpcShapedRequest) => {
-        releaseFrames()
-        options.onPrompt?.()
-        return Promise.resolve(options.promptFails === true
-          // A code from the closed wire union: the carrier schema rejects invented codes.
-          ? { rpcId: request.rpcId, result: { ok: false, error: { code: 'agent-busy', message: 'agent is busy', details: { reason: 'test' } } } }
-          : { rpcId: request.rpcId, result: { ok: true, value: { accepted: true } } })
-      },
-    },
-    events: {
-      mux: async function* () {
-        await framesReady
-        for (const item of prepared) {
-          if (item.streamError) {
-            yield { rpcId: 'e', payload: { type: 'stream/error', error: { code: 'cancelled', message: 'stream broke', details: {} } } }
-            continue
-          }
-          yield { rpcId: 'e', payload: { type: 'session/event', sessionId: item.sessionId, event: item.event } }
+    ctx,
+    run: async () => {
+      let out = ''
+      let err = ''
+      const order: string[] = []
+      ctx.on('session/flush', () => { order.push('flush') })
+      const exited = new Promise<number>((resolve) => {
+        const io: HeadlessIo = {
+          stdout: { write: (chunk: string) => { out += chunk; return true } },
+          stderr: { write: (chunk: string) => { err += chunk; return true } },
+          exit: (code) => { order.push('exit'); resolve(code) },
        }
-      },
+        ctx.provide('headlessIo', io)
+      })
+      apply(ctx, { task: 'do the thing' })
+      return { code: await exited, out, err, order }
    },
  }
 }

-/**
- * Mount the runner against a scripted API, emit the idle transition after the
- * scripted frames drain, and wait for its exit request.
- */
-async function run(
-  events: ScriptedEvent[],
-  options: { promptFails?: boolean; framesAfterPrompt?: boolean; idleInPrompt?: boolean } = {},
-): Promise<{ code: number; out: string; err: string }> {
-  const ctx = new Context()
-  let out = ''
-  let err = ''
-  const exited = new Promise<number>((resolve) => {
-    const io: HeadlessIo = {
-      stdout: { write: (chunk: string) => { out += chunk; return true } },
-      stderr: { write: (chunk: string) => { err += chunk; return true } },
-      exit: resolve,
-    }
-    ctx.provide('headlessIo', io)
-  })
-  const emitIdle = (): void => {
-    ctx.emit('agent/status', { agent: { id: 'S1', session: { seq: nextSeq + 1 } } as Agent, status: 'idle' })
-  }
-  ctx.provide('apiProxy', scriptedApi(events, {
-    ...options.promptFails === undefined ? {} : { promptFails: options.promptFails },
-    ...options.framesAfterPrompt === undefined ? {} : { framesAfterPrompt: options.framesAfterPrompt },
-    ...options.idleInPrompt === true ? { onPrompt: emitIdle } : {},
-  }) as never)
-  ctx.provide('httpServer', { port: 12345 } as never)
-  apply(ctx, { task: 'do the thing' })
-  // Quiescence is out of band: give the scripted stream a beat to drain, then
-  // flip the agent idle exactly as the loop would. Foreign agents and
-  // non-idle transitions must not settle the run.
-  if (options.idleInPrompt !== true) {
-    await new Promise(resolve => setTimeout(resolve, 10))
-    ctx.emit('agent/status', { agent: { id: 'OTHER' } as Agent, status: 'idle' })
-    ctx.emit('agent/status', { agent: { id: 'S1' } as Agent, status: 'running' })
-    emitIdle()
-  }
-  const code = await exited
-  await ctx.fiber.dispose()
-  return { code, out, err }
-}
-
-const startupTurn: ScriptedEvent = { type: 'turn/start', data: { turn: 0, trigger: { kind: 'startup' } } }
-const messageTurn: ScriptedEvent = { type: 'turn/start', data: { turn: 1, trigger: { kind: 'message' } } }
-const text = (turn: number, value: string): ScriptedEvent => ({
-  type: 'assistant/message',
-  data: { turn, message: { content: [{ type: 'text', text: value }] } },
-})
-const end = (turn: number, reason: string): ScriptedEvent => ({ type: 'turn/end', data: { turn, reason: { kind: reason } } })
-
 describe('headless runner', () => {
-  it('aggregates to quiescence: last text wins across turns, final turn-end reason maps to exit 0', async () => {
-    const { code, out, err } = await run([
-      // Frames before the first turn/start are outside the task interval.
-      { type: 'assistant/message', data: { turn: 0, message: { content: [{ type: 'text', text: 'pre-task noise' }] } } },
-      startupTurn,
-      // Off-session, non-text, and text-empty frames never affect the aggregate.
-      { type: 'assistant/message', sessionId: 'OTHER', data: { turn: 1, message: { content: [{ type: 'text', text: 'other session' }] } } },
-      { type: 'assistant/message', data: { turn: 1, message: { content: [{ type: 'tool_call', text: 'ignored' }] } } },
-      text(0, 'draft'),
-      end(0, 'completed'),
-      messageTurn,
-      text(1, 'final answer'),
-      end(1, 'completed'),
-    ])
-    expect(code).toBe(0)
-    expect(out).toBe('final answer\n')
-    expect(err).toContain('observing at http://127.0.0.1:12345')
+  it('aggregates the final text across the complete idle-to-idle interval and flushes before exit', async () => {
+    const test = await bench({
+      before(session) {
+        const setupMessage = {
+          role: 'user', content: [{ type: 'text', text: 'setup' }], source: { kind: 'user' }, id: 'setup',
+        } as UserMessage
+        appendTurn(session, 0, setupMessage, 'pre-task noise', true)
+      },
+      async afterPrompt(session, message) {
+        await Promise.resolve()
+        appendTurn(session, 1, message, '', true)
+        appendTurn(session, 2, message, 'final answer', true)
+      },
+    })
+    const result = await test.run()
+    expect(result).toEqual({
+      code: 0,
+      out: 'final answer\n',
+      err: '',
+      order: ['flush', 'exit'],
+    })
+    await test.ctx.fiber.dispose()
  })

-  it('consumes through the idle sequence when queued frames arrive after the status transition', async () => {
-    const { code, out } = await run(
-      [messageTurn, text(1, 'race-free answer'), end(1, 'completed')],
-      { framesAfterPrompt: true, idleInPrompt: true },
-    )
-    expect(code).toBe(0)
-    expect(out).toBe('race-free answer\n')
+  it('waits for asynchronously appended events instead of racing Agent idleness', async () => {
+    const test = await bench({
+      afterPrompt: async (session, message) => {
+        await new Promise(resolve => setTimeout(resolve, 5))
+        appendTurn(session, 1, message, 'race-free answer', true)
+      },
+    })
+    expect(await test.run()).toMatchObject({ code: 0, out: 'race-free answer\n', err: '' })
+    await test.ctx.fiber.dispose()
  })

-  it('exits 1 when the final turn ends for any other reason', async () => {
-    const { code } = await run([messageTurn, end(1, 'aborted')])
-    expect(code).toBe(1)
+  it('exits 1 when the final turn does not complete', async () => {
+    const test = await bench({
+      afterPrompt(session, message) { appendTurn(session, 1, message, undefined, false) },
+    })
+    expect(await test.run()).toMatchObject({ code: 1, out: '\n', err: '' })
+    await test.ctx.fiber.dispose()
  })

-  it('exits 1 when no turn ever starts (idle without work)', async () => {
-    const { code, out } = await run([])
-    expect(code).toBe(1)
-    expect(out).toBe('\n')
+  it('prints the durable model failure when the final turn ends in error', async () => {
+    const test = await bench({
+      afterPrompt(session, message) {
+        session.append('turn/start', { turn: 1 })
+        session.append('step/start', { turn: 1, step: 1 })
+        session.append('user/message', message, { surfaceOp: 'append' })
+        session.append('step/end', { turn: 1, step: 1 })
+        session.append('turn/end', {
+          turn: 1,
+          reason: { kind: 'error', error: { code: 'SERVER', message: 'provider unavailable' } },
+        })
+      },
+    })
+    expect(await test.run()).toMatchObject({
+      code: 1,
+      out: '\n',
+      err: 'dsh: SERVER: provider unavailable\n',
+    })
+    await test.ctx.fiber.dispose()
  })

-  it('keeps the error outcome after a stream error ends the frame consumer early', async () => {
-    const { code } = await run([messageTurn, { type: 'stream/error', data: {} }, end(1, 'completed')])
-    // The consumer stopped at the stream error; the completed turn-end after
-    // it is never observed, so the reason stays 'error'.
-    expect(code).toBe(1)
+  it('exits 1 when the owned interval contains no turn', async () => {
+    const test = await bench({ afterPrompt: () => {} })
+    expect(await test.run()).toMatchObject({ code: 1, out: '\n', err: '' })
+    await test.ctx.fiber.dispose()
  })

-  it('prints an RPC business error and exits 1 without waiting for idle', async () => {
+  it('reports a direct Agent creation failure', async () => {
    const ctx = new Context()
    let err = ''
    const exited = new Promise<number>((resolve) => {
@@ -174,15 +188,16 @@ describe('headless runner', () => {
        exit: resolve,
      } satisfies HeadlessIo)
    })
-    ctx.provide('apiProxy', scriptedApi([messageTurn, end(1, 'completed')], { promptFails: true }) as never)
-    ctx.provide('httpServer', { port: 1 } as never)
+    ctx.provide('agentDefaultModel', { currentSelection: () => ({ provider: 'p', model: 'm' }) } as never)
+    ctx.provide('sessions', { flush: () => Promise.resolve(true) } as never)
+    ctx.provide('agents', { create: () => Promise.reject(new Error('factory exploded')) } as never)
    apply(ctx, { task: 't' })
    expect(await exited).toBe(1)
-    expect(err).toContain('agent-busy')
+    expect(err).toBe('dsh: factory exploded\n')
    await ctx.fiber.dispose()
  })

-  it('reports the stream-failed diagnostic when the event channel dies, still settling at idle', async () => {
+  it('stringifies a non-Error Agent creation failure', async () => {
    const ctx = new Context()
    let err = ''
    const exited = new Promise<number>((resolve) => {
@@ -192,67 +207,52 @@ describe('headless runner', () => {
        exit: resolve,
      } satisfies HeadlessIo)
    })
-    ctx.provide('apiProxy', {
-      sessions: {
-        create: (request: RpcShapedRequest) =>
-          Promise.resolve({ rpcId: request.rpcId, result: { ok: true, value: { sessionId: 'S1' } } }),
-        prompt: (request: RpcShapedRequest) =>
-          Promise.resolve({ rpcId: request.rpcId, result: { ok: true, value: { accepted: true } } }),
+    ctx.provide('agentDefaultModel', { currentSelection: () => ({ provider: 'p', model: 'm' }) } as never)
+    ctx.provide('sessions', { flush: () => Promise.resolve(true) } as never)
+    const rejected = {
+      then(_resolve: (value: never) => void, reject: (reason: unknown) => void): void {
+        reject('factory exploded')
      },
-      events: {
-        // Synchronous throw: the SSE response never forms, so the client-side
-        // iterable rejects — the runner's own catch path, not a carrier frame.
-        mux: () => { throw new Error('channel exploded') },
-      },
-    } as never)
-    ctx.provide('httpServer', { port: 1 } as never)
+    }
+    ctx.provide('agents', { create: () => rejected } as never)
    apply(ctx, { task: 't' })
-    await new Promise(resolve => setTimeout(resolve, 10))
-    ctx.emit('agent/status', { agent: { id: 'S1', session: { seq: nextSeq + 1 } } as Agent, status: 'idle' })
    expect(await exited).toBe(1)
-    expect(err).toContain('event stream failed')
+    expect(err).toBe('dsh: factory exploded\n')
    await ctx.fiber.dispose()
  })

-  it('waits for Loader settlement and abandons the run when the tree died during it', async () => {
+  it('abandons a run when the tree is disposed during Loader settlement', async () => {
    const ctx = new Context()
-    let err = ''
    let exited = false
    ctx.provide('headlessIo', {
      stdout: { write: () => true },
-      stderr: { write: (chunk: string) => { err += chunk; return true } },
+      stderr: { write: () => true },
      exit: () => { exited = true },
    } satisfies HeadlessIo)
-    ctx.provide('apiProxy', scriptedApi([]) as never)
-    // The webserver is provided by a child fiber whose disposal (early
-    // SIGTERM during the boot window) removes the service; settlement
-    // resolves only afterwards, and the runner must abandon rather than
-    // crash on the torn-down port read.
-    const webserverFiber = ctx.plugin((childCtx: Context) => {
-      childCtx.provide('httpServer', { port: 1 } as never)
+    const services = ctx.plugin((child: Context) => {
+      child.provide('agentDefaultModel', { currentSelection: () => ({ provider: 'p', model: 'm' }) } as never)
+      child.provide('sessions', {} as never)
+      child.provide('agents', {} as never)
    })
-    await webserverFiber
+    await services
    let release: () => void
    const settlement = new Promise<void>((resolve) => { release = resolve })
    ctx.provide('loader', { await: () => settlement } as never)
    apply(ctx, { task: 't' })
-    await webserverFiber.dispose()
+    await services.dispose()
    release!()
    await new Promise(resolve => setTimeout(resolve, 10))
-    expect(err).toBe('')
    expect(exited).toBe(false)
    await ctx.fiber.dispose()
  })

  it('fails loud without the launcher-owned headlessIo seam', () => {
    const ctx = new Context()
-    ctx.provide('apiProxy', scriptedApi([]) as never)
-    ctx.provide('httpServer', { port: 1 } as never)
    expect(() => { apply(ctx, { task: 't' }) }).toThrow('must provide ctx.headlessIo')
  })

  it('validates config: the task is required', () => {
-    expect(() => new Config({ } as never)).toThrow()
+    expect(() => new Config({} as never)).toThrow()
    expect(new Config({ task: 'x' })).toEqual({ task: 'x' })
  })
 })
--- a/packages/bundle/headless/tsconfig.json
+++ b/packages/bundle/headless/tsconfig.json
@@ -17,15 +17,15 @@
    {
      "path": "../../../vendor/schemastery"
    },
-    {
-      "path": "../../host/apiproxy"
-    },
-    {
-      "path": "../../host/webserver"
-    },
    {
      "path": "../../core/agent"
    },
+    {
+      "path": "../../core/agent-default-model"
+    },
+    {
+      "path": "../../llm/llm"
+    },
    {
      "path": "../../core/session"
    },
--- a/packages/bundle/web-app/README.i18n.yaml
+++ b/packages/bundle/web-app/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/bundle/web-app/README.md
-README.md: dc35cb4b596b265b70cea81aa5d6784fc1eff65b
-README.zh.md: c9fc86522da9c6b2ea79d1d079c71e5b26007f0a
+README.md: d89ae4a7e28506166498caf0032f864bbb109cc5
+README.zh.md: 746ec2e8b6748a0d72f697d0aea5f3809e7106ee
--- a/packages/bundle/web-app/README.md
+++ b/packages/bundle/web-app/README.md
@@ -2,7 +2,7 @@

 English | [中文](README.zh.md)

-The dsh browser-surface bundle. [`cordis.patch.yml`](cordis.patch.yml) rides over [`dsh-base`](../base/README.md): it sets the coding persona, inserts the Web host rows (webserver, API gateway, workspace, projection cache, storage) and the browser plugin roster, and mounts this package's own `web-runtime` glue plugin (config `{mode, printUrl, surfaceContext, lanAddresses}`). That plugin owns what used to be launcher code: it resolves the built frontend dist through `@deepseek-ai/dsh-frontend`'s exports (workspace knowledge of this bundle, never user config), mounts the [`frontend-static`](../../host/frontend-static/README.md) fallback owner over it, registers the web-surface prompt section and the bash-visible `DSH_WEB_URL`/`DSH_WEB_MODE` runtime variables when `surfaceContext` is true, and prints the `dsh web:` URL line when `printUrl` is true. The `dsh web` launcher alias patches `mode`/`lanAddresses` and the flag family over these rows; [`dsh-headless`](../headless/README.md) layers on top, silences the URL line, and disables the surface context.
+The dsh browser-surface bundle. [`cordis.patch.yml`](cordis.patch.yml) rides over [`dsh-base`](../base/README.md): it sets the coding persona, inserts the Web host rows (webserver, API gateway, workspace, projection cache, storage) and the browser plugin roster, and mounts this package's `web-runtime` glue plugin (config `{mode, printUrl, surfaceContext, lanAddresses}`). That plugin resolves the built frontend dist through `@deepseek-ai/dsh-frontend`'s exports, mounts the [`frontend-static`](../../host/frontend-static/README.md) fallback owner over it, registers the web-surface prompt section and the bash-visible `DSH_WEB_URL`/`DSH_WEB_MODE` runtime variables when `surfaceContext` is true, and prints the `dsh web:` URL line when `printUrl` is true. The `dsh web` launcher alias patches `mode`/`lanAddresses` and the flag family over these rows. [`dsh-headless`](../headless/README.md) is a sibling surface over the same base and does not mount this bundle.

 ## Model Experience

--- a/packages/bundle/web-app/README.zh.md
+++ b/packages/bundle/web-app/README.zh.md
@@ -2,7 +2,7 @@

 [English](README.md) | 中文

-dsh 浏览器表层组合包。[`cordis.patch.yml`](cordis.patch.yml) 叠加在 [`dsh-base`](../base/README.md) 之上：设置 coding persona，插入 Web 宿主行（webserver、API 网关、workspace、投影缓存、存储）与浏览器插件名录，并挂载本包自己的 `web-runtime` 粘合插件（配置为 `{mode, printUrl, surfaceContext, lanAddresses}`）。该插件接管了原先属于启动器的代码：它通过 `@deepseek-ai/dsh-frontend` 的 exports 解析已构建的前端 dist（这是本组合包的 workspace 知识，绝不是用户配置），在其上挂载 [`frontend-static`](../../host/frontend-static/README.md) 回退席位所有者，在 `surfaceContext` 为 true 时注册 web 表层提示词段落和 bash 可见的 `DSH_WEB_URL`／`DSH_WEB_MODE` 运行时变量，并在 `printUrl` 为 true 时打印 `dsh web:` URL 行。`dsh web` 启动器别名把 `mode`／`lanAddresses` 与相应 flag 家族 patch 到这些行上；[`dsh-headless`](../headless/README.md) 再叠加一层，关闭 URL 行并禁用表层上下文。
+dsh 浏览器表层组合包。[`cordis.patch.yml`](cordis.patch.yml) 叠加在 [`dsh-base`](../base/README.md) 之上：设置 coding persona，插入 Web 宿主行（webserver、API 网关、workspace、投影缓存、存储）与浏览器插件名录，并挂载本包的 `web-runtime` 粘合插件（配置为 `{mode, printUrl, surfaceContext, lanAddresses}`）。该插件通过 `@deepseek-ai/dsh-frontend` 的 exports 解析已构建的前端 dist，挂载 [`frontend-static`](../../host/frontend-static/README.md) 回退席位所有者，在 `surfaceContext` 为 true 时注册 web 表层提示词段落和 bash 可见的 `DSH_WEB_URL`／`DSH_WEB_MODE` 运行时变量，并在 `printUrl` 为 true 时打印 `dsh web:` URL 行。`dsh web` 启动器别名把 `mode`／`lanAddresses` 与相应 flag 家族 patch 到这些行上。[`dsh-headless`](../headless/README.md) 是同一 base 之上的同级表层，不挂载本组合包。

 ## 模型体验

--- a/packages/bundle/web-app/cordis.patch.yml
+++ b/packages/bundle/web-app/cordis.patch.yml
@@ -72,13 +72,9 @@
      name: '@deepseek-ai/dsh-host-directory-picker-auto'

    # The API gateway: the transport-agnostic dispatch face every client shape
-    # shares. provider/model are the host default routing — the profile json's
-    # mapping target (user config overrides these engineering defaults).
+    # shares. The base layer's agent-default-model service owns the default model.
    - id: api-gateway
      name: '@deepseek-ai/dsh-host-apiproxy'
-      config:
-        provider: deepseek-official
-        model: deepseek-v4-flash

