diff --git a/packages/client/ui-agent-preset/README.i18n.yaml b/packages/client/ui-agent-preset/README.i18n.yaml
index 40e443b224..97e553be99 100644
--- a/packages/client/ui-agent-preset/README.i18n.yaml
+++ b/packages/client/ui-agent-preset/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-agent-preset/README.md
-README.md: d775daf1e91c6eb9ebca69c7d0484c0029e93cfc
-README.zh.md: b3fb3e64324dcb78465843ba2ba58f5a3efa3d08
+README.md: be159855010c1a0af7d3f712d9551000826d4820
+README.zh.md: 73c07751f4e5cf1cea43d2723027162f09da10f6
diff --git a/packages/client/ui-agent-preset/README.md b/packages/client/ui-agent-preset/README.md
index 9425b50af9..45e4ceabbb 100644
--- a/packages/client/ui-agent-preset/README.md
+++ b/packages/client/ui-agent-preset/README.md
@@ -24,7 +24,7 @@ The row re-reads on `settings/changed` for its own namespace and on `connection/
 
 ## The management section
 
-A third surface, its own settings page: the roster as rows, and one composition open in a YAML editor at a time.
+A third surface, its own settings page (`settings.section` id `agent-presets`, ordered after Models — choosing a model is routine, composing an agent is the deployment-shaping act behind it): the roster as rows, and one composition open in a YAML editor at a time.
 
 A shipped preset opens read-only. It is the known-good composition a local one is written against, so reading it is the point and overwriting it is not — the deployment's copy is what a broken local preset is compared against. Authoring therefore starts by duplicating: **New preset** copies the current default, and **Duplicate** copies any row, because a copy always lands in the local root regardless of where the text came from.
 
@@ -32,6 +32,8 @@ An id becomes a directory name, so the editor mirrors the host's own containment
 
 Deleting removes the file. Sessions already composed from it keep running — a composition is mounted once at session creation and nothing re-reads the file.
 
+Setting the default writes the `agent-presets` settings namespace, which the host exposes to configuration clients ([`dsh-apiproxy`](../../host/apiproxy/README.md) keeps an explicit allowlist — a namespace outside it makes a picker move and then silently forget).
+
 `agentPreset.read`, `write`, `remove`, and `select` are loopback-pinned ([`dsh-client-connection`](../connection/README.md)): a composition names the plugins a session runs, so reading one is reconnaissance and writing one is arbitrary capability. `agentPreset.list` is not — it carries ids and trust, and a LAN client's picker needs it.
 
 ## When the surfaces are absent
diff --git a/packages/client/ui-agent-preset/README.zh.md b/packages/client/ui-agent-preset/README.zh.md
index c5be1ea017..3552e92675 100644
--- a/packages/client/ui-agent-preset/README.zh.md
+++ b/packages/client/ui-agent-preset/README.zh.md
@@ -24,7 +24,7 @@ agent preset 的各个表层：General 设置中的一行，用于选择新建
 
 ## 管理分区
 
-第三个表层，独立的设置页：名单以行呈现，同一时刻有一份组装在 YAML 编辑器中打开。
+第三个表层，独立的设置页（`settings.section`，id 为 `agent-presets`，排在「模型」之后——选模型是日常操作，而组装 agent 是它背后那件塑造部署形态的事）：名单以行呈现，同一时刻有一份组装在 YAML 编辑器中打开。
 
 随部署提供的 preset 以只读方式打开。它是本地 preset 据以编写的已知良好组装，因此能读到它正是意义所在，而覆写它则不是——部署自带的那一份正是用来对照有问题的本地 preset 的。因此创作从复制开始：**新建 preset** 复制当前默认值，**复制**则复制任意一行；无论文本来自何处，副本总是落在本地根目录，所以副本总是可写的。
 
@@ -32,6 +32,8 @@ id 会成为目录名，因此编辑器复刻宿主自身的约束规则（`[a-z
 
 删除会移除该文件。已据其组装的会话继续运行——组装在会话创建时挂载一次，此后没有任何东西会重新读取该文件。
 
+设置默认值写入的是 `agent-presets` settings 命名空间，宿主需将其暴露给配置客户端（[`dsh-apiproxy`](../../host/apiproxy/README.md) 维护一份显式白名单——不在其中的命名空间会让选择器动一下然后悄悄忘记）。
+
 `agentPreset.read`、`write`、`remove` 与 `select` 被固定在环回地址（见 [`dsh-client-connection`](../connection/README.md)）：组装指明了一个会话所运行的插件，因此读取它是侦察，写入它是任意能力。`agentPreset.list` 不在其中——它只携带 id 与信任级别，而局域网客户端的选择器需要它。
 