    # ── layer 2: transport/service ──────────────────────────────────────────────

--- a/packages/client/connection/src/client/api.ts
+++ b/packages/client/connection/src/client/api.ts
@@ -12,7 +12,7 @@ export type {
  WorkspaceApi, WorkspaceId, WorkspaceView,
  CommandsApi, CommandDescriptor, SkillsApi, SkillEntry,
  ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
-  ModelReasoningEffort, ModelTarget, QueueAction, QueuedInboxItem, SessionModels,
+  ModelReasoningEffort, ModelSelection, QueueAction, QueuedInboxItem, SessionModels,
  GoalsApi, GoalRef,
  SettingsApi, SettingsNamespaceView, SettingsPathOpView, SettingsSecretView,
  CredentialsApi, CredentialView, ConfigurableProviderView, DiscoveredModelView, LlmApi,
--- a/packages/client/connection/src/client/fixture.ts
+++ b/packages/client/connection/src/client/fixture.ts
@@ -30,7 +30,7 @@ import type { CommandId } from '@deepseek-ai/dsh-commands/brand'
 import { deriveEventMessage, foldSurface } from '@deepseek-ai/dsh-session/surface'
 import type {
  ApiProxy, ClientRequest, ClientResponse, HistoryEntry, HostFrame, MuxFrame, RpcReceipt,
-  ModelProviderGroup, ModelTarget, RpcRequest, RpcResponse, RpcResult, ServerRequest, ServerResponse, SessionSummary,
+  ModelProviderGroup, ModelSelection, RpcRequest, RpcResponse, RpcResult, ServerRequest, ServerResponse, SessionSummary,
  ToolCallView, ToolEventView, ToolResultView, WorkspaceId, WorkspaceView,
 } from './api.ts'
 import type { RequestPayload, ResponseValue, RpcMethodMap } from '@deepseek-ai/dsh-host-apiproxy/api'
@@ -1347,7 +1347,7 @@ function createFixtureWorld(options: FixtureOptions): FixtureWorld {
    { sessionId: sid('fx-gamma'), updatedAt: Date.now() - 120_000, running: false, blank: false, cwd: '/tmp/fixture' },
  ]
  const logs = new Map<SessionId, SessionEvent[]>([[sid('fx-alpha'), buildAlphaLog()]])
-  const modelTargets = new Map<SessionId, ModelTarget>(sessions.map(session => [
+  const modelSelections = new Map<SessionId, ModelSelection>(sessions.map(session => [
    session.sessionId,
    { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
  ]))
@@ -1989,7 +1989,7 @@ function createFixtureWorld(options: FixtureOptions): FixtureWorld {
          sessionId: requestedId ?? sid(`fx-${nextSession++}`), updatedAt: Date.now(), running: false, blank: true, cwd,
        }
        sessions.push(created)
-        modelTargets.set(created.sessionId, { provider: 'deepseek-official', model: 'deepseek-v4-flash' })
+        modelSelections.set(created.sessionId, { provider: 'deepseek-official', model: 'deepseek-v4-flash' })
        attachedSessions += 1
        const emitSession = (): void => {
          // Mirrors the host: the frame fires at creation, so blank is constantly true.
@@ -2098,7 +2098,7 @@ function createFixtureWorld(options: FixtureOptions): FixtureWorld {
        return ok(request, { ...page, ...projections === undefined ? {} : { projections } })
      },
      models: request => ok(request, {
-        current: modelTargets.get(request.payload.sessionId)
+        current: modelSelections.get(request.payload.sessionId)
          ?? { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
        // The fixture's routes all serve; a surface exercising the blocked
        // posture drives it through its own stub.
@@ -2107,14 +2107,14 @@ function createFixtureWorld(options: FixtureOptions): FixtureWorld {
        failures: [],
      }),
      selectModel: (request) => {
-        const selected: ModelTarget = {
+        const selected: ModelSelection = {
          provider: request.payload.provider,
          model: request.payload.model,
          ...request.payload.reasoningEffort === undefined
            ? {}
            : { reasoningEffort: request.payload.reasoningEffort },
        }
-        modelTargets.set(request.payload.sessionId, selected)
+        modelSelections.set(request.payload.sessionId, selected)
        return ok(request, { selected })
      },
      prompt: (request) => {
@@ -2153,11 +2153,11 @@ function createFixtureWorld(options: FixtureOptions): FixtureWorld {
        // Capacity parallel of the host token-meter's request/context record:
        // log-only, appended inside the open turn, and deduplicated against the
        // route already recorded (the fixture never varies contextWindow).
-        const target = modelTargets.get(id) ?? { provider: 'deepseek', model: 'deepseek-v4-flash' }
-        if (lastRequestContext(logOf(id))?.model !== target.model) {
+        const selection = modelSelections.get(id) ?? { provider: 'deepseek', model: 'deepseek-v4-flash' }
+        if (lastRequestContext(logOf(id))?.model !== selection.model) {
          append(id, {
            type: 'request/context',
-            data: { provider: target.provider, model: target.model, contextWindow: 128_000 },
+            data: { provider: selection.provider, model: selection.model, contextWindow: 128_000 },
          })
        }
        startReply(
@@ -2167,9 +2167,9 @@ function createFixtureWorld(options: FixtureOptions): FixtureWorld {
            ? MARKDOWN_FIXTURE
            : userText === 'report model'
              ? (() => {
-                const target = modelTargets.get(id)
-                return `当前模型：${target?.provider ?? 'unknown'}/${target?.model ?? 'unknown'}`
-                  + (target?.reasoningEffort === undefined ? '' : ` · 推理等级：${target.reasoningEffort}`)
+                const selection = modelSelections.get(id)
+                return `当前模型：${selection?.provider ?? 'unknown'}/${selection?.model ?? 'unknown'}`
+                  + (selection?.reasoningEffort === undefined ? '' : ` · 推理等级：${selection.reasoningEffort}`)
              })()
              : `回声：${userText}。这是 fixture 的流式回复，用于验证打字机增长与定稿切换。`,
        )
--- a/packages/client/connection/src/client/index.ts
+++ b/packages/client/connection/src/client/index.ts
@@ -20,7 +20,7 @@ export type {
  ToolCallView, ToolResultView, WorkspaceApi, WorkspaceId, WorkspaceView,
  CommandsApi, CommandDescriptor, SkillsApi, SkillEntry,
  ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
-  MessageId, ModelReasoningEffort, ModelTarget, QueueAction, QueuedInboxItem, SessionModels,
+  MessageId, ModelReasoningEffort, ModelSelection, QueueAction, QueuedInboxItem, SessionModels,
  SubagentsApi, SubagentAddress, SubagentCatalog, SubagentListEntry, SubagentPromptReceipt,
  RpcRequest, RpcResponse, RpcResult, RpcError, RpcErrorCode,
  ClientRequest, ServerResponse, ServerRequest, ClientResponse, RpcMessage, RpcReceipt,
--- a/packages/client/connection/tests/fake-api.ts
+++ b/packages/client/connection/tests/fake-api.ts
@@ -3,7 +3,7 @@
 // deferred-controlled timing). Streams are hand pumps: pushMux/pushHost.
 import type { CommandId } from '@deepseek-ai/dsh-commands/brand'
 import type {
-  CommandDescriptor, HostFrame, IApiClient, ModelTarget, MuxFrame,
+  CommandDescriptor, HostFrame, IApiClient, ModelSelection, MuxFrame,
  RpcRequest, RpcResponse, SessionId, SessionModels, SessionSearchItem, SkillEntry,
 } from '../src/client/api.ts'
 import { RpcId } from '../src/client/api.ts'
@@ -50,11 +50,11 @@ export class FakeApiClient implements IApiClient {
  onRename: (payload: unknown) => Promise<RpcResponse<{ title: string; seq: number }>> = () => Promise.resolve(ok({ title: 'fk-renamed', seq: 0 }))
  onFork: (payload: unknown) => Promise<RpcResponse<{ sessionId: SessionId }>> = () => Promise.resolve(ok({ sessionId: 'fk-fork' as SessionId }))
  onHistory: (payload: { sessionId: SessionId; beforeSeq?: number; maxMessages?: number })
-  => Promise<RpcResponse<{ events: never[]; hasMore: boolean; modelTarget: ModelTarget }>> =
+  => Promise<RpcResponse<{ events: never[]; hasMore: boolean; modelSelection: ModelSelection }>> =
    () => Promise.resolve(ok({
      events: [],
      hasMore: false,
-      modelTarget: { provider: 'deepseek-official', model: 'deepseek-chat' },
+      modelSelection: { provider: 'deepseek-official', model: 'deepseek-chat' },
    }))

  onModels: (payload: unknown) => Promise<RpcResponse<SessionModels>> = () => Promise.resolve(ok({
@@ -63,8 +63,8 @@ export class FakeApiClient implements IApiClient {
    groups: [],
    failures: [],
  }))
-  onSelectModel: (payload: ModelTarget & { sessionId: SessionId })
-  => Promise<RpcResponse<{ selected: ModelTarget }>> =
+  onSelectModel: (payload: ModelSelection & { sessionId: SessionId })
+  => Promise<RpcResponse<{ selected: ModelSelection }>> =
    payload => Promise.resolve(ok({ selected: { provider: payload.provider, model: payload.model } }))
  onPrompt: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
  onUpdateQueue: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
@@ -105,7 +105,7 @@ export class FakeApiClient implements IApiClient {
    history: (payload: { sessionId: SessionId; beforeSeq?: number; maxMessages?: number }) =>
      this.record('session.history', payload, this.onHistory(payload)),
    models: (payload: unknown) => this.record('session.models', payload, this.onModels(payload)),
-    selectModel: (payload: ModelTarget & { sessionId: SessionId }) =>
+    selectModel: (payload: ModelSelection & { sessionId: SessionId }) =>
      this.record('session.selectModel', payload, this.onSelectModel(payload)),
    rename: (payload: unknown) => this.record('session.rename', payload, this.onRename(payload)),
    fork: (payload: unknown) => this.record('session.fork', payload, this.onFork(payload)),
--- a/packages/client/connection/tests/fixture.spec.ts
+++ b/packages/client/connection/tests/fixture.spec.ts
@@ -168,7 +168,7 @@ describe('createFixtureApi', () => {
    })
  })

-  it('serves grouped models and keeps a selected target for later history and fixture requests', async () => {
+  it('serves grouped models and keeps a selection for later history and fixture requests', async () => {
    const api = createFixtureApi()
    const sessionId = sid('fx-alpha')
    const catalog = await api.sessions.models(req({ sessionId }))
--- a/packages/client/runtime/README.i18n.yaml
+++ b/packages/client/runtime/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/runtime/README.md
-README.md: a9b604974595b1b7856f74b72d36093491ec1bd1
-README.zh.md: 41c81532667f445ce1c52e1b84185ef503e82141
+README.md: c2ce461439a89aa4fe2d59ebf92d14539479dac8
+README.zh.md: bca93b80989152eccccaf13c0f31435c91e7393c
--- a/packages/client/runtime/README.md
+++ b/packages/client/runtime/README.md
@@ -62,7 +62,7 @@ The Session object validates plugin-owned, provider-routed `llm/retry` payloads

 ## Session model selection

-Each resident `Session` owns a `modelSelection` snapshot containing the current provider/model target, provider-grouped directory, provider-local failures, and the `idle`/`loading`/`ready`/`selecting`/`error` state. History establishes or refreshes the current target, opening a selector refreshes the directory, and selection failures preserve the last target and usable groups. Directory and selection operations share a monotonically increasing generation so an older response cannot overwrite a newer selection. A reconnect rebuild restores the target reported by the Host without replacing unchanged selection substructure.
+Each resident `Session` owns a `modelSelection` snapshot containing the current `ModelSelection`, provider-grouped directory, provider-local failures, and the `idle`/`loading`/`ready`/`selecting`/`error` state. History establishes or refreshes the current selection, opening a selector refreshes the directory, and selection failures preserve the last selection and usable groups. Directory and selection operations share a monotonically increasing generation so an older response cannot overwrite a newer selection. A reconnect rebuild restores the selection reported by the Host without replacing unchanged selection substructure.

 ## Model Experience

@@ -70,7 +70,7 @@ None, as the session object layer selects the provider/model route used by a lat

 #### KV Cache effect

-Changing the target can change or invalidate provider-side cache reuse; this package does not alter the prompt prefix itself.
+Changing the model selection can change or invalidate provider-side cache reuse; this package does not alter the prompt prefix itself.

 ## Known Limitations and Deferred Work

--- a/packages/client/runtime/README.zh.md
+++ b/packages/client/runtime/README.zh.md
@@ -62,7 +62,7 @@ Session 对象会在事件 wire 边界依据生产方的完整字段约定，验

 ## 会话模型选择

-每个常驻 `Session` 都拥有一个 `modelSelection` 快照，其中包含当前提供方/模型目标、按提供方分组的目录、逐提供方失败记录，以及 `idle`／`loading`／`ready`／`selecting`／`error` 状态。历史记录会建立或刷新当前目标，打开选择器会刷新目录；选择失败会保留上一个目标和可用分组。目录与选择操作共用单调递增的代次，因此较旧响应无法覆盖较新的选择。重连重建会恢复 Host 报告的目标，同时不替换未变化的选择子结构。
+每个常驻 `Session` 都拥有一个 `modelSelection` 快照，其中包含当前 `ModelSelection`、按提供方分组的目录、逐提供方失败记录，以及 `idle`／`loading`／`ready`／`selecting`／`error` 状态。历史记录会建立或刷新当前选择，打开选择器会刷新目录；选择失败会保留上一个选择和可用分组。目录与选择操作共用单调递增的代次，因此较旧响应无法覆盖较新的选择。重连重建会恢复 Host 报告的选择，同时不替换未变化的选择子结构。

 ## 模型体验

@@ -70,7 +70,7 @@ Session 对象会在事件 wire 边界依据生产方的完整字段约定，验

 #### KV Cache 影响

-更改目标可能改变提供方侧的缓存复用，或使其失效；该包本身不会改变提示词前缀。
+更改模型选择可能改变提供方侧的缓存复用，或使其失效；该包本身不会改变提示词前缀。

 ## 已知限制与暂缓事项

--- a/packages/client/runtime/tests/fake-api.ts
+++ b/packages/client/runtime/tests/fake-api.ts
@@ -3,7 +3,7 @@
 // deferred-controlled timing). Streams are hand pumps: pushMux/pushHost.
 import type { CommandId } from '@deepseek-ai/dsh-commands/brand'
 import type {
-  ClientResponse, CommandDescriptor, HostFrame, IApiClient, ModelTarget, MuxFrame,
+  ClientResponse, CommandDescriptor, HostFrame, IApiClient, ModelSelection, MuxFrame,
  RpcError, RpcReceipt, RpcRequest, RpcResponse, SessionId, SessionModels, SessionSearchItem, SkillEntry,
  WorkspaceId, WorkspaceView,
 } from '@deepseek-ai/dsh-client-connection/client'
@@ -64,7 +64,7 @@ export class FakeApiClient implements IApiClient {
  onSearch: (payload: unknown) => Promise<RpcResponse<{ items: SessionSearchItem[]; hasMore: boolean }>> =
    () => Promise.resolve(ok({ items: [], hasMore: false }))
  onCreate: (payload: unknown) => Promise<RpcResponse<{ sessionId: SessionId }>> = () => Promise.resolve(ok({ sessionId: 'fk-new' as SessionId }))
-  readonly defaultModel: ModelTarget = { provider: 'deepseek-official', model: 'deepseek-v4-flash' }
+  readonly defaultModel: ModelSelection = { provider: 'deepseek-official', model: 'deepseek-v4-flash' }
  onRename: (payload: unknown) => Promise<RpcResponse<{ title: string; seq: number }>> = () => Promise.resolve(ok({ title: 'fk-renamed', seq: 0 }))
  onFork: (payload: unknown) => Promise<RpcResponse<{ sessionId: SessionId }>> = () => Promise.resolve(ok({ sessionId: 'fk-fork' as SessionId }))
  onHistory: (payload: { sessionId: SessionId; beforeSeq?: number; maxMessages?: number })
@@ -82,7 +82,7 @@ export class FakeApiClient implements IApiClient {
    failures: [],
  }))
  onSelectModel: (payload: { provider: string; model: string }) =>
-  Promise<RpcResponse<{ selected: ModelTarget }>> =
+  Promise<RpcResponse<{ selected: ModelSelection }>> =
    payload => Promise.resolve(ok({ selected: { provider: payload.provider, model: payload.model } }))
  onPrompt: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
  onUpdateQueue: (payload: unknown) => Promise<RpcResponse<{ accepted: true }>> = () => Promise.resolve(ok({ accepted: true as const }))
--- a/packages/client/runtime/tests/manager.spec.ts
+++ b/packages/client/runtime/tests/manager.spec.ts
@@ -842,7 +842,7 @@ describe('connected generation', () => {
    api.onHistory = () => Promise.resolve(ok({
      events: entries(plainTurn(0, 0, 'a', 'b')) as never[],
      hasMore: false,
-      modelTarget: { provider: 'deepseek-official', model: 'deepseek-chat' },
+      modelSelection: { provider: 'deepseek-official', model: 'deepseek-chat' },
    }))
    const manager = new SessionManager(api)
    const openedSession = manager.get(S1)
--- a/packages/client/runtime/tests/session.spec.ts
+++ b/packages/client/runtime/tests/session.spec.ts
@@ -89,7 +89,7 @@ describe('open', () => {
    gate.resolve(ok({
      events: entries(page) as never[],
      hasMore: false,
-      modelTarget: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
+      modelSelection: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
    }))
    await opening
    const seqs = session.getSnapshot().nodes.map(n => n.seq)
@@ -631,7 +631,7 @@ describe('paging', () => {
    gate.resolve(ok({
      events: entries(plainTurn(0, 0, 'a', 'b')) as never[],
      hasMore: false,
-      modelTarget: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
+      modelSelection: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
    }))
    await Promise.all([first, second])
    expect(api.callsOf('session.history')).toHaveLength(2) // open + one page, not two
@@ -1018,7 +1018,7 @@ describe('remaining branches', () => {
    stale.resolve(ok({
      events: entries(plainTurn(0, 0, '旧', '代')) as never[],
      hasMore: false,
-      modelTarget: { provider: 'deepseek-official', model: 'stale' },
+      modelSelection: { provider: 'deepseek-official', model: 'stale' },
    })) // success, but its generation is gone
    await Promise.all([opening, resynced])
    expect(session.getSnapshot().nodes.map(n => n.seq)).toEqual([7, 9]) // only the fresh generation's window
@@ -1041,7 +1041,7 @@ describe('remaining branches', () => {
    secondPull.resolve(ok({
      events: entries([...plainTurn(0, 0, 'a', 'b'), ...plainTurn(6, 1, 'c', 'd')]) as never[],
      hasMore: false,
-      modelTarget: { provider: 'deepseek-official', model: 'stale' },
+      modelSelection: { provider: 'deepseek-official', model: 'stale' },
    }))
    await Promise.all([opening, resynced])
    expect(session.getSnapshot().openState).toBe('open')
@@ -1059,7 +1059,7 @@ describe('remaining branches', () => {
    repairPull.resolve(ok({
      events: entries(plainTurn(0, 0, '旧', '页')) as never[],
      hasMore: false,
-      modelTarget: { provider: 'deepseek-official', model: 'stale' },
+      modelSelection: { provider: 'deepseek-official', model: 'stale' },
    })) // repair result: stale, dropped
    await resynced
    expect(session.getSnapshot().nodes.map(n => n.seq)).toEqual([7, 9])
@@ -1104,7 +1104,7 @@ describe('remaining branches', () => {
        { event: ev.toolResult(7, 1, 'h1', 'done'), view: { for: 'result', view: { card: 'generic', title: '历史果' } } },
      ] as never[],
      hasMore: false,
-      modelTarget: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
+      modelSelection: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
    }))
    await session.open()
    expect(session.getSnapshot().nodes.at(-1)).toMatchObject({
--- a/packages/client/ui-model/README.i18n.yaml
+++ b/packages/client/ui-model/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/ui-model/README.md
-README.md: 5a6f998476629566d35af32efa5d8bc5072a872b
-README.zh.md: 55ea296370ffa986c9b11b41f83ef83b12236e88
+README.md: b37f807944850fb34331cd8d78b4a2ccf157f21c
+README.zh.md: 906096bed06af26517e215b2d1e1da4b62e58095
--- a/packages/client/ui-model/README.md
+++ b/packages/client/ui-model/README.md
@@ -4,7 +4,7 @@ English | [中文](README.zh.md)

 Model selection plugin, browser half: TWO entries over ONE per-session directory owned by `ModelService` (`ctx.models`). For ordinary sessions, the `/model` popupSelect contribution (registered through `ctx.command`) and the composer's named `conversation.input.model` seat both load the session's advisory directory through `session.models` and submit through `session.selectModel` via the same `ModelDirectory` instance. The compact composer trigger opens a two-level Model/Effort menu: models stay provider-grouped, while the selected exact model supplies its adapter-owned effort names, descriptions, and default. `/model` applies the selected model's default effort, and the composer can then choose any advertised effort.

-The Host-reported provider/model/reasoning target is the single selection fact, but it is echoed only when the exact route remains in the advertised groups; removing that catalog row leaves the routable target intact while the trigger prompts `Select model`, no stale row is synthesized, and no Effort row is shown until the user picks an advertised model. Directory loads and selections share a generation counter so an older response never overwrites a newer one; a connection reset drops every resident projection and repulls the Host-restored target before display. Provider-local metadata failures list inline while usable groups stay selectable, and selection failures retain the prior target and directory.
+The Host-reported provider/model/reasoning `ModelSelection` is the single selection fact, but it is echoed only when the exact provider/model pair remains in the advertised groups; an absent catalog row leaves the routable selection intact while the trigger prompts `Select model`, no stale row is synthesized, and no Effort row is shown until the user picks an advertised model. Directory loads and selections share a generation counter so an older response never overwrites a newer one; a connection reset drops every resident projection and repulls the Host-restored selection before display. Provider-local metadata failures list inline while usable groups stay selectable, and selection failures retain the prior selection and directory.

 When the Host reports that no adapter serves the session's route (`session.models.routable`), this plugin raises a composer block through `ctx.conversation.blocks` and the input goes inert with this plugin's own copy; recovering clears it without a reload. It follows `routable` and nothing else: a `null` — before the first load, or after one failed — never blocks, or a slow Host would lock a working composer, and catalog membership never blocks either, because a route serving a model it stopped advertising is missing from the groups yet perfectly usable. The trigger's own `Select model` fallback still covers that case, which is display, not a gate.

@@ -14,7 +14,7 @@ The `/client` export surface is the plugin body (`apply`/`inject`), `ModelServic

 ## Model Experience

-Indirectly, through the `session.selectModel` RPC available to ordinary sessions, both entries submit the provider/model/reasoning target that the Host snapshots at the next prompt-assembly boundary, so the following request uses the chosen route and effort while a running step keeps its assembled target; the selection becomes durable only when the existing request header records a request that consumes it, and menu interaction adds no prompt content.
+Indirectly, through the `session.selectModel` RPC available to ordinary sessions, both entries submit the complete `ModelSelection` that the Host snapshots at the next prompt-assembly boundary, so the following request uses the selected provider, model, and effort while a running step keeps its assembled selection; the selection becomes durable only when the existing request header records a request that consumes it, and menu interaction adds no prompt content.

 #### KV Cache effect

@@ -22,6 +22,6 @@ Switching the route can reduce or invalidate provider-side cache reuse for subse

 ## Known Limitations and Deferred Work

- **No create-time or addressed-subagent selection** — both entries require an existing ordinary session's Agent; there is no draft-phase model choice to fold into session creation, and subagent continuation deliberately exposes no independent model-retargeting contract.
+- **No create-time or addressed-subagent selection** — both entries require an existing ordinary session's Agent; there is no draft-phase model choice to fold into session creation, and subagent continuation deliberately exposes no independent model-selection contract.
 - **Directory names are presentation-only** — selection and persistence use provider/model/effort ids; a provider whose catalog or exact-model metadata lookup fails lists as an unselectable failure row until reload.
 - **No arbitrary effort input** — the composer offers only the exact model's adapter-advertised levels; an adapter without reasoning metadata leaves the Effort row absent.
--- a/packages/client/ui-model/README.zh.md
+++ b/packages/client/ui-model/README.zh.md
@@ -4,7 +4,7 @@

 模型选择插件（浏览器侧）：**两个入口共用一份会话级目录**，由 `ModelService`（`ctx.models`）持有。对于普通会话，`/model` popupSelect 贡献项（经 `ctx.command` 注册）与 composer 的具名 `conversation.input.model` slot 都通过同一个 `ModelDirectory` 实例，经 `session.models` 加载会话的建议目录，并经 `session.selectModel` 提交。紧凑型 composer 触发器会打开两级 Model/Effort 菜单：模型仍按提供方分组，所选具体模型则提供由其适配器持有的推理强度名称、说明和默认值。`/model` 应用所选模型的默认推理强度，composer 随后可以选择任一已公布的推理强度。

-Host 报告的提供方／模型／推理（reasoning）目标是唯一的选择事实，但只有当该精确路由仍在已公布分组中时才会回显；删除该目录行会保留仍可路由的目标，但触发器会提示 `Select model`，系统不会合成陈旧行，且在用户选择已公布的模型之前不会显示 Effort 行。目录加载与选择共享一个代次计数器，旧响应不会覆盖新结果；连接重置会丢弃所有常驻目录投影，并在显示前重新拉取 Host 恢复的目标。各提供方的元数据获取失败会内联列出，同时可用分组仍可选择；选择失败会保留先前的目标和目录。
+Host 报告的 `ModelSelection` 是唯一的选择事实，其中包含提供方、模型与推理（reasoning）强度；但只有当该提供方／模型对仍在已公布分组中时才会回显。目录行缺席时，可路由的选择保持不变，但触发器会提示 `Select model`；系统不会合成陈旧行，且在用户选择已公布的模型之前不会显示 Effort 行。目录加载与选择共享一个代次计数器，旧响应不会覆盖新结果；连接重置会丢弃所有常驻目录投影，并在显示前重新拉取 Host 恢复的选择。各提供方的元数据获取失败会内联列出，同时可用分组仍可选择；选择失败会保留先前的选择和目录。

 当宿主报告没有适配器服务该会话的路由（`session.models.routable`）时，本插件经 `ctx.conversation.blocks` 注册一个 composer 阻塞块，输入框随之停用并显示本插件自己的文案；恢复后无需重新加载即自动清除。它只跟随 `routable`：`null`（首次加载之前，或加载失败之后）绝不阻断，否则一个慢的宿主就会锁死一个本来可用的 composer；目录成员关系同样不阻断，因为一条仍在服务、只是不再公布该模型的路由不在分组里，却完全可用。触发器自己的 `Select model` 回退仍然覆盖那种情形——那是显示，不是闸门。

@@ -14,7 +14,7 @@ Host 报告的提供方／模型／推理（reasoning）目标是唯一的选择

 ## 模型体验

-间接影响。两个入口都通过仅供普通会话使用的 `session.selectModel` RPC 提交提供方／模型／推理强度目标；Host 会在下一次提示词组装边界对该目标进行快照，因此后续请求采用所选路由和推理强度，而运行中的步骤保留已组装目标。只有当现有请求头记录一次实际采用该选择的请求后，选择才会持久化；菜单交互不会添加提示词内容。
+间接影响。两个入口都通过仅供普通会话使用的 `session.selectModel` RPC 提交完整的 `ModelSelection`；Host 会在下一次提示词组装边界对其进行快照，因此后续请求采用所选提供方、模型与推理强度，而运行中的步骤保留已组装选择。只有当现有请求头记录一次实际采用该选择的请求后，选择才会持久化；菜单交互不会添加提示词内容。

 #### KV Cache 影响

@@ -22,6 +22,6 @@ Host 报告的提供方／模型／推理（reasoning）目标是唯一的选择

 ## 已知限制与暂缓事项

- **无创建期或已寻址 subagent 选择**——两个入口都要求既有普通会话的 agent；没有可纳入会话创建的草稿阶段模型选择，subagent 继续执行也有意不公开独立更改模型目标的约定。
+- **无创建期或已寻址 subagent 选择**——两个入口都要求既有普通会话的 agent；没有可纳入会话创建的草稿阶段模型选择，subagent 继续执行也有意不公开独立的模型选择约定。
 - **目录名仅供呈现**——选择与持久化使用提供方／模型／推理强度 id；目录查询或确切模型元数据查询失败的提供方以不可选失败行列出，重新加载前保持原样。
 - **不能任意输入推理强度**——composer 仅提供确切模型由适配器公布的推理强度；适配器没有推理元数据时不显示 Effort 行。
--- a/packages/client/ui-model/src/client/ModelSelect.tsx
+++ b/packages/client/ui-model/src/client/ModelSelect.tsx
@@ -14,7 +14,7 @@ import {
  type KeyboardEvent, type FocusEvent,
 } from 'react'
 import clsx from 'clsx'
-import type { ModelReasoningEffort, ModelTarget } from '@deepseek-ai/dsh-client-connection/client'
+import type { ModelReasoningEffort, ModelSelection } from '@deepseek-ai/dsh-client-connection/client'
 import {
  IconCheckOutline16, IconChevronDownOutline14, IconChevronRightOutline14,
 } from '@deepseek-ai/dsh-client-ui-primitives'
@@ -58,17 +58,17 @@ export function ModelSelect(
    group.models.map(model => ({
      group,
      model,
-      target: {
+      selection: {
        provider: group.id,
        model: model.id,
        ...model.reasoning?.defaultEffort === undefined
          ? {}
          : { reasoningEffort: model.reasoning.defaultEffort },
-      } satisfies ModelTarget,
+      } satisfies ModelSelection,
    }))), [state.groups])
  const selectedIndex = state.current === null
    ? -1
-    : choices.findIndex(c => c.target.provider === state.current?.provider && c.target.model === state.current.model)
+    : choices.findIndex(c => c.selection.provider === state.current?.provider && c.selection.model === state.current.model)
  const currentChoice = choices[selectedIndex]
  const reasoning = currentChoice?.model.reasoning
  const effectiveEffort = state.current?.reasoningEffort ?? reasoning?.defaultEffort
@@ -148,12 +148,12 @@ export function ModelSelect(
    close()
  }

-  const choose = (target: ModelTarget): void => {
-    if (state.current?.provider === target.provider && state.current.model === target.model) {
+  const choose = (selection: ModelSelection): void => {
+    if (state.current?.provider === selection.provider && state.current.model === selection.model) {
      close(true)
      return
    }
-    void select(target).then((accepted) => {
+    void select(selection).then((accepted) => {
      if (accepted && rootRef.current !== null) close(true)
    })
  }
@@ -164,12 +164,12 @@ export function ModelSelect(
      close(true)
      return
    }
-    const target: ModelTarget = {
+    const selection: ModelSelection = {
      provider: state.current.provider,
      model: state.current.model,
      ...effort === undefined ? {} : { reasoningEffort: effort },
    }
-    void select(target).then((accepted) => {
+    void select(selection).then((accepted) => {
      if (accepted && rootRef.current !== null) close(true)
    })
  }
--- a/packages/client/ui-model/src/client/directory.ts
+++ b/packages/client/ui-model/src/client/directory.ts
@@ -6,17 +6,17 @@
 * either entry is what the other shows next.
 */
 import type {
-  IApiClient, ModelCatalogFailure, ModelProviderGroup, ModelTarget, SessionId, SessionModels,
+  IApiClient, ModelCatalogFailure, ModelProviderGroup, ModelSelection, SessionId, SessionModels,
 } from '@deepseek-ai/dsh-client-connection/client'
 import type { SnapshotStore } from '@deepseek-ai/dsh-client-runtime/client'
 import { createSnapshotStore } from '@deepseek-ai/dsh-client-runtime/client'

 /** Directory snapshot both entries render from. */
 export interface ModelDirectoryState {
-  /** Target the host reports for the next assembled step; null before the first load. */
-  current: ModelTarget | null
+  /** Model selection the host reports for the next assembled step; null before the first load. */
+  current: ModelSelection | null
  /**
-   * Whether an adapter serves the current target's route, as the host reports
+   * Whether an adapter serves the current selection's provider, as the host reports
   * it — null before the first load, which is NOT the same as blocked. Read
   * this rather than "current matches no group": catalog membership is
   * advisory, so a route serving a model it stopped advertising is missing
@@ -57,7 +57,7 @@ export class ModelDirectory {

  /**
   * Refresh the advisory directory (both entries call this on open).
-   * Failure preserves the last good groups and current target.
+   * Failure preserves the last good groups and current selection.
   * @returns the fresh directory value.
   */
  async load(): Promise<SessionModels> {
@@ -86,22 +86,22 @@ export class ModelDirectory {
  }

  /**
-   * Select the complete provider/model/reasoning target (both entries submit through here). Success
+   * Select the complete provider/model/reasoning selection (both entries submit through here). Success
   * updates the shared current; failure surfaces on the store and throws so
   * each entry's own retry surface engages.
-   * @param target - provider, provider-owned model id, and optional adapter-owned effort.
-   */
-  async select(target: ModelTarget): Promise<void> {
+   * @param selection - provider, provider-owned model id, and optional adapter-owned effort.
+ */
+  async select(selection: ModelSelection): Promise<void> {
    this.assertAvailable()
    const generation = ++this.generation
    this.store.update((s) => { s.status = 'selecting'; s.error = null })
    const { result } = await this.sessions.selectModel({
      sessionId: this.sessionId,
-      provider: target.provider,
-      model: target.model,
-      ...target.reasoningEffort === undefined
+      provider: selection.provider,
+      model: selection.model,
+      ...selection.reasoningEffort === undefined
        ? {}
-        : { reasoningEffort: target.reasoningEffort },
+        : { reasoningEffort: selection.reasoningEffort },
    })
    if (this.disposed || generation !== this.generation) {
      if (!result.ok) throw new Error(`${result.error.code}: ${result.error.message}`)
@@ -124,7 +124,7 @@ export class ModelDirectory {
  /**
   * Drop the previous Host generation's projection and repull it. Clearing
   * first prevents an unconsumed process-local selection from being displayed
-   * while the restarted Host has restored the last logged request target.
+   * while the restarted Host has restored the last logged model selection.
   */
  resetConnected(): void {
    if (this.disposed) return
--- a/packages/client/ui-model/src/client/index.ts
+++ b/packages/client/ui-model/src/client/index.ts
@@ -4,14 +4,14 @@
 * contribution and the composer's named `conversation.input.model` seat both
 * load the session's provider-grouped advisory directory (`session.models`)
 * and submit through `session.selectModel` via the same directory instance,
- * so the host-reported current target is the single fact both surfaces echo
+ * so the host-reported current selection is the single fact both surfaces echo
 * — a switch made in either entry is what the other shows next. Failures
 * ride each entry's own retry surface (popup shell error/retry; seat menu
 * inline error) without forking the state. Addressed subagent sessions expose
 * neither entry because those Agent-bound RPCs would activate persisted
 * history outside the direct-parent continuation seam.
 */
-import type { ModelTarget, SessionModels } from '@deepseek-ai/dsh-client-connection/client'
+import type { ModelSelection, SessionModels } from '@deepseek-ai/dsh-client-connection/client'
 import type { ClientContext } from '@deepseek-ai/dsh-client-runtime/client'
 import type { CommandServiceContract, SelectOption } from '@deepseek-ai/dsh-client-ui-command/client'
 // Type-only: pulls the ui-conversation SlotMap merge (the input.model seat).
@@ -68,13 +68,13 @@ function optionsOf(directory: SessionModels, t: TranslateNS<'model'>): SelectOpt
 }

 /**
- * Resolve a picked row back to its target by matching against the loaded
+ * Resolve a picked row back to its model selection by matching against the loaded
 * groups (the same data the rows were built from — ids stay opaque).
 * @param state - the session's directory snapshot.
 * @param id - the picked row id.
- * @returns the row's target, or undefined for failure rows / stale ids.
+ * @returns the row's model selection, or undefined for failure rows / stale ids.
 */
-function targetOf(state: ModelDirectoryState, id: string): ModelTarget | undefined {
+function selectionOf(state: ModelDirectoryState, id: string): ModelSelection | undefined {
  for (const group of state.groups) {
    for (const model of group.models) {
      if (rowId(group.id, model.id) !== id) continue
@@ -139,11 +139,11 @@ export function apply(ctx: ClientContext): void {
            throw new Error('model selection is unavailable for addressed subagent sessions')
          }
          const directory = models.directoryFor(session.sessionId)
-          const target = targetOf(directory.store.getSnapshot(), option.id)
-          if (target === undefined) {
+          const selection = selectionOf(directory.store.getSnapshot(), option.id)
+          if (selection === undefined) {
            throw new Error('this provider\'s catalog failed to load — pick a model from a loaded group')
          }
-          await directory.select(target)
+          await directory.select(selection)
        },
      },
    }), 'ui-model: /model contribution')
@@ -165,8 +165,8 @@ export function apply(ctx: ClientContext): void {
          load: () => {
            if (available) directory.load().catch(() => { /* surfaced on the store */ })
          },
-          select: (target: ModelTarget) => available
-            ? directory.select(target).then(() => true, () => false)
+          select: (selection: ModelSelection) => available
+            ? directory.select(selection).then(() => true, () => false)
            : Promise.resolve(false),
        }
      },
--- a/packages/client/ui-model/src/client/slots.ts
+++ b/packages/client/ui-model/src/client/slots.ts
@@ -4,7 +4,7 @@
 * entry; this package only contributes the single occupant, so no SlotMap
 * merge lives here.
 */
-import type { ModelTarget } from '@deepseek-ai/dsh-client-connection/client'
+import type { ModelSelection } from '@deepseek-ai/dsh-client-connection/client'
 import type { SnapshotStore } from '@deepseek-ai/dsh-client-runtime/client'
 import type { ModelDirectoryState } from './directory.ts'

@@ -17,9 +17,9 @@ export interface ModelSelectInjected {
  /** Refresh the advisory directory (fire-and-forget; errors land on the store). */
  load: () => void
  /**
-   * Select a complete provider/model/reasoning target through the shared route.
-   * @param target - model target and optional adapter-owned effort.
+   * Select a complete provider/model/reasoning selection.
+   * @param selection - model selection and optional adapter-owned effort.
   * @returns whether the host accepted the selection.
   */
-  select: (target: ModelTarget) => Promise<boolean>
+  select: (selection: ModelSelection) => Promise<boolean>
 }
--- a/packages/client/ui-model/tests/browser-plugin.spec.ts
+++ b/packages/client/ui-model/tests/browser-plugin.spec.ts
@@ -13,7 +13,7 @@ import { describe, expect, it } from 'vitest'
 import { createScope } from '@deepseek-ai/dsh-client-runtime/client'
 import type { SessionId } from '@deepseek-ai/dsh-client-runtime/client'
 import { LocaleService } from '@deepseek-ai/dsh-client-locale/client'
-import type { ModelTarget } from '@deepseek-ai/dsh-client-connection/client'
+import type { ModelSelection } from '@deepseek-ai/dsh-client-connection/client'
 import type { CommandContribution, SelectOption } from '@deepseek-ai/dsh-client-ui-command/client'
 import type { ModelSelectInjected } from '../src/client/slots.ts'
 import { apply, inject } from '../src/client/index.ts'
@@ -55,7 +55,7 @@ const GROUPS = [{
 /** Boot the plugin over fake faces + a stateful fake host (current moves on selectModel). */
 async function bench() {
  const ctx = new Context()
-  let current: ModelTarget = { provider: 'deepseek-official', model: 'deepseek-v4-flash' }
+  let current: ModelSelection = { provider: 'deepseek-official', model: 'deepseek-v4-flash' }
  const calls = { models: 0, select: 0 }
  ctx.provide('connection', { api: { sessions: {
    models: () => {
@@ -125,7 +125,7 @@ async function bench() {
    contribution: () => contribution!,
    seat: () => seats.get('conversation.input.model')!,
    hostCurrent: () => current,
-    setHostCurrent: (target: ModelTarget) => { current = target },
+    setHostCurrent: (selection: ModelSelection) => { current = selection },
    address: (id: SessionId) => { addressed.add(id) },
    setRoutable: (next: boolean) => { routable = next },
    blockOf: (key: string) => blocks.get(sid(key)),
--- a/packages/client/ui-model/tests/model-select.spec.tsx
+++ b/packages/client/ui-model/tests/model-select.spec.tsx
@@ -1,7 +1,7 @@
 // @vitest-environment jsdom
 import { cleanup, fireEvent, render, screen, waitFor } from '@testing-library/react'
 import { afterEach, describe, expect, it, vi } from 'vitest'
-import type { ModelTarget } from '@deepseek-ai/dsh-client-connection/client'
+import type { ModelSelection } from '@deepseek-ai/dsh-client-connection/client'
 import { createSnapshotStore } from '@deepseek-ai/dsh-client-runtime/client'
 import type { ComponentProps } from 'react'
 import type { ModelDirectoryState } from '../src/client/directory.ts'
@@ -48,10 +48,10 @@ function state(overrides: Partial<ModelDirectoryState> = {}): ModelDirectoryStat
 afterEach(cleanup)

 describe('ModelSelect reasoning effort', () => {
-  it('renders adapter metadata and submits the effort as part of the session target', async () => {
+  it('renders adapter metadata and submits the effort as part of the session selection', async () => {
    const directory = createSnapshotStore<ModelDirectoryState>(state())
-    const select = vi.fn(async (target: ModelTarget) => {
-      directory.set(state({ current: target }))
+    const select = vi.fn(async (selection: ModelSelection) => {
+      directory.set(state({ current: selection }))
      return true
    })
    render(<ModelSelect
@@ -112,7 +112,7 @@ describe('ModelSelect reasoning effort', () => {
      .toEqual(['Default', 'Standard'])
  })

-  it('prompts for a new selection when the current target is no longer advertised', () => {
+  it('prompts for a selection when the current model is no longer advertised', () => {
    const directory = createSnapshotStore(state({
      current: { provider: 'deepseek-official', model: 'removed-model' },
    }))
--- a/packages/core/README.i18n.yaml
+++ b/packages/core/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/core/README.md
-README.md: 40a888183a9338805d83c86bab9ae16f1c7bc04f
-README.zh.md: c0a24d78cb8ff2a2b2ccc2d2a2f4294424be55b0
+README.md: 19aed9abafa8e4531d2ee31ff0442003328a9ef6
+README.zh.md: 73ed1f500799cb235a8835ffb0317370f9a0a7e6
--- a/packages/core/README.md
+++ b/packages/core/README.md
@@ -2,7 +2,7 @@

 English | [中文](README.zh.md)

-The session log, system-prompt assembly, tool registry, agent vocabulary, and concrete loop that form the harness's default control spine. These are **product** packages — the stable surface plugins and consumers build against.
+The session log, system-prompt assembly, tool registry, agent vocabulary, deployment-default model selection, and concrete loop that form the harness's default control spine. These are **product** packages — the stable surface plugins and consumers build against.

 | Package | Role | ctx key |
 |---|---|---|
@@ -11,9 +11,10 @@ The session log, system-prompt assembly, tool registry, agent vocabulary, and co
 | [`system-prompt/`](system-prompt/README.md) | Prompt and tool-schema assembly registry | `ctx.systemPrompt` |
 | [`tools/`](tools/README.md) | Scoped tool registry and execution pipeline | `ctx.tools` |
 | [`agent/`](agent/README.md) | Agent interface, registry, and event vocabulary | `ctx.agents` |
+| [`agent-default-model/`](agent-default-model/README.md) | Default model selection shared by Agent front doors | `ctx.agentDefaultModel` |
 | [`agent-loop/`](agent-loop/README.md) | Default concrete agent driver | `ctx.agentLoop` |

-`scope` supplies the shared scoping primitive. `agent` owns the public seam, while `agent-loop` is its default implementation; extension plugins depend on the seam so the driver remains swappable.
+`scope` supplies the shared scoping primitive. `agent` owns the public seam, while `agent-loop` is its default implementation; extension plugins depend on the seam so the driver remains swappable. `agent-default-model` owns the deployment selection an Agent front door uses only when a session has no selection of its own.

 Runnable compositions belong to [`examples/agent-spine-demo`](../examples/agent-spine-demo/README.md); this group owns only the swappable spine pieces.

--- a/packages/core/README.zh.md
+++ b/packages/core/README.zh.md
@@ -2,7 +2,7 @@

 [English](README.md) | 中文

-构成 harness 默认控制主干的会话日志、系统提示词组装、工具注册表、agent（智能体）词汇和具体循环。这些是**产品**包，即插件和消费方构建所依赖的稳定 surface。
+构成 harness 默认控制主干的会话日志、系统提示词组装、工具注册表、agent（智能体）词汇、部署默认模型选择和具体循环。这些是**产品**包，即插件和消费方构建所依赖的稳定 surface。

 | 包 | 职责 | ctx key |
 |---|---|---|
@@ -11,9 +11,10 @@
 | [`system-prompt/`](system-prompt/README.md) | 提示词和工具 schema 组装注册表 | `ctx.systemPrompt` |
 | [`tools/`](tools/README.md) | 作用域工具注册表和执行流水线 | `ctx.tools` |
 | [`agent/`](agent/README.md) | Agent 接口、注册表和事件词汇 | `ctx.agents` |
+| [`agent-default-model/`](agent-default-model/README.md) | 各 Agent 入口共享的默认模型选择 | `ctx.agentDefaultModel` |
 | [`agent-loop/`](agent-loop/README.md) | 默认具体 agent 驱动器 | `ctx.agentLoop` |

-`scope` 提供共享作用域原语。`agent` 负责公开 seam，`agent-loop` 是其默认实现；扩展插件依赖该 seam，从而保持驱动器可替换。
+`scope` 提供共享作用域原语。`agent` 负责公开 seam，`agent-loop` 是其默认实现；扩展插件依赖该 seam，从而保持驱动器可替换。`agent-default-model` 负责部署选择，Agent 入口仅在会话自身没有选择时使用它。

 可运行组合属于 [`examples/agent-spine-demo`](../examples/agent-spine-demo/README.md)；该分组只负责可替换的主干组件。

--- a/packages/core/agent-default-model/README.i18n.yaml
+++ b/packages/core/agent-default-model/README.i18n.yaml
@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write packages/core/agent-default-model/README.md
+README.md: 02bcc9be3adee2293a20b3ae87ddaf4d52e70deb
+README.zh.md: 807b612bd25e49aa318c13c8c8dc7595a6459080
--- a/packages/core/agent-default-model/README.md
+++ b/packages/core/agent-default-model/README.md
@@ -0,0 +1,25 @@
+# @deepseek-ai/dsh-agent-default-model
+
+English | [中文](README.zh.md)
+
+The deployment default used when a front door creates an Agent that has no session-local model selection. `AgentDefaultModelService` provides `ctx.agentDefaultModel`; direct front doors such as `dsh run` and Host-backed front doors such as ApiProxy read the same service instead of owning parallel provider/model defaults.
+
+The plugin config requires `{ provider, model }`. That composition entry is the base of the `agent-default-model` Settings section; a mounted settings provider layers the user's choice over it and changes are visible on the next `currentSelection()` read. `reasoningEffort` belongs to the Settings section but deliberately not to plugin config: a complete saved selection can clear an effort when the next selected model has none, while a composition value would be inherited again.
+
+- `ctx.agentDefaultModel.currentSelection()` returns a detached `{ provider, model, reasoningEffort? }` selection for a newly created Agent.
+- `ctx.agentDefaultModel.saveSelection(selection)` saves the complete user selection. Without a settings provider it is a no-op and the composition entry remains current.
+
+The service does not validate catalog membership. A provider route may serve an unadvertised model, and the consumer that actually opens a model request owns availability diagnostics.
+
+## Model Experience
+
+Indirectly, through the provider/model selection supplied to a front door; request assembly and adapters own the model-visible request.
+
+#### KV Cache effect
+
+Changing the default affects only Agents that subsequently resolve from it. An existing session whose request log already names a selection keeps that selection, so this service does not invalidate its established prefix.
+
+## Known Limitations and Deferred Work
+
+- The service owns one process-wide default; per-session selection remains the front door's responsibility.
+- Without a settings provider, `saveSelection()` cannot retain a selection for a later Agent.
--- a/packages/core/agent-default-model/README.zh.md
+++ b/packages/core/agent-default-model/README.zh.md
@@ -0,0 +1,25 @@
+# @deepseek-ai/dsh-agent-default-model
+
+[English](README.md) | 中文
+
+该部署默认值供入口在创建尚无会话级模型选择的 Agent 时使用。`AgentDefaultModelService` 提供 `ctx.agentDefaultModel`；`dsh run` 这类直接入口与 ApiProxy 这类由 Host 支撑的入口读取同一服务，而不是分别持有平行的提供方／模型默认值。
+
+插件配置必须提供 `{ provider, model }`。该组合配置项构成 Settings 中 `agent-default-model` 分节的基础层；挂载的设置提供方在其上叠加用户选择，更改会在下一次调用 `currentSelection()` 时可见。`reasoningEffort` 属于该 Settings 分节，但特意不属于插件配置：完整保存的选择必须能在下一个选定模型没有推理（reasoning）强度时清除旧值，而组合配置值会再次被继承。
+
+- `ctx.agentDefaultModel.currentSelection()` 返回一份独立的 `{ provider, model, reasoningEffort? }` 选择，供新创建的 Agent 使用。
+- `ctx.agentDefaultModel.saveSelection(selection)` 保存完整的用户选择。未挂载设置提供方时，此调用不执行任何操作，组合配置项仍为当前值。
+
+该服务不校验目录成员关系。提供方路由可以服务未在目录中公布的模型；实际发起模型请求的消费方负责可用性诊断。
+
+## 模型体验
+
+通过提供给入口的提供方／模型选择间接影响；模型可见请求由请求组装与适配器负责。
+
+#### KV Cache 影响
+
+更改默认值只影响之后从该默认值解析选择的 Agent。请求日志已经指明选择的现有会话仍沿用该选择，因此本服务不会使其已建立的前缀失效。
+
+## 已知限制与暂缓事项
+
+- 该服务只拥有一项进程级默认值；每个会话的选择仍由入口负责。
+- 未挂载设置提供方时，`saveSelection()` 无法保留选择供后续 Agent 使用。
--- a/packages/core/agent-default-model/package.json
+++ b/packages/core/agent-default-model/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "@deepseek-ai/dsh-agent-default-model",
+  "description": "Default model selection shared by Agent front doors",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "main": "lib/index.js",
+  "types": "lib/types/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./lib/types/index.d.ts",
+      "default": "./lib/index.js"
+    },
+    "./invariant": {
+      "types": "./lib/types/invariant.d.ts",
+      "default": "./lib/invariant.js"
+    },
+    "./src/*": "./src/*",
+    "./package.json": "./package.json"
+  },
+  "files": [
+    "lib/index.js",
+    "lib/invariant.js",
+    "lib/types/**/*.d.ts"
+  ],
+  "license": "BSD-3-Clause",
+  "dependencies": {
+    "schemastery": "^3.18.0"
+  },
+  "peerDependencies": {
+    "@deepseek-ai/dsh-agent": "^0.0.1",
+    "@deepseek-ai/dsh-invariants": "^0.0.1",
+    "@deepseek-ai/dsh-llm": "^0.0.1",
+    "@deepseek-ai/dsh-settings": "^0.0.1",
+    "cordis": "^4.0.0-rc.7"
+  },
+  "devDependencies": {
+    "@deepseek-ai/dsh-agent": "workspace:^",
+    "@deepseek-ai/dsh-invariants": "workspace:^",
+    "@deepseek-ai/dsh-llm": "workspace:^",
+    "@deepseek-ai/dsh-settings": "workspace:^",
+    "cordis": "^4.0.0-rc.7"
+  }
+}
--- a/packages/core/agent-default-model/src/index.ts
+++ b/packages/core/agent-default-model/src/index.ts
@@ -0,0 +1,107 @@
+/**
+ * Default model selection for an Agent without a session-specific selection.
+ *
+ * @module @deepseek-ai/dsh-agent-default-model
+ */
+
+import { Context, Service } from 'cordis'
+import z from 'schemastery'
+import type { ModelSelection } from '@deepseek-ai/dsh-agent'
+import { ReasoningEffortId } from '@deepseek-ai/dsh-llm'
+import { installSettingsSection, settingsNamespace } from '@deepseek-ai/dsh-settings'
+
+declare module 'cordis' {
+  interface Context {
+    /** Default model selection for Agents created without an explicit model. */
+    agentDefaultModel: AgentDefaultModelService
+  }
+}
+
+/** Settings namespace carrying the default model selection for future Agents. */
+export const AGENT_DEFAULT_MODEL_SETTINGS_NAMESPACE = settingsNamespace('agent-default-model')
+
+/** Stored and composed default model selection. */
+export interface AgentDefaultModelSettings {
+  /** Registered provider route. */
+  provider: string
+  /** Provider-owned model id. */
+  model: string
+  /** Adapter-owned reasoning effort, or provider/default behavior when absent. */
+  reasoningEffort?: string
+}
+
+/** Schema of the default Agent model settings section. */
+export const AGENT_DEFAULT_MODEL_SETTINGS_SCHEMA: z<AgentDefaultModelSettings> = z.object({
+  provider: z.string().required(),
+  model: z.string().required(),
+  reasoningEffort: z.string(),
+})
+
+/** Composition entry for the default model selection. */
+export interface Config {
+  /** Registered provider route. */
+  provider: string
+  /** Provider-owned model id. */
+  model: string
+}
+
+/** Project stored settings onto the Agent-facing selection type. */
+function selection(settings: AgentDefaultModelSettings): ModelSelection {
+  return {
+    provider: settings.provider,
+    model: settings.model,
+    ...settings.reasoningEffort === undefined
+      ? {}
+      : { reasoningEffort: ReasoningEffortId(settings.reasoningEffort) },
+  }
+}
+
+/**
+ * Owns the default model selection independently of any Host or transport.
+ * The composition entry remains usable without a settings provider; when one
+ * is mounted, its user layer is read live.
+ */
+export class AgentDefaultModelService extends Service {
+  static Config: z<Config> = z.object({
+    provider: z.string().required(),
+    model: z.string().required(),
+  })
+
+  private source: () => AgentDefaultModelSettings
+
+  constructor(ctx: Context, config: Config) {
+    super(ctx, 'agentDefaultModel')
+    const entry: AgentDefaultModelSettings = { provider: config.provider, model: config.model }
+    this.source = () => entry
+    installSettingsSection(ctx, AGENT_DEFAULT_MODEL_SETTINGS_NAMESPACE, AGENT_DEFAULT_MODEL_SETTINGS_SCHEMA, entry, {
+      setSource: (current) => { this.source = current },
+      // Every consumer reads through currentSelection(), so no registration-level fact
+      // needs rebuilding when the settings document changes.
+      onChange: () => {},
+    })
+  }
+
+  /**
+   * Read the current default model selection.
+   * @returns a detached provider, model, and optional reasoning selection.
+   */
+  currentSelection(): ModelSelection {
+    return selection(this.source())
+  }
+
+  /**
+   * Save the complete default model selection. A deployment without a settings
+   * provider keeps its composition entry.
+   * @param next - resolved selection accepted by a front door.
+   * @returns fulfillment after the optional settings write settles.
+   */
+  async saveSelection(next: ModelSelection): Promise<void> {
+    await this.ctx.get('settings')?.replace(AGENT_DEFAULT_MODEL_SETTINGS_NAMESPACE, {
+      provider: next.provider,
+      model: next.model,
+      ...next.reasoningEffort === undefined ? {} : { reasoningEffort: String(next.reasoningEffort) },
+    })
+  }
+}
+
+export default AgentDefaultModelService
--- a/packages/core/agent-default-model/src/invariant.ts
+++ b/packages/core/agent-default-model/src/invariant.ts
@@ -0,0 +1,30 @@
+/**
+ * Package-owned invariant companion for the default Agent model selection.
+ *
+ * The service owns no independent event relationship: settings registration
+ * already validates every mutable value before `currentSelection()` can observe it.
+ * The empty installer keeps that absence explicit in composed invariant sets.
+ *
+ * @module @deepseek-ai/dsh-agent-default-model/invariant
+ */
+
+import type { Context } from 'cordis'
+import type { InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-agent-default-model'
+
+/** Cordis companion plugin name. */
+export const name = 'agent-default-model-invariant'
+/** Services required before the companion can register. */
+export const inject = ['invariants']
+
+/** No runtime invariant: settings validation owns the only mutable-value relationship. */
+const install: InvariantInstaller = () => {}
+
+/**
+ * Register the intentionally empty invariant contribution.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))
--- a/packages/core/agent-default-model/tests/agent-default-model.spec.ts
+++ b/packages/core/agent-default-model/tests/agent-default-model.spec.ts
@@ -0,0 +1,98 @@
+/** Default Agent model settings layered over a real settings provider. */
+
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import AgentDefaultModelService, { AGENT_DEFAULT_MODEL_SETTINGS_NAMESPACE } from '../src/index.ts'
+import { Settings } from '@deepseek-ai/dsh-settings'
+import type { SettingsNamespace } from '@deepseek-ai/dsh-settings'
+import { ReasoningEffortId } from '@deepseek-ai/dsh-llm'
+
+/** The smallest real provider: one in-memory document, always writable. */
+class MemorySettings extends Settings {
+  doc: Record<string, unknown> = {}
+
+  get writable(): boolean {
+    return true
+  }
+
+  protected load(): Promise<Record<string, unknown>> {
+    return Promise.resolve(structuredClone(this.doc))
+  }
+
+  protected persist(ns: SettingsNamespace, section: Record<string, unknown>): Promise<void> {
+    this.doc = { ...this.doc, [ns]: structuredClone(section) }
+    return Promise.resolve()
+  }
+}
+
+async function boot(): Promise<{
+  ctx: Context
+  settingsFiber: Context['fiber']
+  defaultModel: AgentDefaultModelService
+}> {
+  const ctx = new Context()
+  const settingsFiber = ctx.plugin(MemorySettings)
+  await settingsFiber.await()
+  await ctx.plugin(AgentDefaultModelService, {
+    provider: 'deepseek-official',
+    model: 'deepseek-v4-flash',
+  })
+  return { ctx, settingsFiber, defaultModel: ctx.agentDefaultModel }
+}
+
+describe('AgentDefaultModelService', () => {
+  it('resolves the user layer over the composition entry', async () => {
+    const bench = await boot()
+    expect(bench.defaultModel.currentSelection()).toEqual({
+      provider: 'deepseek-official', model: 'deepseek-v4-flash',
+    })
+
+    await bench.defaultModel.saveSelection({
+      provider: 'acme-gateway', model: 'acme-large', reasoningEffort: ReasoningEffortId('high'),
+    })
+    expect(bench.defaultModel.currentSelection()).toEqual({
+      provider: 'acme-gateway', model: 'acme-large', reasoningEffort: 'high',
+    })
+    await bench.ctx.fiber.dispose()
+  })
+
+  it('clears a stored effort when the saved selection has none', async () => {
+    const bench = await boot()
+    await bench.defaultModel.saveSelection({
+      provider: 'acme-gateway', model: 'acme-large', reasoningEffort: ReasoningEffortId('high'),
+    })
+    await bench.defaultModel.saveSelection({ provider: 'acme-gateway', model: 'acme-plain' })
+    expect(bench.defaultModel.currentSelection()).toEqual({ provider: 'acme-gateway', model: 'acme-plain' })
+    await bench.ctx.fiber.dispose()
+  })
+
+  it('layers a hand-written partial section over the entry', async () => {
+    const bench = await boot()
+    await bench.settingsFiber.ctx.settings.replace(AGENT_DEFAULT_MODEL_SETTINGS_NAMESPACE, {
+      model: 'deepseek-reasoner',
+    })
+    expect(bench.defaultModel.currentSelection()).toEqual({
+      provider: 'deepseek-official', model: 'deepseek-reasoner',
+    })
+    await bench.ctx.fiber.dispose()
+  })
+
+  it('falls back to the composition entry when the settings provider detaches', async () => {
+    const bench = await boot()
+    await bench.defaultModel.saveSelection({ provider: 'acme-gateway', model: 'acme-large' })
+    expect(bench.defaultModel.currentSelection().provider).toBe('acme-gateway')
+    await bench.settingsFiber.dispose()
+    expect(bench.defaultModel.currentSelection()).toEqual({
+      provider: 'deepseek-official', model: 'deepseek-v4-flash',
+    })
+    await bench.ctx.fiber.dispose()
+  })
+
+  it('keeps the composition entry when no settings provider is mounted', async () => {
+    const ctx = new Context()
+    await ctx.plugin(AgentDefaultModelService, { provider: 'p', model: 'm' })
+    await ctx.agentDefaultModel.saveSelection({ provider: 'other', model: 'other' })
+    expect(ctx.agentDefaultModel.currentSelection()).toEqual({ provider: 'p', model: 'm' })
+    await ctx.fiber.dispose()
+  })
+})
--- a/packages/core/agent-default-model/tsconfig.json
+++ b/packages/core/agent-default-model/tsconfig.json
@@ -0,0 +1,30 @@
+{
+  "extends": "../../../tsconfig.base.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "lib/types"
+  },
+  "include": [
+    "src"
+  ],
+  "references": [
+    {
+      "path": "../../../vendor/cordis"
+    },
+    {
+      "path": "../../../vendor/schemastery"
+    },
+    {
+      "path": "../../core/agent"
+    },
+    {
+      "path": "../../llm/llm"
+    },
+    {
+      "path": "../../settings/settings"
+    },
+    {
+      "path": "../../support/invariants"
+    }
+  ]
+}
--- a/packages/core/agent-default-model/tsdown.config.ts
+++ b/packages/core/agent-default-model/tsdown.config.ts
@@ -0,0 +1,25 @@
+import { defineConfig } from 'tsdown'
+
+/** Build the package root and invariant companion as independent bundles. */
+export default defineConfig([
+  {
+    entry: ['lib/types/index.js'],
+    outDir: 'lib',
+    format: ['esm'],
+    platform: 'node',
+    target: 'es2024',
+    fixedExtension: false,
+    dts: false,
+    clean: false,
+  },
+  {
+    entry: ['lib/types/invariant.js'],
+    outDir: 'lib',
+    format: ['esm'],
+    platform: 'node',
+    target: 'es2024',
+    fixedExtension: false,
+    dts: false,
+    clean: false,
+  },
+])
--- a/packages/core/agent/README.i18n.yaml
+++ b/packages/core/agent/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/core/agent/README.md
-README.md: 3a3bdf6a4b3bdc5bfef250495e84b7d90b003822
-README.zh.md: e421070a6eec2e6e7e1fc7b45f0a5e29040bf712
+README.md: ba0fa456593e598b6532c10ef2390bbd55f3a486
+README.zh.md: 581da5c8621e5653f57edce38ac9816da7a40d40
--- a/packages/core/agent/README.md
+++ b/packages/core/agent/README.md
@@ -12,7 +12,7 @@ Tracks live agents and carries the initiating Agent through asynchronous driver

 ### Public API

-The scoped-registration surface: `Agent.ctx` is the agent's scope context (`dsh-scope`, key = the agent) — register tools/sections/variables/listeners through it for that agent alone, all unwound on disposal. `agentEvents(ctx, agent)` is the fused dispatcher for ordinary agent-subject operations (carrier + injected subject in one move); its notification mode invokes every listener and contains both synchronous throws and returned-promise rejections. The registry lifecycle pair reuses one stable routing carrier. `assembleContextFor(agent)` builds the per-agent assembly context (`agent` + `scope` together). `installAgentLlmTarget(agentCtx, target)` snapshots a mutable provider/model/reasoning-effort selection during prompt assembly, applies the route to prompt variables, and applies the complete target to request routing for one step; an absent selected effort clears an inherited effort so the target uses adapter/provider defaults. `CreateAgentOptions.setup(agentCtx)` and `ResumeAgentOptions.setup(agentCtx)` compose a fresh or resumed agent's scoped world while both objects remain unpublished. Setup is trusted, composition-only same-process code: drive the agent only after creation resolves.
+The scoped-registration surface: `Agent.ctx` is the agent's scope context (`dsh-scope`, key = the agent) — register tools/sections/variables/listeners through it for that agent alone, all unwound on disposal. `agentEvents(ctx, agent)` is the fused dispatcher for ordinary agent-subject operations (carrier + injected subject in one move); its notification mode invokes every listener and contains both synchronous throws and returned-promise rejections. The registry lifecycle pair reuses one stable routing carrier. `assembleContextFor(agent)` builds the per-agent assembly context (`agent` + `scope` together). `installModelSelection(agentCtx, selection)` snapshots a mutable provider/model/reasoning-effort selection during prompt assembly, applies its provider and model to prompt variables, and applies the complete selection to request routing for one step; an absent selected effort clears an inherited effort so adapter/provider defaults apply. `CreateAgentOptions.setup(agentCtx)` and `ResumeAgentOptions.setup(agentCtx)` compose a fresh or resumed agent's scoped world while both objects remain unpublished. Setup is trusted, composition-only same-process code: drive the agent only after creation resolves.

 `AgentOptions` supplies the initial provider/model route and an optional positive `maxTokens` output cap. The concrete loop resolves any exact-model adapter default, records the effective cap in the request header, and applies it to each conversation-model request; an explicit Agent option wins, while omission leaves the adapter or provider route default in control.

--- a/packages/core/agent/README.zh.md
+++ b/packages/core/agent/README.zh.md
@@ -12,7 +12,7 @@ Agent 接口、注册表、进程本地发起方作用域，以及 `agent/*` 事

 ### 公开 API

-带作用域的注册接口：`Agent.ctx` 是 agent 的作用域上下文（`dsh-scope`，键 = 该 agent）。通过它注册工具／段／变量／监听器，只对该 agent 生效，并在 dispose（资源释放）时全部撤销。`agentEvents(ctx, agent)` 是普通 agent 主体操作的融合分发器（一次完成载体 + 注入主体）；其通知 mode 会调用每个监听器，并同时收容同步抛出和返回 Promise 的拒绝。注册表生命周期对复用一个稳定路由载体。`assembleContextFor(agent)` 构建按 agent 的组装上下文（同时包含 `agent` + `scope`）。`installAgentLlmTarget(agentCtx, target)` 在提示词组装期间快照可变的提供方／模型／推理（reasoning）强度选择，将路由应用到提示词变量，并将完整目标应用到一个步骤的请求路由；如果没有选定推理强度，则会清除继承的推理强度，使该目标使用适配器／提供方默认值。`CreateAgentOptions.setup(agentCtx)` 和 `ResumeAgentOptions.setup(agentCtx)` 在新建或恢复的 agent 尚未发布时，组合其带作用域的世界。Setup 是受信任、仅用于组合的同进程代码：只有创建完成后才能驱动 agent。
+带作用域的注册接口：`Agent.ctx` 是 agent 的作用域上下文（`dsh-scope`，键 = 该 agent）。通过它注册工具／段／变量／监听器，只对该 agent 生效，并在 dispose（资源释放）时全部撤销。`agentEvents(ctx, agent)` 是普通 agent 主体操作的融合分发器（一次完成载体 + 注入主体）；其通知 mode 会调用每个监听器，并同时收容同步抛出和返回 Promise 的拒绝。注册表生命周期对复用一个稳定路由载体。`assembleContextFor(agent)` 构建按 agent 的组装上下文（同时包含 `agent` + `scope`）。`installModelSelection(agentCtx, selection)` 在提示词组装期间快照可变的提供方／模型／推理（reasoning）强度选择，将其中的提供方和模型应用到提示词变量，并将完整选择应用到一个步骤的请求路由；如果没有选定推理强度，则会清除继承的推理强度，使适配器／提供方默认值生效。`CreateAgentOptions.setup(agentCtx)` 和 `ResumeAgentOptions.setup(agentCtx)` 在新建或恢复的 agent 尚未发布时，组合其带作用域的世界。Setup 是受信任、仅用于组合的同进程代码：只有创建完成后才能驱动 agent。

 `AgentOptions` 提供初始的提供方／模型路由，以及可选的正数 `maxTokens` 输出上限。具体循环会解析确切模型的适配器默认值，把生效上限记录到请求 header，并应用到每次对话模型请求；显式 Agent 选项优先，省略时由适配器或提供方路由默认值控制。

--- a/packages/core/agent/src/index.ts
+++ b/packages/core/agent/src/index.ts
@@ -17,7 +17,7 @@ import type { Agent, AgentOptions } from './types.ts'

 export * from './types.ts'
 export * from './inbox.ts'
-export * from './llm-target.ts'
+export * from './model-selection.ts'
 export { agentCarrier, agentEvents, assembleContextFor, emitAgentEvent } from './dispatch.ts'
 export type { AgentEventDispatch, AgentSubjectEvent } from './dispatch.ts'

--- a/packages/core/agent/src/model-selection.ts
+++ b/packages/core/agent/src/model-selection.ts
@@ -1,13 +1,13 @@
 /**
- * Agent-scoped LLM target snapshot shared by interactive front doors.
- * @module @deepseek-ai/dsh-agent/llm-target
+ * Agent-scoped model selection shared by interactive front doors.
+ * @module @deepseek-ai/dsh-agent/model-selection
 */

 import type { Context } from 'cordis'
 import type { LlmCallConfig, ReasoningEffortId } from '@deepseek-ai/dsh-llm'

-/** Complete provider/model route and optional reasoning effort selected for one live agent. */
-export interface AgentLlmTarget {
+/** Complete provider, model, and optional reasoning effort selected for one live Agent. */
+export interface ModelSelection {
  /** Registered provider route. */
  provider: string
  /** Provider-owned model id. */
@@ -16,31 +16,31 @@ export interface AgentLlmTarget {
  reasoningEffort?: ReasoningEffortId
 }

-/** Mutable selection plus the target captured for the current step. */
-export interface AgentLlmTargetRef {
-  /** Target selected for the next step that enters prompt assembly. */
-  current: AgentLlmTarget | undefined
-  /** Target captured when the current step entered prompt assembly. */
-  assembled: AgentLlmTarget | undefined
+/** Mutable model selection plus the value captured for the current step. */
+export interface ModelSelectionRef {
+  /** Model selected for the next step that enters prompt assembly. */
+  current: ModelSelection | undefined
+  /** Selection captured when the current step entered prompt assembly. */
+  assembled: ModelSelection | undefined
 }

 /**
- * Couple one mutable target to agent-scoped prompt assembly and request routing.
- * Prompt assembly snapshots the selected target before delegating, then applies
- * its route to prompt variables and its route/effort to request config so a
+ * Couple one mutable selection to Agent-scoped prompt assembly and request routing.
+ * Prompt assembly snapshots the selected model before delegating, then applies
+ * its provider/model pair and effort to request config so a
 * concurrent switch takes effect on a later step instead of splitting the two
- * surfaces. An absent selected effort clears any inherited effort so a model
- * switch can restore that target's provider/default behavior.
+ * surfaces. An absent selected effort clears any inherited effort, restoring
+ * the selected model's provider/default behavior.
 *
- * @param agentCtx - The target agent's scoped context.
- * @param target - Mutable selection owned by the calling front door.
+ * @param agentCtx - The selected Agent's scoped context.
+ * @param selection - Mutable selection owned by the calling front door.
 * @returns Disposer for both scoped waterfall listeners.
 */
-export function installAgentLlmTarget(agentCtx: Context, target: AgentLlmTargetRef): () => void {
+export function installModelSelection(agentCtx: Context, selection: ModelSelectionRef): () => void {
  const disposeAssembly = agentCtx.on('system-prompt/assemble', async (_assembly, _context, next) => {
-    const selected = target.current
+    const selected = selection.current
    const assembled = await next()
-    target.assembled = selected
+    selection.assembled = selected
    if (selected === undefined) return assembled
    return {
      ...assembled,
@@ -55,7 +55,7 @@ export function installAgentLlmTarget(agentCtx: Context, target: AgentLlmTargetR
    'agent/request',
    async (_payload, next): Promise<LlmCallConfig> => {
      const resolved = await next()
-      const selected = target.assembled
+      const selected = selection.assembled
      if (selected === undefined) return resolved
      const { reasoningEffort: _inheritedEffort, ...withoutInheritedEffort } = resolved
      return {
--- a/packages/core/agent/tests/model-selection.spec.ts
+++ b/packages/core/agent/tests/model-selection.spec.ts
@@ -3,18 +3,18 @@ import { Context } from 'cordis'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import {
  agentEvents,
-  installAgentLlmTarget,
+  installModelSelection,
  type Agent,
-  type AgentLlmTargetRef,
+  type ModelSelectionRef,
 } from '../src/index.ts'
 import { ReasoningEffortId, type LlmCallConfig } from '@deepseek-ai/dsh-llm'

-describe('installAgentLlmTarget()', () => {
+describe('installModelSelection()', () => {
  it('snapshots prompt variables and request routing together, then disposes both listeners', async () => {
    const ctx = new Context()
    await ctx.plugin(SystemPrompt)
-    const target: AgentLlmTargetRef = { current: undefined, assembled: undefined }
-    const dispose = installAgentLlmTarget(ctx, target)
+    const selection: ModelSelectionRef = { current: undefined, assembled: undefined }
+    const dispose = installModelSelection(ctx, selection)
    const agent = {} as Agent
    const seed: LlmCallConfig = { provider: 'seed', model: 'seed', temperature: 0.2 }
    const signal = new AbortController().signal
@@ -24,13 +24,13 @@ describe('installAgentLlmTarget()', () => {
      'agent/request', { turn: 1, step: 0, signal }, () => Promise.resolve(seed),
    )).resolves.toBe(seed)

-    target.current = {
+    selection.current = {
      provider: 'alpha',
      model: 'a1',
      reasoningEffort: ReasoningEffortId('high'),
    }
    expect((await ctx.systemPrompt.assemble()).variables).toMatchObject({ provider: 'alpha', model: 'a1' })
-    target.current = { provider: 'beta', model: 'b1' }
+    selection.current = { provider: 'beta', model: 'b1' }
    await expect(agentEvents(ctx, agent).waterfall(
      'agent/request', { turn: 1, step: 0, signal }, () => Promise.resolve(seed),
    )).resolves.toEqual({
--- a/packages/host/apiproxy/README.i18n.yaml
+++ b/packages/host/apiproxy/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/host/apiproxy/README.md
-README.md: a3c9f214690144ec0f39a8690e4fd346f5e315e2
-README.zh.md: 65475351e279f258f4417f2082673382e76a5be3
+README.md: 5e3a6cf57ce3fe11b3f31d7f68055f34708d74eb
+README.zh.md: b96487d6d67deb8a0a6ddf4a92784f31dafb3e89
--- a/packages/host/apiproxy/README.md
+++ b/packages/host/apiproxy/README.md
@@ -2,19 +2,19 @@

 English | [中文](README.zh.md)

-The API gateway every client shape shares: the TS contract (`src/api/`, zero Node dependencies, importable from the browser), the fetch carrier pair (`src/fetch/`: `toFetchHandler` on the host side, `AbstractApiClient` plus platform subclasses on the client side), and the host-side implementation (`src/api-proxy.ts`: `createApiProxy` plus the default-exported `ApiProxyService` gateway plugin — config `{provider, model, reasoningEffort?, workspaceRoot?}`, provides `ctx.apiProxy`). Transport-agnostic by design: this package registers no routes; carriers such as HTTP wrap `ctx.apiProxy` themselves. The shipped core composition lives in [`packages/bundle/base/cordis.patch.yml`](../../bundle/base/cordis.patch.yml).
+The API gateway every client shape shares: the TS contract (`src/api/`, zero Node dependencies, importable from the browser), the fetch carrier pair (`src/fetch/`: `toFetchHandler` on the host side, `AbstractApiClient` plus platform subclasses on the client side), and the host-side implementation (`src/api-proxy.ts`: `createApiProxy` plus the default-exported `ApiProxyService` gateway plugin — config `{workspaceRoot?}`, provides `ctx.apiProxy`). Transport-agnostic by design: this package registers no routes; carriers such as HTTP wrap `ctx.apiProxy` themselves. The shipped Web composition lives in [`packages/bundle/web-app/cordis.patch.yml`](../../bundle/web-app/cordis.patch.yml), while its default Agent model selection belongs to [`@deepseek-ai/dsh-agent-default-model`](../../core/agent-default-model/README.md) in the base bundle.

-## The default route (`api-gateway` settings section)
+## The shared Agent default (`agent-default-model` Settings section)

-`{provider, model, reasoningEffort?}` is also the gateway's user-settings section, registered under `api-gateway`: the composition entry is the `base` layer and `settings.yaml` layers the user's own choice over it. `workspaceRoot` is deliberately outside the section — a launcher fact, not a preference.
+`ApiProxyService` consumes `ctx.agentDefaultModel`; it does not own a provider/model config or settings section. The shared service registers `{provider, model, reasoningEffort?}` under `agent-default-model`: the base bundle's composition entry is the lower layer and `settings.yaml` layers the user's choice over it. `workspaceRoot` remains ApiProxy config because it is a Host launcher fact, not a model preference.

-A session resolves its route from three tiers, re-read on every access rather than seeded once: a selection made in this process, else the session's own latest logged `request/header`, else this default. Re-reading is what makes both directions hold — a session that has run a turn derives its route from its log forever after, so changing the default never retargets it, while a session still blank (New Session reuses one rather than minting another) starts from a default saved after it was created.
+A session resolves its model selection from three tiers on every access: a selection made in this process, otherwise the session's latest logged `request/header`, otherwise this default. A session that has run a turn derives its selection from its log, while a blank session observes a default saved after it was created.

-`session.selectModel` records an accepted switch as the new default, which is how the default is chosen in practice: there is no separate gesture. What it stores is the RESOLVED target, so an adapter-materialized default effort is pinned as the user saw it and a later adapter-default change does not silently move stored defaults. The write replaces the section wholesale rather than merging, because switching to a model with no reasoning effort has to clear a stored one; a storage failure is logged without undoing the switch, which already applies to its own session. A deployment with no settings provider keeps the composition entry and a switch stays process-local.
+`session.selectModel` saves an accepted switch as the deployment default; there is no separate gesture. It stores the resolved `ModelSelection`, including an adapter-materialized default effort. The complete-section write clears a stored effort when the selected model has none. A storage failure is logged without undoing the session selection. A deployment with no settings provider keeps the composition entry and the switch remains session-local.

-The section's `reasoningEffort` has no counterpart in the plugin config, deliberately: the seam merges the user layer over the composition entry per field, so an absent key cannot override a present one and a composition-set effort would survive every later switch to a model without one. A deployment default for effort belongs on the adapter profile, which resolves per model.
+The section's `reasoningEffort` has no counterpart in the agent-default-model plugin config, deliberately: the seam merges the user layer over the composition entry per field, so an absent key cannot override a present one and a composition-set effort would survive every later switch to a model without one. A deployment default for effort belongs on the adapter profile, which resolves per model.

-The stored route is not validated against the registry, in either direction. A default naming a route the Models page has since removed still reaches `session.models` as the session's `current` — matching no advertised group, which is precisely what makes a selector prompt for a replacement instead of naming a model the deployment cannot reach. Repairing it silently would also break the deliberate converse: an adapter may serve a model its catalog does not advertise.
+The stored selection is independent of catalog membership. A default naming an unavailable provider still reaches `session.models` as the session's `current`, allowing the selector to request a replacement instead of silently choosing another model. Conversely, an adapter may serve a model that its catalog does not advertise.

 ## Contract layer (`/api`)

@@ -30,9 +30,9 @@ Question responses are validated against their pending request before the first

 Session titles ride the generic projection pair like every other domain — the history-tail `projections` block plus `session/projection` frames under the `title` key (the bespoke `session/title` frame is retired). Titles do not join `session.list`; cold sessions remain metadata-only there until opening or resuming attaches their logs. `session.rename` accepts an explicit user title (resuming a cold session first), delegating to `ctx.sessionTitle.rename` — the accepted `session/title` event pins the title against automatic regeneration — and returns the normalized title plus its event seq so a client settles its `title` projection cell ahead of the push frame; a title that normalizes to empty returns `title-invalid`.

-`session.fork` maps an optional event anchor to the first `turn/end` at or after it, letting a message action include that message's whole turn. An omitted or past-end anchor selects the last completed turn; an in-log anchor whose turn remains open returns `fork-unavailable` rather than clipping backward. The published child inherits the source's seeded history, cwd, latest logged provider/model/reasoning target, and lineage before joining the source Workspace. If Workspace attachment fails, `workspace-attach-failed` carries the already-published child id so clients can reconcile it. The [SessionStore fork decision](../../../.agents/notes/implemented/feature/2026-06-30-session-store-fork-api.md) owns the boundary rationale.
+`session.fork` maps an optional event anchor to the first `turn/end` at or after it, letting a message action include that message's whole turn. An omitted or past-end anchor selects the last completed turn; an in-log anchor whose turn remains open returns `fork-unavailable` rather than clipping backward. The published child inherits the source's seeded history, cwd, latest logged `ModelSelection`, and lineage before joining the source Workspace. If Workspace attachment fails, `workspace-attach-failed` carries the already-published child id so clients can reconcile it. The [SessionStore fork decision](../../../.agents/notes/implemented/feature/2026-06-30-session-store-fork-api.md) owns the boundary rationale.

-Session model routing is a session-domain contract. `session.models` returns the selected provider/model/reasoning target separately from provider-grouped advisory models, exact-route reasoning metadata, and provider-local lookup failures. The current target may be absent from the groups and is never injected as a synthetic row; clients can prompt for a replacement without turning the directory into a routing whitelist. `session.selectModel` validates the optional adapter-owned reasoning effort and replaces the complete target selected for the next prompt-assembly boundary. Catalog membership is not validation: an adapter may resolve an unlisted model, while an unavailable route or unsupported effort returns `model-unavailable`. `session.models` additionally reports `routable`: whether an adapter currently serves the current target's route, which is deliberately NOT derivable from the groups — a route serving a model it stopped advertising is absent from them yet perfectly usable, while a route whose adapter is gone can serve nothing. `session.prompt` refuses on that same fact with `model-unavailable` rather than spending the pre-step path to fail inside an adapter; a client that disables its composer is an affordance, and this method stays callable regardless.
+Session model selection is a session-domain contract. `session.models` returns the current `ModelSelection` separately from provider-grouped advisory models, exact-model reasoning metadata, and provider-local lookup failures. The selection may be absent from the groups and is never injected as a synthetic row; clients can prompt for another selection without turning the directory into a routing whitelist. `session.selectModel` validates the optional adapter-owned reasoning effort and assigns the complete selection for the next prompt-assembly boundary. Catalog membership is not validation: an adapter may resolve an unlisted model, while an unavailable provider or unsupported effort returns `model-unavailable`. `session.models` additionally reports `routable`: whether an adapter currently serves the selected provider. This is deliberately not derivable from the groups because an adapter may serve an unadvertised model. `session.prompt` refuses on the same fact with `model-unavailable` before opening a turn; a disabled composer is a client affordance, and the method remains callable.

 Pending queued input is a live control-plane contract, not conversation history. The gateway derives the complete `next-turn` queue from durable `agent/inbox/spliced` mutations and broadcasts authoritative `session/queue` snapshots after each change and on reconnect; pending `next-step` steering stays outside this Web projection. Within `next-step`, user-origin messages carry the `steering` placement while injected context (approval notices, task completion, attached snapshots) carries `context` and is not surfaced until claimed. The message-local `agent/inbox/inserted`, `claimed`, and `discarded` notifications remain available to lifecycle observers but do not build the queue view. `session.updateQueue` addresses one `MessageId`; edit and remove mutate the attached Agent through `Inbox.splice()`. A claim's pure deletion splice wins races before pre-step admission, so a later operation returns `queue-item-not-found`. `session.cancel` aborts only the active turn and preserves pending inbox work; after cancellation reaches quiescence and the closing turn flushes, AgentLoop claims the next waking message in FIFO order, and the browser never resends or promotes it. Queue operations never resume a cold session, and the client never infers retirement from turn or status events.

@@ -52,7 +52,7 @@ The `settings.*`, `credentials.*`, and `llm.*` domains are the configuration-pag

 ## Carrier layer (`/client` + root)

-`AbstractApiClient` holds every protocol invariant — rpcId minting, envelope wrap/unwrap, zod parsing, SSE frame decoding, unary timeout, microtask-batched envelope observation (`subscribeEnvelopes`) — while platform subclasses supply only the `doFetch` transport aspect. `InProcessApiClient` over `toFetchHandler(api)` is the isomorphic point: the full wire serialization/validation path with no network, used by `dsh run` headless.
+`AbstractApiClient` holds every protocol invariant — rpcId minting, envelope wrap/unwrap, zod parsing, SSE frame decoding, unary timeout, microtask-batched envelope observation (`subscribeEnvelopes`) — while platform subclasses supply only the `doFetch` transport aspect. `InProcessApiClient` over `toFetchHandler(api)` remains the isomorphic point for callers and carrier tests that need the full wire serialization/validation path without a network. Product `dsh run` is a direct core front door and does not mount this package.

 ## Model Experience

--- a/packages/host/apiproxy/README.zh.md
+++ b/packages/host/apiproxy/README.zh.md
@@ -2,19 +2,19 @@

 [English](README.md) | 中文

-所有客户端形态共用的 API 网关：TS 约定（`src/api/`，不依赖 Node，可从浏览器导入）、fetch 载体对（`src/fetch/`：宿主侧的 `toFetchHandler`，以及客户端侧的 `AbstractApiClient` 与平台子类）和宿主侧实现（`src/api-proxy.ts`：`createApiProxy` 加上默认导出的 `ApiProxyService` 网关插件，其配置为 `{provider, model, reasoningEffort?, workspaceRoot?}`，提供 `ctx.apiProxy`）。该包在设计上与传输方式无关，不注册任何路由；HTTP 等载体自行包装 `ctx.apiProxy`。已发布的核心组合位于 [`packages/bundle/base/cordis.patch.yml`](../../bundle/base/cordis.patch.yml)。
+所有客户端形态共用的 API 网关：TS 约定（`src/api/`，不依赖 Node，可从浏览器导入）、fetch 载体对（`src/fetch/`：宿主侧的 `toFetchHandler`，以及客户端侧的 `AbstractApiClient` 与平台子类）和宿主侧实现（`src/api-proxy.ts`：`createApiProxy` 加上默认导出的 `ApiProxyService` 网关插件，其配置为 `{workspaceRoot?}`，提供 `ctx.apiProxy`）。该包在设计上与传输方式无关，不注册任何路由；HTTP 等载体自行包装 `ctx.apiProxy`。随发行版交付的 Web 组合位于 [`packages/bundle/web-app/cordis.patch.yml`](../../bundle/web-app/cordis.patch.yml)，其默认 Agent（智能体）模型选择属于 base 组合包中的 [`@deepseek-ai/dsh-agent-default-model`](../../core/agent-default-model/README.md)。

-## 默认路由（`api-gateway` 设置段）
+## 共享 Agent 默认值（`agent-default-model` Settings 分节）

-`{provider, model, reasoningEffort?}` 同时是网关的用户设置段，注册在 `api-gateway` 之下：组合条目是 `base` 层，`settings.yaml` 把用户自己的选择叠加其上。`workspaceRoot` 刻意不在段内——它是启动器事实，不是偏好。
+`ApiProxyService` 消费 `ctx.agentDefaultModel`；它不持有提供方／模型配置或 Settings 分节。共享服务在 `agent-default-model` 下注册 `{provider, model, reasoningEffort?}`：base 组合包的组合条目是底层，`settings.yaml` 把用户选择叠加其上。`workspaceRoot` 仍属于 ApiProxy 配置，因为它是 Host 启动器事实，而不是模型偏好。

-会话按三级解析自己的路由，且每次读取都重新解析，而不是只在创建时种一次：本进程内的显式选择，其次是该会话自己最新记录的 `request/header`，最后才是这个默认值。重新解析正是让两个方向都成立的原因——已经跑过一轮的会话此后永远从自己的日志推导路由，改默认值不会重定向它；而仍然空白的会话（新建会话会复用一个，而不是再开一个）则会用上它创建之后才保存的默认值。
+会话每次访问时都按三级解析模型选择：本进程内作出的选择，其次是该会话日志中最新的 `request/header`，最后是这个默认值。已经跑过一轮的会话从自己的日志推导选择，空白会话则能观察到创建之后保存的默认值。

-`session.selectModel` 会把被接受的切换记录为新的默认值，实践中默认值就是这样选定的，没有另一个单独的手势。它存下来的是**解析后**的目标，因此适配器实体化出来的默认推理等级会按用户当时看到的样子钉住，日后适配器改了自己的默认值也不会悄悄移动已存的默认路由。写入是整段替换而非合并，因为切到一个不带推理等级的模型必须清掉已存的等级；存储失败只记日志，不会撤销这次切换——它对自己所在的会话已经生效。没有设置提供方的部署保留组合条目，切换只停留在进程内。
+`session.selectModel` 会把接受的切换保存为部署默认值；没有单独的选择动作。它存储已解析的 `ModelSelection`，包括适配器实体化的默认推理强度。完整分节写入会在所选模型没有推理强度时清除已存值。存储失败只记日志，不会撤销会话选择。没有设置提供方的部署保留组合条目，切换只对当前会话生效。

-设置段里的 `reasoningEffort` 在插件配置中刻意没有对应字段：seam 是按字段把用户层合并到组合条目之上的，缺席的键覆盖不了存在的键，因此组合层设的推理等级会在此后每一次切到不带推理等级的模型时继续存活。推理等级的部署级默认值属于适配器 profile，那里是按模型解析的。
+Settings 分节中的 `reasoningEffort` 在 agent-default-model 插件配置中刻意没有对应字段：seam 按字段把用户层合并到组合条目之上，因此缺席的键无法覆盖已有键，组合层中的推理强度会在以后选择没有推理强度的模型时继续存在。推理强度的部署默认值属于按模型解析的适配器 profile。

-存下来的路由不做注册表校验，两个方向都不做。默认值指向一个已在模型页删除的路由时，它照样作为会话的 `current` 送到 `session.models`——匹配不到任何已公布的分组，而这恰恰是让选择器提示重新选择、而不是显示一个部署根本够不着的模型的原因。静默修复它还会破坏刻意保留的反面情形：适配器可以服务一个自己目录未公布的模型。
+存储的选择独立于目录成员关系。默认值指向不可用的提供方时，它仍会作为会话的 `current` 送到 `session.models`，让选择器请求用户重新选择，而不是静默选用其他模型。反过来，适配器也可以服务其目录中未公布的模型。

 ## 约定层（`/api`）

@@ -24,15 +24,15 @@

 首个回答认领待处理请求之前，系统会对照该请求校验问题响应。多选题的回答项可以同时携带 `selected` 中的请求选项标签与非空 `custom` 文本；单选题的回答项必须二选一。标签重复、标签未知、id 不匹配、批次不完整以及自定义文本为空都会以 `bad-response` 拒绝。

-`session.history` 会读取已附加 Session 的内存状态，或通过持久化检查冷日志，而不会恢复或发布 agent（智能体），然后按追加来源的消息边界分页：`maxMessages` 统计以追加方式进入 surface 的 `user/message` 和 `assistant/message` 事件，因此仅供模型使用的替换副本不占用配额。每一页仍是一段连续的原始事件区间，从而让压缩（compaction）的仅日志溯源信息与引用它的替换留在同一页。
+`session.history` 会读取已附加 Session 的内存状态，或通过持久化检查冷日志，而不会恢复或发布 agent，然后按追加来源的消息边界分页：`maxMessages` 统计以追加方式进入 surface 的 `user/message` 和 `assistant/message` 事件，因此仅供模型使用的替换副本不占用配额。每一页仍是一段连续的原始事件区间，从而让压缩（compaction）的仅日志溯源信息与引用它的替换留在同一页。

 `session.history` 的尾页（不带 `beforeSeq`）额外携带一个可选的 `projections` 块——`ctx.sessionProjections`（`@deepseek-ai/dsh-session-projection`）上每个已注册单元的水位线快照，`asOfSeq` = 这些值共同反映到的最后一个事件 seq（空日志为 `-1`）。网关还订阅注册表的变更流，为每个状态发生变化的单元生成一个 `session/projection` mux 帧（`{sessionId, key, value, seq}`——实时推送状态，绝不入日志；客户端按 seq 高者胜维护一个按会话的通用值仓）。载体不持有任何领域知识（每个值在注册表内部已过其单元自己的 schema；协议 schema 对 `values`/`value` 保持宽松）；loadOlder 页永不携带该块，未装注册表的组合则两个面都不提供。

 会话标题与其他所有领域一样搭乘这对通用投影机制——历史尾页的 `projections` 块外加 `title` 键下的 `session/projection` 帧（专设的 `session/title` 帧已下线）。标题不会加入 `session.list`；冷会话在其中仍只有元数据，直到打开或恢复操作附加其日志。`session.rename` 接受用户显式标题（冷会话先恢复），委托给 `ctx.sessionTitle.rename`——被接受的 `session/title` 事件将标题钉住、不再被自动生成覆盖——并返回规范化后的标题及其事件 seq，让 client 在推送帧到达前就结算自己的 `title` 投影格；规范化后为空的标题返回 `title-invalid`。

-`session.fork` 将可选事件锚点映射到该锚点处或其后的首个 `turn/end`，使消息操作可包含该消息所在的完整轮次。锚点省略或超过末尾时，选择最后一个已完成轮次；若锚点已在日志中，而其所在轮次仍开放，则返回 `fork-unavailable`，不会向较早位置裁剪。发布后的子会话会先继承源会话的种子历史、cwd、日志中最新的提供方／模型／推理（reasoning）目标及谱系，再加入源 Workspace。如果附加到 Workspace 失败，`workspace-attach-failed` 会携带已发布的子会话 id，供客户端对账。[SessionStore fork 决策](../../../.agents/notes/implemented/feature/2026-06-30-session-store-fork-api.md)给出边界设计的理由。
+`session.fork` 将可选事件锚点映射到该锚点处或其后的首个 `turn/end`，使消息操作可包含该消息所在的完整轮次。锚点省略或超过末尾时，选择最后一个已完成轮次；若锚点已在日志中，而其所在轮次仍开放，则返回 `fork-unavailable`，不会向较早位置裁剪。发布后的子会话会先继承源会话的种子历史、cwd、日志中最新的 `ModelSelection` 及谱系，再加入源 Workspace。如果附加到 Workspace 失败，`workspace-attach-failed` 会携带已发布的子会话 id，供客户端对账。[SessionStore fork 决策](../../../.agents/notes/implemented/feature/2026-06-30-session-store-fork-api.md)给出边界设计的理由。

-会话模型路由属于会话领域约定。`session.models` 将选中的提供方／模型／推理目标，与按提供方分组的建议性模型、精确路由推理元数据和逐提供方查询失败记录分开返回。当前目标可能不在这些分组中，也绝不会作为合成行注入；客户端可以提示用户选择替代目标，而无需把目录变成路由白名单。`session.selectModel` 校验由适配器持有的可选推理强度，并替换将在下一提示词组装边界使用的完整目标。目录成员关系不构成校验：适配器可以解析未列出的模型，而不可用路由或不受支持的推理强度会返回 `model-unavailable`。`session.models` 还会报告 `routable`：当前目标的路由是否有适配器在服务。这一点刻意不由分组推导——一条仍在服务、只是不再公布该模型的路由不在分组里，却完全可用；而适配器已经消失的路由什么都服务不了。`session.prompt` 依据同一个事实以 `model-unavailable` 拒绝，而不是把整条 pre-step 路径走完再在适配器内部失败；客户端禁用输入框只是提示性设计，这个方法始终可被调用。
+会话模型选择属于会话领域约定。`session.models` 将当前 `ModelSelection` 与按提供方分组的建议性模型、精确模型的推理（reasoning）元数据和逐提供方查询失败记录分开返回。该选择可能不在这些分组中，也绝不会作为合成行注入；客户端可以提示用户作出另一项选择，而无需把目录变成路由白名单。`session.selectModel` 校验由适配器持有的可选推理强度，并指定将在下一提示词组装边界使用的完整选择。目录成员关系不构成校验：适配器可以解析未列出的模型，而不可用的提供方或不受支持的推理强度会返回 `model-unavailable`。`session.models` 还会报告 `routable`，即当前是否有适配器为所选提供方提供服务。该值刻意不从分组推导，因为适配器可以服务未公布的模型。`session.prompt` 会依据同一事实，在开启轮次之前以 `model-unavailable` 拒绝；客户端禁用 composer 只是提示性设计，这个方法始终可被调用。

 待处理的 queued 输入属于实时控制平面约定，而非对话历史。网关根据持久 `agent/inbox/spliced` 变更派生完整的 `next-turn` 队列，并在每次变更后及重连时广播权威 `session/queue` 快照；待处理的 `next-step` steering（中途引导）不进入此 Web 投影。在 `next-step` 内，用户来源的消息携带 `steering` placement，而注入上下文（审批通知、任务完成、附加快照）携带 `context`，领取前不对外呈现。面向单条消息的 `agent/inbox/inserted`、`claimed` 与 `discarded` 通知仍供生命周期观察方使用，但不用于构建队列视图。`session.updateQueue` 通过 `MessageId` 寻址单个项；编辑和移除经已挂载 Agent 的 `Inbox.splice()` 修改队列。claim 的纯删除 splice 会在 pre-step 准入前赢得竞态，因此之后的操作返回 `queue-item-not-found`。`session.cancel` 仅中止活动轮次并保留待处理 inbox 工作；取消达到完全停稳且结束中的轮次完成 flush 后，AgentLoop 按 FIFO 顺序认领下一条可唤醒消息，浏览器绝不重发或提升它。队列操作绝不恢复冷会话，客户端也绝不根据轮次或状态事件推断某项已退出队列。

@@ -52,7 +52,7 @@ Workspace 列表与 Session 列表是相互独立的重连基线。`workspace.cr

 ## 载体层（`/client` + 根路径）

-`AbstractApiClient` 持有全部协议不变量：签发 rpcId、包装／解包信封、Zod 解析、SSE 帧解码、一元请求超时，以及按微任务批处理的信封观测（`subscribeEnvelopes`）；平台子类只提供 `doFetch` 传输环节。`InProcessApiClient` 以 `toFetchHandler(api)` 为基础，是同构接点：它运行完整的协议序列化与校验路径而不经过网络，供 `dsh run` headless 模式使用。
+`AbstractApiClient` 持有全部协议不变量：签发 rpcId、包装／解包信封、Zod 解析、SSE 帧解码、一元请求超时，以及按微任务批处理的信封观测（`subscribeEnvelopes`）；平台子类只提供 `doFetch` 传输环节。`InProcessApiClient` 以 `toFetchHandler(api)` 为基础，仍是同构接点：它运行完整的协议序列化与校验路径而不经过网络，供需要该路径的调用方和载体测试使用。产品的 `dsh run` 是直连 core 的入口，不挂载本包。

 ## 模型体验

--- a/packages/host/apiproxy/package.json
+++ b/packages/host/apiproxy/package.json
@@ -39,6 +39,7 @@
  "license": "BSD-3-Clause",
  "dependencies": {
    "@deepseek-ai/dsh-agent": "workspace:^",
+    "@deepseek-ai/dsh-agent-default-model": "workspace:^",
    "@deepseek-ai/dsh-api-remotes": "workspace:^",
    "@deepseek-ai/dsh-brand": "workspace:^",
    "@deepseek-ai/dsh-commands": "workspace:^",
--- a/packages/host/apiproxy/src/api-proxy.ts
+++ b/packages/host/apiproxy/src/api-proxy.ts
@@ -7,8 +7,9 @@ import { randomUUID } from 'node:crypto'
 import { mkdir, stat } from 'node:fs/promises'
 import { join } from 'node:path'
 import type { Context } from 'cordis'
-import { installAgentLlmTarget } from '@deepseek-ai/dsh-agent'
-import type { Agent, AgentLlmTarget, AgentLlmTargetRef, AgentOptions, AgentStatus } from '@deepseek-ai/dsh-agent'
+import { installModelSelection } from '@deepseek-ai/dsh-agent'
+import type { Agent, ModelSelection, ModelSelectionRef, AgentOptions, AgentStatus } from '@deepseek-ai/dsh-agent'
+import { AGENT_DEFAULT_MODEL_SETTINGS_NAMESPACE } from '@deepseek-ai/dsh-agent-default-model'
 import { createUserMessage, freezeMessage, ReasoningEffortId } from '@deepseek-ai/dsh-llm'
 import { errorChain } from '@deepseek-ai/dsh-llm'
 import type { MessageSource } from '@deepseek-ai/dsh-llm'
@@ -83,14 +84,6 @@ import { openNativePath, openNativeTextFile } from './native-path-opener.ts'
 /** Page size when history is called without maxMessages. */
 const DEFAULT_MAX_MESSAGES = 50

-/**
- * The settings namespace carrying the user's default route. Named for the
- * gateway rather than for the package, because this key is what a person reads
- * and writes in `settings.yaml`; the row id in a composition happens to match
- * but does not determine it.
- */
-export const API_GATEWAY_SETTINGS_NAMESPACE = settingsNamespace('api-gateway')
-
 /** Non-model settings namespaces intentionally served to the Web client. */
 const WEB_SETTINGS_NAMESPACES = ['permission'] as const

@@ -152,7 +145,7 @@ function ok<T>(request: RpcRequest<unknown>, value: T): RpcResponse<T> {
 /**
 * Build the provider/model catalog over every registered route. Shared by the
 * session-scoped `session.models` and host-scoped `llm.models`. Catalog
- * membership stays advisory: an unlisted session target remains valid for
+ * membership stays advisory: an unlisted session selection remains valid for
 * provider dispatch, but is not injected back into the selector after its
 * owning catalog stops advertising it. Per-provider failures ride `failures`
 * without failing the sound groups; groups that advertise nothing are dropped.
@@ -345,14 +338,14 @@ function directoryError(error: unknown): RpcError {
  return { code: 'internal', message: error instanceof Error ? error.message : String(error), details: {} }
 }

-/** Resolved Host routing and project-directory defaults consumed by the API implementation. */
+/** Resolved Agent model and project-directory defaults consumed by the API implementation. */
 export interface ApiProxyDefaults {
  /**
-   * The route a session starts from when its own log names none. Read on
+   * The model selection a session starts from when its own log names none. Read on
   * every access rather than captured, so a default saved during this process
   * reaches the sessions that have not run a turn yet.
   */
-  defaultTarget: () => AgentLlmTarget
+  defaultModelSelection: () => ModelSelection
  /**
   * Record a selection as the new default. Either absent, or a closure that
   * may itself decline — the gateway plugin always passes one, and it no-ops
@@ -361,7 +354,7 @@ export interface ApiProxyDefaults {
   * reported and swallowed: the switch already applies to its own session,
   * and undoing it because storage failed would be the worse outcome.
   */
-  persistDefaultTarget?: (target: AgentLlmTarget) => Promise<void>
+  saveDefaultModelSelection?: (selection: ModelSelection) => Promise<void>
  /** Default project directory for new sessions whose create request carries no cwd. */
  cwd: string
  /** Parent directory for name-created workspaces. */
@@ -734,17 +727,17 @@ function changedWorkspaceView(workspaceId: string, value: unknown): WorkspaceVie
 /**
 * Implement ApiProxy over a composed host context.
 * @param ctx - a context with the Host spine and Workspace registry mounted.
- * @param defaults - host routing and project-directory defaults.
+ * @param defaults - Agent model and project-directory defaults.
 * @returns the ApiProxy implementation.
 */
 export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiProxy {
-  /** The seed route each create/resume declares; re-read so it never goes stale. */
+  /** The seed model each create/resume declares; re-read so it never goes stale. */
  const agentOptions = (): AgentOptions => {
-    const { provider, model } = defaults.defaultTarget()
+    const { provider, model } = defaults.defaultModelSelection()
    return { provider, model }
  }
-  type WebLlmTargetRef = AgentLlmTargetRef & { current: AgentLlmTarget }
-  const targets = new WeakMap<Agent, WebLlmTargetRef>()
+  type WebModelSelectionRef = ModelSelectionRef & { current: ModelSelection }
+  const selections = new WeakMap<Agent, WebModelSelectionRef>()
  /** Client-chosen identity creation/resume, deduplicated across concurrent retries. */
  const sessionCreations = new Map<SessionId, Promise<Agent>>()
  /** Serializes path ownership and explicit title checks with Workspace mutations. */
@@ -754,29 +747,28 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
  const muxQueues = new Set<FrameQueue<RpcRequest<MuxFrame>>>()

  /**
-   * Install or return the session-local target that prompt assembly snapshots.
+   * Install or return the session-local model selection that prompt assembly snapshots.
   *
   * Precedence, resolved on EVERY read rather than seeded once: a selection
   * made in this process, else the session's own latest logged request/header,
-   * else the live host default. Re-reading is what keeps the two tiers honest
-   * in both directions — a session that has run a turn derives its route from
-   * its log forever after, so changing the default never retargets it; and a
-   * session still blank (New Session reuses one rather than minting another)
-   * starts from a default saved after it was created. There is no create-time
+   * else the live Agent default. Re-reading keeps the two tiers exact in both
+   * directions: a session with a recorded request derives its selection from
+   * its log, while a blank session (New Session reuses one rather than minting
+   * another) reads any default saved after it was created. There is no create-time
   * per-session override tier on this wire — if one returns (a create-options
   * contribution), it must fold in between the selection and the log.
   */
-  function targetFor(agent: Agent): WebLlmTargetRef {
-    const installed = targets.get(agent)
+  function selectionFor(agent: Agent): WebModelSelectionRef {
+    const installed = selections.get(agent)
    if (installed !== undefined) return installed
-    let picked: AgentLlmTarget | undefined
-    const target: WebLlmTargetRef = {
-      get current(): AgentLlmTarget {
+    let picked: ModelSelection | undefined
+    const selection: WebModelSelectionRef = {
+      get current(): ModelSelection {
        if (picked !== undefined) return picked
        // Incrementally folded by the session, so a per-step read costs
        // O(new events) rather than a rescan.
        const logged = agent.session.requestHeader()?.config
-        if (logged === undefined) return defaults.defaultTarget()
+        if (logged === undefined) return defaults.defaultModelSelection()
        return {
          provider: logged.provider,
          model: logged.model,
@@ -785,21 +777,21 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
            : { reasoningEffort: logged.reasoningEffort },
        }
      },
-      set current(next: AgentLlmTarget) {
+      set current(next: ModelSelection) {
        picked = next
      },
      assembled: undefined,
    }
-    installAgentLlmTarget(agent.ctx, target)
-    targets.set(agent, target)
-    return target
+    installModelSelection(agent.ctx, selection)
+    selections.set(agent, selection)
+    return selection
  }

  /** Pre-publication setup used by both fresh and resumed Web agents. */
-  function installTarget(agentCtx: Context): void {
+  function installSelection(agentCtx: Context): void {
    const agent = agentCtx.agent
    if (agent === undefined) throw new Error('api-proxy: agent setup has no scoped agent')
-    targetFor(agent)
+    selectionFor(agent)
  }

  const hasSubagentOwner = (
@@ -810,7 +802,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
    apiRemoteSubagentOwnershipError(sessionId)
  const inspectServable = (sessionId: SessionId): Promise<{ meta: SessionHeader; events: SessionEvent[] }> =>
    inspectApiRemoteSession(ctx, sessionId)
-  const agentFor = createApiRemoteAgentResolver(ctx, { agentOptions, setup: installTarget })
+  const agentFor = createApiRemoteAgentResolver(ctx, { agentOptions, setup: installSelection })

  /** Send one transient frame to every connected mux consumer. */
  function broadcast(payload: MuxFrame): void {
@@ -1076,7 +1068,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
          return (await ctx.agents.resume({
            resumeSessionId: sessionId,
            agentOptions: agentOptions(),
-            setup: installTarget,
+            setup: installSelection,
          })).agent
        }

@@ -1089,7 +1081,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
          sessionId,
          agentOptions: agentOptions(),
          meta: { cwd },
-          setup: installTarget,
+          setup: installSelection,
        })).agent
      })().catch((error: unknown) => {
        // Another Host entry path may have published the same identity while
@@ -1235,10 +1227,10 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
  }

  /**
-   * Whether an adapter currently serves this route, and therefore whether a
-   * session pointed at it can start a turn. Catalog membership cannot answer
+   * Whether an adapter currently serves this provider, and therefore whether
+   * a session selecting it can start a turn. Catalog membership cannot answer
   * it: an adapter may serve a model its own catalog stopped advertising, so
-   * a route missing from the groups is not the same as one nothing serves.
+   * a provider missing from the groups is not the same as one nothing serves.
   * A composition with no llm registry at all cannot judge and says yes —
   * the dispatch it would have refused fails on its own terms.
   */
@@ -1249,7 +1241,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro

  /**
   * Resolve the addressed agent for a turn-starting method and refuse when no
-   * adapter serves its current route: a route nothing serves cannot start a
+   * adapter serves its current selection: a provider nothing serves cannot start a
   * turn, and letting it try spends the whole pre-step path to fail inside
   * the adapter with a message about registration. Refusing here names the
   * model the session is pointed at while the draft is still in the composer.
@@ -1262,13 +1254,13 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
    const found = await agentFor(sessionId)
    if ('error' in found) return { refused: err(request, found.error) }
    const agent = found.agent
-    const target = targetFor(agent).current
-    if (!routeServed(target.provider)) {
+    const selection = selectionFor(agent).current
+    if (!routeServed(selection.provider)) {
      return {
        refused: err(request, {
          code: 'model-unavailable',
-          message: `no adapter serves provider "${target.provider}"; select a model for this session`,
-          details: { provider: target.provider, model: target.model },
+          message: `no adapter serves provider "${selection.provider}"; select a model for this session`,
+          details: { provider: selection.provider, model: selection.model },
        }),
      }
    }
@@ -1643,7 +1635,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
        const { sessionId } = request.payload
        const found = await agentFor(sessionId)
        if ('error' in found) return err(request, found.error)
-        const current = targetFor(found.agent).current
+        const current = selectionFor(found.agent).current
        const { groups, failures } = await buildModelCatalog(ctx)
        const routable = routeServed(current.provider)
        return ok(request, { current: { ...current }, routable, groups, failures })
@@ -1661,20 +1653,20 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
              ? {}
              : { reasoningEffort: ReasoningEffortId(reasoningEffort) },
          })
-          const selected: AgentLlmTarget = {
+          const selected: ModelSelection = {
            provider: resolved.provider,
            model: resolved.model,
            ...resolved.reasoningEffort === undefined
              ? {}
              : { reasoningEffort: resolved.reasoningEffort },
          }
-          targetFor(found.agent).current = selected
+          selectionFor(found.agent).current = selected
          // A switch is also how this deployment's default is chosen: the next
          // session created without one of its own starts here. Sessions that
-          // have already logged a route are unaffected — they derive from
-          // their own log (see targetFor).
+          // have already logged a selection are unaffected — they derive from
+          // their own log (see selectionFor).
          try {
-            await defaults.persistDefaultTarget?.(selected)
+            await defaults.saveDefaultModelSelection?.(selected)
          } catch (error: unknown) {
            ctx.logger.warn(
              `api-proxy: the model switch applies to this session but was not saved as the default: ${String(error)}`,
@@ -1783,7 +1775,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
              seedLength: cut,
            },
            agentOptions: agentOptions(),
-            setup: installTarget,
+            setup: installSelection,
          })
        } catch (error: unknown) {
          return err(request, {
@@ -2192,7 +2184,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
    host: {
      describe(request) {
        // TODO(step2): version should read apps/cli's package.json; placeholder for now.
-        const route = defaults.defaultTarget()
+        const selection = defaults.defaultModelSelection()
        return Promise.resolve(ok(request, {
          version: '0.0.1',
          // Same source as session.create's fallback: the UI's default project
@@ -2200,8 +2192,8 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
          cwd: defaults.cwd,
          // Read live for the same reason: this is what the NEXT session will
          // start from, so a saved default has to be what it reports.
-          provider: route.provider,
-          model: route.model,
+          provider: selection.provider,
+          model: selection.model,
          attachedSessions: ctx.agents.list().length,
        }))
      },
@@ -2730,11 +2722,11 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
            // A provider's own settings carry its model catalog and endpoint,
            // so a change there invalidates the model list even when the route
            // set is untouched — `llm/adapters-updated` alone misses it. The
-            // gateway's own section is the other such source: it names the
-            // route every session with no logged one resolves to, so an
+            // Agent default section is the other such source: it names the
+            // selection every session with no logged one resolves to, so an
            // externally edited default (another tab, a hand-edited
            // settings.yaml) has to reach an open selector too.
-            if (modelProviderNamespaces().has(name) || name === String(API_GATEWAY_SETTINGS_NAMESPACE)) {
+            if (modelProviderNamespaces().has(name) || name === String(AGENT_DEFAULT_MODEL_SETTINGS_NAMESPACE)) {
              queue.push(frame({ type: 'host/models-changed' }))
            }
          }),
--- a/packages/host/apiproxy/src/api/index.ts
+++ b/packages/host/apiproxy/src/api/index.ts
@@ -37,7 +37,7 @@ export interface ApiProxy {
 // ---- Domain interfaces and payload entities ----
 export type {
  HistoryEntry, ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
-  ModelReasoningEffort, ModelTarget, QueueAction, SessionModels, SessionProjectionsBlock, SessionSearchItem,
+  ModelReasoningEffort, ModelSelection, QueueAction, SessionModels, SessionProjectionsBlock, SessionSearchItem,
  SessionsApi, SessionSummary,
 } from './sessions.ts'
 export type { DirectoryEntry, DirectoryListing, HostApi } from './host.ts'
--- a/packages/host/apiproxy/src/api/llm.ts
+++ b/packages/host/apiproxy/src/api/llm.ts
@@ -3,8 +3,8 @@
 * surfaces. `llm.providers` merges the configurable-provider directory
 * (which providers CAN be configured, and where their settings live) with the
 * live route registry; `llm.models` is the session-independent model catalog
- * (the same groups as `session.models`, without the per-session current
- * target). Both invalidate on the `host/models-changed` frame.
+ * (the same groups as `session.models`, without a per-session selection).
+ * Both invalidate on the `host/models-changed` frame.
 */

 import type { RpcRequest, RpcResponse } from './rpc.ts'
--- a/packages/host/apiproxy/src/api/sessions.schema.ts
+++ b/packages/host/apiproxy/src/api/sessions.schema.ts
@@ -12,7 +12,7 @@ import type { RequestPayload, ResponseValue } from './rpc-map.ts'
 import type { Wire } from './rpc.schema.ts'
 import type {
  HistoryEntry, ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
-  ModelReasoningEffort, ModelTarget, SessionProjectionsBlock, SessionSearchItem, SessionSummary,
+  ModelReasoningEffort, ModelSelection, SessionProjectionsBlock, SessionSearchItem, SessionSummary,
 } from './sessions.ts'
 import type { ToolEventView } from './events.ts'
 import type { WorkspaceId } from './workspace.ts'
@@ -140,12 +140,12 @@ export const sessionHistoryRequestSchema = z.object({
  maxMessages: z.number().int().positive().optional(),
 }) satisfies z.ZodType<Wire<RequestPayload<'session.history'>>>

-/** Complete provider/model target. */
-export const modelTargetSchema = z.object({
+/** Complete provider/model selection. */
+export const modelSelectionSchema = z.object({
  provider: z.string().min(1),
  model: z.string().min(1),
  reasoningEffort: z.string().min(1).optional(),
-}) satisfies z.ZodType<Wire<ModelTarget>>
+}) satisfies z.ZodType<Wire<ModelSelection>>

 /** One adapter-owned reasoning effort. */
 export const modelReasoningEffortSchema = z.object({
@@ -224,7 +224,7 @@ export const sessionModelsRequestSchema = z.object({

 /** session.models response value. */
 export const sessionModelsValueSchema = z.object({
-  current: modelTargetSchema,
+  current: modelSelectionSchema,
  routable: z.boolean(),
  groups: z.array(modelProviderGroupSchema),
  failures: z.array(modelCatalogFailureSchema),
@@ -240,7 +240,7 @@ export const sessionSelectModelRequestSchema = z.object({

 /** session.selectModel response value. */
 export const sessionSelectModelValueSchema = z.object({
-  selected: modelTargetSchema,
+  selected: modelSelectionSchema,
 }) satisfies z.ZodType<Wire<ResponseValue<'session.selectModel'>>>

 /** ContentBlock passthrough: core is merge-extensible — the type discriminant envelope is strict, the rest stays wide. */
--- a/packages/host/apiproxy/src/api/sessions.ts
+++ b/packages/host/apiproxy/src/api/sessions.ts
@@ -53,8 +53,8 @@ export interface SessionProjectionsBlock {
  values: Partial<SessionProjectionMap>
 }

-/** Complete model target selected for one session. */
-export interface ModelTarget {
+/** Complete model selection for one session. */
+export interface ModelSelection {
  /** Registered provider route. */
  provider: string
  /** Provider-owned model id. */
@@ -115,8 +115,8 @@ export interface ModelCatalogFailure {

 /** Detached model-directory snapshot for one session. */
 export interface SessionModels {
-  /** Target selected for the session's next assembled step. */
-  current: ModelTarget
+  /** Model selection for the session's next assembled step. */
+  current: ModelSelection
  /**
   * Whether an adapter currently serves `current.provider`, and therefore
   * whether this session can start a turn at all. Deliberately NOT derivable
@@ -240,7 +240,7 @@ export interface SessionsApi {
  models(request: RpcRequest<{ sessionId: SessionId }>): Promise<RpcResponse<SessionModels>>

  /**
-   * Selects the complete target for this session. Exact model metadata
+   * Selects the complete model selection for this session. Exact model metadata
   * validates an optional reasoning effort, while catalog membership remains
   * advisory. Session-backed subagents reject with `agent-busy`.
   */
@@ -250,7 +250,7 @@ export interface SessionsApi {
    model: string
    reasoningEffort?: string
  }>):
-  Promise<RpcResponse<{ selected: ModelTarget }>>
+  Promise<RpcResponse<{ selected: ModelSelection }>>

  /**
   * Renames a session: appends a `session/title` event with the `user`
--- a/packages/host/apiproxy/src/index.ts
+++ b/packages/host/apiproxy/src/index.ts
@@ -7,28 +7,24 @@
 * `ctx.apiProxy`). Transport-agnostic by design: this package registers no
 * routes — physical carriers wrap `ctx.apiProxy` themselves.
 *
- * The gateway also owns the `api-gateway` settings section: the route a
- * session starts from when its own log names none. The composition entry is
- * the shipped default and the section layers the user's choice over it, so
- * switching models in a conversation is what sets the default for the next
- * one. Sessions that have already logged a route are never retargeted by it.
+ * The gateway consumes `ctx.agentDefaultModel`, the transport-independent default
+ * shared with direct front doors. Switching models persists through that
+ * service; sessions that have already logged a selection remain unchanged.
 */

 import { resolve } from 'node:path'
 import { Context, Service } from 'cordis'
 import z from 'schemastery'
-import type { AgentLlmTarget } from '@deepseek-ai/dsh-agent'
-import { ReasoningEffortId } from '@deepseek-ai/dsh-llm'
-import { installSettingsSection } from '@deepseek-ai/dsh-settings'
+import type {} from '@deepseek-ai/dsh-agent-default-model'
 import type { ApiProxy } from './api/index.ts'
-import { API_GATEWAY_SETTINGS_NAMESPACE, createApiProxy } from './api-proxy.ts'
+import { createApiProxy } from './api-proxy.ts'

 export type * from './api/index.ts'
 export { RpcId } from './api/rpc.ts'
 export { toFetchHandler } from './fetch/handler.ts'
 export { AbstractApiClient, InProcessApiClient } from './fetch/client.ts'
 export type { IApiClient } from './fetch/client.ts'
-export { API_GATEWAY_SETTINGS_NAMESPACE, createApiProxy } from './api-proxy.ts'
+export { createApiProxy } from './api-proxy.ts'
 export type { ApiProxyDefaults } from './api-proxy.ts'

 declare module 'cordis' {
@@ -38,62 +34,12 @@ declare module 'cordis' {
  }
 }

-/**
- * The `api-gateway` settings section: the route a session starts from when its
- * own log names none. `workspaceRoot` is deliberately not part of it — that is
- * a launcher fact, not a preference.
- */
-export interface DefaultRouteSettings {
-  /** Default provider route for created agents. */
-  provider: string
-  /** Default model id. */
-  model: string
-  /** Default reasoning effort; absence preserves the adapter/provider default. */
-  reasoningEffort?: string
-}
-
-/**
- * Gateway plugin config: host-level agent routing and Workspace creation root.
- *
- * `reasoningEffort` is deliberately absent, so the section carries one field
- * the composition cannot. The seam resolves a section by MERGING the user
- * layer over the composition entry per field, and an absent key cannot
- * override a present one — so a composition-set effort would survive every
- * later switch to a model that has none, and strand it for the next session
- * to fail on. Effort is a per-model fact anyway: a deployment default belongs
- * on the adapter profile (`llm-pi-ai`'s `reasoning`, `llm-deepseek`'s own),
- * which resolves per model rather than per gateway.
- */
+/** Gateway plugin config: the Host-only Workspace creation root. */
 export interface Config {
-  /** Default provider route for created agents. */
-  provider: string
-  /** Default model id. */
-  model: string
  /** Parent directory for name-created Workspaces; defaults to the Host cwd. */
  workspaceRoot?: string
 }

-/**
- * Schema of the `api-gateway` section, exported because it IS that section's
- * contract — the shape anything reading or writing `settings.yaml` addresses.
- */
-export const DEFAULT_ROUTE_SCHEMA: z<DefaultRouteSettings> = z.object({
-  provider: z.string().required(),
-  model: z.string().required(),
-  reasoningEffort: z.string(),
-})
-
-/** Project the stored/composed section onto the agent-facing target shape. */
-function routeTarget(settings: DefaultRouteSettings): AgentLlmTarget {
-  return {
-    provider: settings.provider,
-    model: settings.model,
-    ...settings.reasoningEffort === undefined
-      ? {}
-      : { reasoningEffort: ReasoningEffortId(settings.reasoningEffort) },
-  }
-}
-
 /**
 * The API gateway service: implements the ApiProxy contract over the composed
 * host context and provides it as `ctx.apiProxy`. The Host cwd is the default
@@ -101,13 +47,11 @@ function routeTarget(settings: DefaultRouteSettings): AgentLlmTarget {
 */
 export class ApiProxyService extends Service implements ApiProxy {
  static inject = [
-    'agents', 'directoryPicker', 'llm', 'sessions', 'subagents', 'sessionQuery',
+    'agentDefaultModel', 'agents', 'directoryPicker', 'llm', 'sessions', 'subagents', 'sessionQuery',
    'tools', 'userInteraction', 'workspace',
  ]

  static Config: z<Config> = z.object({
-    provider: z.string().required(),
-    model: z.string().required(),
    workspaceRoot: z.string(),
  })

@@ -127,30 +71,9 @@ export class ApiProxyService extends Service implements ApiProxy {
  constructor(ctx: Context, config: Config) {
    super(ctx, 'apiProxy')
    const cwd = process.cwd()
-    // The composition entry is the shipped default; the settings section
-    // layers the user's own choice over it, and a deployment without a
-    // settings provider simply keeps the entry.
-    const entry: DefaultRouteSettings = { provider: config.provider, model: config.model }
-    let route: () => DefaultRouteSettings = () => entry
-    installSettingsSection(ctx, API_GATEWAY_SETTINGS_NAMESPACE, DEFAULT_ROUTE_SCHEMA, entry, {
-      setSource: (current) => {
-        route = current
-      },
-      // Nothing registration-level derives from the default: every consumer
-      // reads it through the thunk at the moment it needs a route.
-      onChange: () => {},
-    })
    const api = createApiProxy(ctx, {
-      defaultTarget: () => routeTarget(route()),
-      // Wholesale, never a merge: switching to a model with no reasoning
-      // effort must clear a stored one, and a merged patch would strand it
-      // for the next session to fail on. This clears it because the entry
-      // below the user layer carries no effort to re-inherit — the reason
-      // `Config` deliberately has no such field. The section holds no
-      // secrets, so there is nothing a replace can collaterally drop.
-      persistDefaultTarget: async (target) => {
-        await ctx.get('settings')?.replace(API_GATEWAY_SETTINGS_NAMESPACE, target)
-      },
+      defaultModelSelection: () => ctx.agentDefaultModel.currentSelection(),
+      saveDefaultModelSelection: selection => ctx.agentDefaultModel.saveSelection(selection),
      cwd,
      workspaceRoot: resolve(config.workspaceRoot ?? cwd),
    })
--- a/packages/host/apiproxy/tests/api-proxy-approval.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-approval.spec.ts
@@ -27,7 +27,7 @@ async function harness(): Promise<{ ctx: Context; api: ApiProxy }> {
  await ctx.plugin(UserInteractionService)
  await ctx.plugin(AgentRegistry)
  await ctx.plugin(ApprovalService)
-  const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+  const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
  return { ctx, api }
 }

@@ -217,7 +217,7 @@ describe('approval pending registry', () => {
    await ctx.plugin(ApprovalService)
    let api!: ApiProxy
    const fiber = ctx.plugin(Object.assign((fiberCtx: Context) => {
-      api = createApiProxy(fiberCtx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+      api = createApiProxy(fiberCtx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
    }, { inject: ['sessions', 'agents', 'userInteraction', 'approval'] }))
    await fiber.await()
    const abort = new AbortController()
--- a/packages/host/apiproxy/tests/api-proxy-blank.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-blank.spec.ts
@@ -35,7 +35,7 @@ async function harness(): Promise<{ ctx: Context; api: ApiProxy; attach: (sessio
  await ctx.plugin(AgentRegistry)
  return {
    ctx,
-    api: createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }),
+    api: createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }),
    attach: (session) => {
      ctx.agents.register({ id: session.id, session, status: 'idle', ctx } as Agent)
    },
--- a/packages/host/apiproxy/tests/api-proxy-cold.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-cold.spec.ts
@@ -64,7 +64,7 @@ describe('sessions.list cold merge', () => {
        return undefined
      },
    })
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const response = await api.sessions.list(request({}))
    expect(response.result.ok).toBe(true)
@@ -92,7 +92,7 @@ describe('attached updatedAt excludes end-seed', () => {
    await ctx.plugin(SessionStore)
    await ctx.plugin(UserInteractionService)
    await ctx.plugin(AgentRegistry)
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    // Old work, resumed just now: the log tail would report the pickup.
    const worked = 1_000_000
@@ -150,7 +150,7 @@ describe('cold history recovery view', () => {
      inspect: (id: SessionId, signal?: AbortSignal) => coordinator.inspect(id, signal),
      locate: () => undefined,
    } as never)
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const history = await api.sessions.history(request({ sessionId, beforeSeq: 2, maxMessages: 10 }))
    if (!history.result.ok) throw new Error('history failed')
@@ -206,7 +206,7 @@ describe('Remote Agent and Session lookup policy', () => {
    })
    const defaultAgentLookup = ctx.typert.lookups.get('agent')
    const defaultSessionLookup = ctx.typert.lookups.get('session')
-    createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
    await vi.waitFor(() => {
      expect(ctx.typert.lookups.get('agent')).not.toBe(defaultAgentLookup)
      expect(ctx.typert.lookups.get('session')).not.toBe(defaultSessionLookup)
@@ -250,7 +250,7 @@ describe('Remote Agent and Session lookup policy', () => {
    const resume = vi.spyOn(ctx.agents, 'resume')
    const defaultAgentLookup = ctx.typert.lookups.get('agent')
    const defaultSessionLookup = ctx.typert.lookups.get('session')
-    createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
    await vi.waitFor(() => {
      expect(ctx.typert.lookups.get('agent')).not.toBe(defaultAgentLookup)
      expect(ctx.typert.lookups.get('session')).not.toBe(defaultSessionLookup)
@@ -312,7 +312,7 @@ describe('subagent ownership fence', () => {
      locate: () => undefined,
    } as never)
    const resume = vi.spyOn(ctx.agents, 'resume')
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const history = await api.sessions.history(request({ sessionId }))
    expect(history.result.ok).toBe(true)
@@ -371,7 +371,7 @@ describe('subagent ownership fence', () => {
    // instead of answering `agent-busy`.
    const resume = vi.spyOn(ctx.agents, 'resume')
      .mockRejectedValue(new Error('registry unavailable in this bench'))
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const prompt = await api.sessions.prompt(request({
      sessionId,
@@ -412,7 +412,7 @@ describe('subagent ownership fence', () => {
    })
    const startingChild = { id: startingSession.id, session: startingSession, status: 'idle', ctx } as Agent
    ctx.agents.enter(startingChild, parent)
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const stopped = await api.sessions.cancel(request({ sessionId: originChild.id }))
    expect(stopped.result.ok).toBe(false)
@@ -458,7 +458,7 @@ describe('subagent ownership fence', () => {
    const followup = vi.fn()
    const agent = { id: session.id, session, status: 'idle', ctx, followup } as unknown as Agent
    ctx.agents.register(agent)
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const response = await api.sessions.prompt(request({
      sessionId: agent.id,
@@ -476,7 +476,7 @@ describe('degenerate composition (no persistence, no factory)', () => {
    await ctx.plugin(SessionStore)
    await ctx.plugin(AgentRegistry)
    await ctx.plugin(UserInteractionService)
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const listed = await api.sessions.list(request({}))
    expect(listed.result.ok).toBe(true)
@@ -501,7 +501,7 @@ describe('degenerate composition (no persistence, no factory)', () => {
      list: () => Promise.resolve([]),
      inspect,
    } as never)
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const response = await api.sessions.history(request({ sessionId: sid('session-missing') }))
    expect(response.result.ok).toBe(false)
@@ -527,7 +527,7 @@ describe('sessions.prompt synchronous rejection', () => {
      followup: () => { throw new Error('agent "session-throwing" lifecycle disposed') },
      steer: () => { throw new Error('agent "session-throwing" lifecycle disposed') },
    } as unknown as Agent)
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    for (const mode of ['queue', 'steer'] as const) {
      const response = await api.sessions.prompt(request({
@@ -571,7 +571,7 @@ describe('sessions.prompt synchronous rejection', () => {
      ctx.agents.register(child)
      throw new Error('session id already published')
    })
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const models = await api.sessions.models(request({ sessionId }))
    expect(models.result.ok).toBe(false)
--- a/packages/host/apiproxy/tests/api-proxy-commands.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-commands.spec.ts
@@ -25,7 +25,7 @@ import type { RpcRequest, RpcResponse } from '../src/api/rpc.ts'
 import { RpcId } from '../src/api/rpc.ts'
 import { createApiProxy } from '../src/api-proxy.ts'

-const DEFAULTS = { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }
+const DEFAULTS = { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }

 function request<P>(payload: P): RpcRequest<P> {
  return { rpcId: RpcId(`req-${String(nextRpc++)}`), payload }
--- a/packages/host/apiproxy/tests/api-proxy-config.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-config.spec.ts
@@ -22,9 +22,10 @@ import type { CredentialInfo, CredentialRef, ResolvedCredential } from '@deepsee
 import type { HostFrame } from '../src/api/index.ts'
 import type { RpcRequest, RpcResponse } from '../src/api/rpc.ts'
 import { RpcId } from '../src/api/rpc.ts'
-import { API_GATEWAY_SETTINGS_NAMESPACE, createApiProxy } from '../src/api-proxy.ts'
+import { AGENT_DEFAULT_MODEL_SETTINGS_NAMESPACE } from '@deepseek-ai/dsh-agent-default-model'
+import { createApiProxy } from '../src/api-proxy.ts'

-const DEFAULTS = { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }
+const DEFAULTS = { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }

 let nextRpc = 1
 function request<P>(payload: P): RpcRequest<P> {
@@ -398,21 +399,21 @@ describe('settings domain', () => {
    expect(frames).toEqual([{ type: 'host/settings-changed', ns: 'permission' }])
  })

-  it('invalidates the model catalog when the gateway default route changes', async () => {
+  it('invalidates the model catalog when the Agent default selection changes', async () => {
    const ctx = await harness()
-    const route = ctx.settings.register(API_GATEWAY_SETTINGS_NAMESPACE, z.object({
+    const defaultModel = ctx.settings.register(AGENT_DEFAULT_MODEL_SETTINGS_NAMESPACE, z.object({
      provider: z.string().required(),
      model: z.string().required(),
    }), { base: { provider: 'deepseek-official', model: 'deepseek-v4-flash' } })
    const api = createApiProxy(ctx, DEFAULTS)
-    // The gateway's own section names the route every session with no logged
-    // one resolves to, so an externally edited default — another tab, a
+    // The shared section names the selection every blank session resolves to,
+    // so an externally edited default — another tab, a
    // hand-edited settings.yaml — has to reach an open selector as well.
    const frames = await collectHost(api, ['host/settings-changed', 'host/models-changed'], 2, async () => {
-      await route.replace({ provider: 'deepseek-official', model: 'deepseek-reasoner' })
+      await defaultModel.replace({ provider: 'deepseek-official', model: 'deepseek-reasoner' })
    })
    expect(frames).toEqual([
-      { type: 'host/settings-changed', ns: 'api-gateway' },
+      { type: 'host/settings-changed', ns: 'agent-default-model' },
      { type: 'host/models-changed' },
    ])
  })
--- a/packages/host/apiproxy/tests/api-proxy-default-route.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-default-route.spec.ts
@@ -1,108 +0,0 @@
-/**
- * The `api-gateway` settings section over a REAL settings provider: the
- * composition entry as the base layer, the wholesale replace the gateway
- * persists with, and the fallback when the provider detaches. The other model
- * specs drive hand-rolled `defaultTarget`/`persistDefaultTarget` closures, so
- * this is the only place the layering itself is exercised.
- */
-
-import { describe, expect, it } from 'vitest'
-import { Context } from 'cordis'
-import { Settings, installSettingsSection } from '@deepseek-ai/dsh-settings'
-import type { SettingsNamespace } from '@deepseek-ai/dsh-settings'
-import { API_GATEWAY_SETTINGS_NAMESPACE, DEFAULT_ROUTE_SCHEMA } from '../src/index.ts'
-import type { DefaultRouteSettings } from '../src/index.ts'
-
-/** The smallest real provider: one in-memory document, always writable. */
-class MemorySettings extends Settings {
-  doc: Record<string, unknown> = {}
-
-  get writable(): boolean {
-    return true
-  }
-
-  protected load(): Promise<Record<string, unknown>> {
-    return Promise.resolve(structuredClone(this.doc))
-  }
-
-  protected persist(ns: SettingsNamespace, section: Record<string, unknown>): Promise<void> {
-    this.doc = { ...this.doc, [ns]: structuredClone(section) }
-    return Promise.resolve()
-  }
-}
-
-/** Mount the gateway's own section wiring over a live provider. */
-async function boot(entry: DefaultRouteSettings) {
-  const ctx = new Context()
-  const fiber = ctx.plugin(MemorySettings)
-  await fiber.await()
-  let route: () => DefaultRouteSettings = () => entry
-  const consumer = ctx.plugin(function section(child: Context) {
-    installSettingsSection(child, API_GATEWAY_SETTINGS_NAMESPACE, DEFAULT_ROUTE_SCHEMA, entry, {
-      setSource: (current) => { route = current },
-      onChange: () => {},
-    })
-  })
-  await consumer.await()
-  const settings = ctx.get('settings')
-  if (settings === undefined) throw new Error('settings provider did not mount')
-  return { ctx, fiber, consumer, settings, read: () => route() }
-}
-
-describe('the api-gateway default-route section', () => {
-  it('resolves the composition entry until the user layer overrides it', async () => {
-    const bench = await boot({ provider: 'deepseek-official', model: 'deepseek-v4-flash' })
-    expect(bench.read()).toEqual({ provider: 'deepseek-official', model: 'deepseek-v4-flash' })
-
-    await bench.settings.replace(API_GATEWAY_SETTINGS_NAMESPACE, {
-      provider: 'acme-gateway', model: 'acme-large', reasoningEffort: 'high',
-    })
-    expect(bench.read()).toEqual({
-      provider: 'acme-gateway', model: 'acme-large', reasoningEffort: 'high',
-    })
-    await bench.ctx.fiber.dispose()
-  })
-
-  it('clears a stored effort when the next switch has none', async () => {
-    const bench = await boot({ provider: 'deepseek-official', model: 'deepseek-v4-flash' })
-    await bench.settings.replace(API_GATEWAY_SETTINGS_NAMESPACE, {
-      provider: 'acme-gateway', model: 'acme-large', reasoningEffort: 'high',
-    })
-    expect(bench.read().reasoningEffort).toBe('high')
-
-    // The whole reason the gateway persists with `replace` rather than a merge
-    // patch — and the reason `Config` carries no effort for the base layer to
-    // re-inherit here. A stranded effort would fail the next session's first
-    // request against a model that does not support it.
-    await bench.settings.replace(API_GATEWAY_SETTINGS_NAMESPACE, {
-      provider: 'acme-gateway', model: 'acme-plain',
-    })
-    expect(bench.read()).toEqual({ provider: 'acme-gateway', model: 'acme-plain' })
-    await bench.ctx.fiber.dispose()
-  })
-
-  it('layers a hand-written partial section over the entry', async () => {
-    const bench = await boot({ provider: 'deepseek-official', model: 'deepseek-v4-flash' })
-    // Someone editing settings.yaml by hand may name only the model. The
-    // entry supplies the provider, which is what makes this legal — and is
-    // exactly why an effort in the entry could never be cleared, so there
-    // is none to inherit.
-    await bench.settings.replace(API_GATEWAY_SETTINGS_NAMESPACE, { model: 'deepseek-reasoner' })
-    expect(bench.read()).toEqual({ provider: 'deepseek-official', model: 'deepseek-reasoner' })
-    await bench.ctx.fiber.dispose()
-  })
-
-  it('falls back to the composition entry when the provider detaches', async () => {
-    const bench = await boot({ provider: 'deepseek-official', model: 'deepseek-v4-flash' })
-    await bench.settings.replace(API_GATEWAY_SETTINGS_NAMESPACE, {
-      provider: 'acme-gateway', model: 'acme-large',
-    })
-    expect(bench.read().provider).toBe('acme-gateway')
-
-    // A deployment that loses its settings provider keeps serving the route it
-    // was composed with rather than the one it can no longer read.
-    await bench.fiber.dispose()
-    expect(bench.read()).toEqual({ provider: 'deepseek-official', model: 'deepseek-v4-flash' })
-    await bench.ctx.fiber.dispose()
-  })
-})
--- a/packages/host/apiproxy/tests/api-proxy-fork.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-fork.spec.ts
@@ -82,7 +82,7 @@ function liveAgent(
 }

 const api = (ctx: Context) => createApiProxy(ctx, {
-  defaultTarget: () => ({ provider: 'default-provider', model: 'default-model' }),
+  defaultModelSelection: () => ({ provider: 'default-provider', model: 'default-model' }),
  cwd: '/tmp',
  workspaceRoot: '/tmp',
 })
@@ -254,7 +254,7 @@ describe('sessions.fork', () => {
    await ctx.fiber.dispose()
  })

-  it('installs the latest logged model target before the child can run', async () => {
+  it('installs the latest logged model selection before the child can run', async () => {
    const ctx = await composed()
    const source = liveAgent(ctx, 'session-routed', 1)
    source.append('request/header', {
--- a/packages/host/apiproxy/tests/api-proxy-models.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-models.spec.ts
@@ -1,6 +1,6 @@
 /**
 * Web session model-directory and selection behavior: dynamic provider grouping,
- * provider-local catalog failures, logged-target restoration without stale
+ * provider-local catalog failures, logged-selection restoration without stale
 * catalog injection, advisory pass-through models, and the prompt-assembly
 * boundary for a running selection change.
 */
@@ -119,13 +119,13 @@ function expectValue<T>(response: { result: { ok: true; value: T } | { ok: false
 }

 describe('Web session model selection', () => {
-  it('groups successful providers and leaves an unlisted current target out of the catalog', async () => {
+  it('groups successful providers and leaves an unlisted current selection out of the catalog', async () => {
    const { ctx, sessionId } = await harness({
      provider: 'deepseek-official',
      model: 'private-preview',
      reasoningEffort: ReasoningEffortId('max'),
    })
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'deepseek-official', model: 'deepseek-chat' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'deepseek-official', model: 'deepseek-chat' }), cwd: '/tmp', workspaceRoot: '/tmp' })

    const catalog = expectValue(await api.sessions.models(request({ sessionId })))
    expect(catalog.current).toEqual({
@@ -160,7 +160,7 @@ describe('Web session model selection', () => {

  it('accepts an advisory-unlisted model, rejects an unavailable provider, and switches only after the next assembly', async () => {
    const { ctx, agent, sessionId } = await harness()
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'deepseek-official', model: 'deepseek-chat' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'deepseek-official', model: 'deepseek-chat' }), cwd: '/tmp', workspaceRoot: '/tmp' })
    const seed: LlmCallConfig = { provider: 'seed', model: 'seed', temperature: 0.2 }
    const signal = new AbortController().signal

@@ -226,11 +226,11 @@ describe('Web session model selection', () => {
    await ctx.fiber.dispose()
  })

-  it('reads the host default live for a session whose log names no route', async () => {
+  it('reads the Agent default live for a session whose log names no selection', async () => {
    const { ctx, sessionId } = await harness()
    let stored = { provider: 'deepseek-official', model: 'deepseek-chat' }
    const api = createApiProxy(ctx, {
-      defaultTarget: () => stored,
+      defaultModelSelection: () => stored,
      cwd: '/tmp',
      workspaceRoot: '/tmp',
    })
@@ -248,14 +248,14 @@ describe('Web session model selection', () => {
    await ctx.fiber.dispose()
  })

-  it('keeps a session that logged a route on it when the host default moves', async () => {
+  it('keeps a session on its logged selection when the Agent default differs', async () => {
    const { ctx, sessionId } = await harness({
      provider: 'deepseek-official',
      model: 'deepseek-chat',
    })
    let stored = { provider: 'deepseek-official', model: 'deepseek-chat' }
    const api = createApiProxy(ctx, {
-      defaultTarget: () => stored,
+      defaultModelSelection: () => stored,
      cwd: '/tmp',
      workspaceRoot: '/tmp',
    })
@@ -271,9 +271,9 @@ describe('Web session model selection', () => {
    const saved: unknown[] = []
    let reject = false
    const api = createApiProxy(ctx, {
-      defaultTarget: () => ({ provider: 'deepseek-official', model: 'deepseek-chat' }),
-      persistDefaultTarget: (target) => {
-        saved.push(target)
+      defaultModelSelection: () => ({ provider: 'deepseek-official', model: 'deepseek-chat' }),
+      saveDefaultModelSelection: (selection) => {
+        saved.push(selection)
        return reject ? Promise.reject(new Error('read-only document')) : Promise.resolve()
      },
      cwd: '/tmp',
@@ -306,7 +306,7 @@ describe('Web session model selection', () => {
  it('refuses a prompt no adapter can route, and reports it on the directory', async () => {
    const { ctx, sessionId } = await harness()
    const api = createApiProxy(ctx, {
-      defaultTarget: () => ({ provider: 'deleted-gateway', model: 'deleted-model' }),
+      defaultModelSelection: () => ({ provider: 'deleted-gateway', model: 'deleted-model' }),
      cwd: '/tmp',
      workspaceRoot: '/tmp',
    })
@@ -339,7 +339,7 @@ describe('Web session model selection', () => {
    const api = createApiProxy(ctx, {
      // What a Models-page removal leaves behind: the settings document still
      // names the route the user last picked, and nothing serves it.
-      defaultTarget: () => ({ provider: 'deleted-gateway', model: 'deleted-model' }),
+      defaultModelSelection: () => ({ provider: 'deleted-gateway', model: 'deleted-model' }),
      cwd: '/tmp',
      workspaceRoot: '/tmp',
    })
--- a/packages/host/apiproxy/tests/api-proxy-projections.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-projections.spec.ts
@@ -68,7 +68,7 @@ function seedMessages(session: Session, count: number): void {
  }
 }

-const api = (ctx: Context) => createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+const api = (ctx: Context) => createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

 describe('session.history projections block', () => {
  it('serves the unit value on the tail page with asOfSeq = last event seq', async () => {
--- a/packages/host/apiproxy/tests/api-proxy-question.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-question.spec.ts
@@ -14,7 +14,7 @@ async function harness(): Promise<{ ctx: Context; api: ApiProxy }> {
  await ctx.plugin(UserInteractionService)
  return {
    ctx,
-    api: createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }),
+    api: createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }),
  }
 }

--- a/packages/host/apiproxy/tests/api-proxy-rename.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-rename.spec.ts
@@ -68,7 +68,7 @@ function liveAgent(ctx: Context, id: string, turns: number): Session {
  return session
 }

-const api = (ctx: Context) => createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+const api = (ctx: Context) => createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })

 describe('sessions.rename', () => {
  it('accepts through the composed title service: normalized user-source event, echoed seq', async () => {
--- a/packages/host/apiproxy/tests/api-proxy-search.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-search.spec.ts
@@ -27,7 +27,7 @@ vi.mock('node:fs/promises', async (importOriginal) => {
 })

 const sid = (value: string): SessionId => value as SessionId
-const defaults = { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }
+const defaults = { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' }

 function request(query: string): RpcRequest<{ query: string }> {
  return { rpcId: RpcId(`search-${query}`), payload: { query } }
--- a/packages/host/apiproxy/tests/api-proxy-subagents.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-subagents.spec.ts
@@ -95,7 +95,7 @@ function bench(options: {
  ctx.provide('sessionProjections', { snapshot, restore, onChanged: () => () => {} })
  ctx.provide('userInteraction', { registerProvider: () => () => {} })
  const api = createApiProxy(ctx, {
-    defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp',
+    defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp',
  })
  return { api, getAgent, listChildren, inspect, snapshot, restore, followup, interrupt, parent }
 }
--- a/packages/host/apiproxy/tests/api-proxy-view.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-view.spec.ts
@@ -105,7 +105,7 @@ async function collect(iterable: AsyncIterable<RpcRequest<MuxFrame>>, count: num
 describe('mux live view computation', () => {
  it('attaches the three standard card views, omits view without a presenter, soft-falls on throw', async () => {
    const { ctx } = await harness()
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
    const abort = new AbortController()
    const stream = api.events.mux({ rpcId: RpcId('t-mux'), payload: {} }, abort.signal)
    const collected = collect(stream, 9, abort)
@@ -170,7 +170,7 @@ describe('mux live view computation', () => {

  it('serves history entries with call/result views, backscan pairing, and soft-falls', async () => {
    const { ctx } = await harness()
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
    const session = ctx.sessions.create()
    // history resolves the agent first; a live structural stub is enough (only
    // .session is read on this path).
@@ -238,7 +238,7 @@ describe('mux live view computation', () => {

  it('counts only append-origin messages toward maxMessages and keeps compaction provenance whole', async () => {
    const { ctx } = await harness()
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
    const session = ctx.sessions.create()
    ctx.agents.register({ id: session.id, session, status: 'idle', ctx } as Agent)
    session.append('turn/start', { turn: 1 })
@@ -287,7 +287,7 @@ describe('mux live view computation', () => {

  it('drops a disposed session from the live open-call table (result after dispose gets no view)', async () => {
    const { ctx } = await harness()
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
    const abort = new AbortController()
    const stream = api.events.mux({ rpcId: RpcId('t-mux3'), payload: {} }, abort.signal)

@@ -308,7 +308,7 @@ describe('mux live view computation', () => {

  it('pairs a result after turn/end via the in-memory backscan fallback', async () => {
    const { ctx } = await harness()
-    const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+    const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
    const abort = new AbortController()
    const stream = api.events.mux({ rpcId: RpcId('t-mux2'), payload: {} }, abort.signal)
    const collected = collect(stream, 4, abort)
--- a/packages/host/apiproxy/tests/api-proxy-workspace.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-workspace.spec.ts
@@ -100,7 +100,7 @@ async function harness(
  // object per harness mirrors the seam's stability contract.
  ctx.provide('directoryPicker', { capability: () => picker } as never)
  const api = createApiProxy(ctx, {
-    defaultTarget: () => ({ provider: 'test', model: 'test-model' }),
+    defaultModelSelection: () => ({ provider: 'test', model: 'test-model' }),
    cwd: workspaceRoot,
    workspaceRoot,
    ...extras.openPath === undefined ? {} : { openPath: extras.openPath },
--- a/packages/host/apiproxy/tests/client-handler.spec.ts
+++ b/packages/host/apiproxy/tests/client-handler.spec.ts
@@ -41,7 +41,7 @@ function scriptedApi(overrides: {
      history: r => ok(r, {
        events: [],
        hasMore: false,
-        modelTarget: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
+        modelSelection: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
      }),
      models: r => ok(r, {
        current: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
--- a/packages/host/apiproxy/tests/rpc-schemas.spec.ts
+++ b/packages/host/apiproxy/tests/rpc-schemas.spec.ts
@@ -192,7 +192,7 @@ describe('sessions domain schemas', () => {
    expect(sessionHistoryValueSchema.parse({
      events: [],
      hasMore: false,
-      modelTarget: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
+      modelSelection: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
    }).hasMore).toBe(false)
    expect(sessionModelsRequestSchema.parse({ sessionId: 's1' }).sessionId).toBe('s1')
    expect(sessionModelsValueSchema.parse({
--- a/packages/host/apiproxy/tsconfig.json
+++ b/packages/host/apiproxy/tsconfig.json
@@ -35,6 +35,9 @@
    {
      "path": "../../core/agent"
    },
+    {
+      "path": "../../core/agent-default-model"
+    },
    {
      "path": "../../core/session"
    },
--- a/packages/self-modification/tool-cordis/src/api-catalog.ts
+++ b/packages/self-modification/tool-cordis/src/api-catalog.ts
@@ -62,6 +62,20 @@ export interface TypeApiEntry {

 /** Every harness `ctx.<key>` service, sorted by key. */
 export const SERVICE_API: readonly ServiceApiEntry[] = [
+  {
+    key: 'agentDefaultModel',
+    summary: 'Owns the default model selection independently of any Host or transport.',
+    methods: [
+      {
+        signature: 'currentSelection(): ModelSelection',
+        jsDoc: '/**\n * Read the current default model selection.\n * @returns a detached provider, model, and optional reasoning selection.\n */',
+      },
+      {
+        signature: 'async saveSelection(next: ModelSelection): Promise<void>',
+        jsDoc: '/**\n * Save the complete default model selection. A deployment without a settings\n * provider keeps its composition entry.\n * @param next - resolved selection accepted by a front door.\n * @returns fulfillment after the optional settings write settles.\n */',
+      },
+    ],
+  },
  {
    key: 'agentLoop',
    summary: 'Concrete agent factory and driver service.',
@@ -2233,6 +2247,10 @@ export const TYPE_API: readonly TypeApiEntry[] = [
    name: 'ModelMessageSource',
    declaration: 'export interface ModelMessageSource extends AssistantProvenance {\n    kind: \'model\';\n}',
  },
+  {
+    name: 'ModelSelection',
+    declaration: 'export interface ModelSelection {\n    provider: string;\n    model: string;\n    reasoningEffort?: ReasoningEffortId;\n}',
+  },
  {
    name: 'ObjectJsonSchema',
    declaration: 'export type ObjectJsonSchema = JsonSchemaNode & {\n    type: \'object\';\n};',
--- a/packages/todo/tool-todo/tests/projection.spec.ts
+++ b/packages/todo/tool-todo/tests/projection.spec.ts
@@ -45,7 +45,7 @@ async function harness(withTodoTool: boolean): Promise<Bench> {
  if (withTodoTool) await ctx.plugin(ToolTodo, { allowParallelInProgress: true })
  const session = ctx.sessions.create()
  ctx.agents.register({ id: session.id, session, status: 'idle', ctx } as Agent)
-  const api = createApiProxy(ctx, { defaultTarget: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
+  const api = createApiProxy(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp', workspaceRoot: '/tmp' })
  return {
    ctx,
    session,