 ## 何时不显示这些表层
diff --git a/packages/client/ui-agent-preset/src/client/locales.ts b/packages/client/ui-agent-preset/src/client/locales.ts
index fc97b4d109..95d9c5bb3b 100644
--- a/packages/client/ui-agent-preset/src/client/locales.ts
+++ b/packages/client/ui-agent-preset/src/client/locales.ts
@@ -59,7 +59,7 @@ export const zh: Record<AgentPresetSettingsKey, string> = {
   userTrust: '本地',
   seatHint: '本会话的 agent preset —— 发送第一条消息前可切换',
   lockedHint: '会话开始后，其 agent preset 即固定',
-  nav: 'Agent preset',
+  nav: '智能体',
   sectionIntro: 'preset 即一个会话的 agent 所运行的插件组装 —— 它的工具、提示词与能力。内置 preset 只读；复制一份即可改成自己的。',
   builtIn: '内置',
   defaultBadge: '默认',
diff --git a/packages/client/ui-agent-preset/tests/apply.spec.ts b/packages/client/ui-agent-preset/tests/apply.spec.ts
index 207598f471..40da44c792 100644
--- a/packages/client/ui-agent-preset/tests/apply.spec.ts
+++ b/packages/client/ui-agent-preset/tests/apply.spec.ts
@@ -91,7 +91,7 @@ describe('ui-agent-preset apply', () => {
     expect(section.component).toBe(AgentPresetSection)
     expect(section.options).toMatchObject({ id: 'agent-presets', order: 20 })
     // The nav label is a locale-following thunk; owners resolve it at read time.
-    expect(resolveSlotLabel(section.options.label)).toBe('Agent preset')
+    expect(resolveSlotLabel(section.options.label)).toBe('智能体')
   })
 
   it('registers into a declaration that arrives after apply', async () => {
diff --git a/packages/client/ui-settings/src/client/SettingsRoot.tsx b/packages/client/ui-settings/src/client/SettingsRoot.tsx
index 45055753ac..9e48c7d4b0 100644
--- a/packages/client/ui-settings/src/client/SettingsRoot.tsx
+++ b/packages/client/ui-settings/src/client/SettingsRoot.tsx
@@ -12,13 +12,16 @@
 import { useCallback, useEffect, useId, useRef, useState } from 'react'
 import { createPortal } from 'react-dom'
 import clsx from 'clsx'
-import { IconCloseOutline16, IconDataOutline16, IconSettingsOutline16 } from '@deepseek-ai/dsh-client-ui-primitives'
+import {
+  IconCloseOutline16, IconDataOutline16, IconSettingsOutline16, IconThinkOutline16,
+} from '@deepseek-ai/dsh-client-ui-primitives'
 import type { SettingsRootComponentProps, SettingsSectionRow } from './contract/slots.ts'
 import css from './SettingsRoot.module.css'
 
 /** Nav glyph by section id; unknown ids fall back to the settings gear. */
 function navIcon(id: string) {
   if (id === 'models') return <IconDataOutline16 className={css.navIcon} size={16} />
+  if (id === 'agent-presets') return <IconThinkOutline16 className={css.navIcon} size={16} />
   return <IconSettingsOutline16 className={css.navIcon} size={16} />
 }
 
diff --git a/packages/client/ui-settings/tests/settings-root.spec.tsx b/packages/client/ui-settings/tests/settings-root.spec.tsx
index 900c66d381..732ca4ba81 100644
--- a/packages/client/ui-settings/tests/settings-root.spec.tsx
+++ b/packages/client/ui-settings/tests/settings-root.spec.tsx
@@ -24,6 +24,7 @@ function mount({
   rows = [
     { id: 'general', order: 0, label: 'General' },
     { id: 'models', order: 10, label: 'Models' },
+    { id: 'agent-presets', order: 20, label: 'Agent presets' },
   ],
   steps = [
     { id: 'welcome', order: -100 },
diff --git a/packages/host/apiproxy/src/api-proxy.ts b/packages/host/apiproxy/src/api-proxy.ts
index 353d5a7af8..2285852da2 100644
--- a/packages/host/apiproxy/src/api-proxy.ts
+++ b/packages/host/apiproxy/src/api-proxy.ts
@@ -26,7 +26,8 @@ import {
 // Type-only: brings the `ctx.tools` Context merge into this program (viewFor reads presenters).
 import {
   InvalidCompositionError, InvalidPresetIdError, PresetMountError,
-  PresetNotWritableError, resolveSessionPreset, UnknownPresetError,
+  PresetNotWritableError, resolveSessionPreset,
+  SETTINGS_NAMESPACE as AGENT_PRESET_SETTINGS_NAMESPACE, UnknownPresetError,
 } from '@deepseek-ai/dsh-agent-presets'
 import type {} from '@deepseek-ai/dsh-tools'
 import type {
@@ -89,8 +90,15 @@ const COLD_SUMMARY_BATCH_SIZE = 16
 /** Conversation message event types (the pagination counting unit). */
 const MESSAGE_TYPES = new Set(['user/message', 'assistant/message'])
 
-/** Product settings intentionally exposed beside model-provider namespaces. */
-const PRODUCT_SETTINGS_NAMESPACES = new Set(['ui-onboarding'])
+/**
+ * Product settings intentionally exposed beside model-provider namespaces.
+ *
+ * The agent-preset namespace carries one field — which preset a session with
+ * no explicit choice is composed from — and both browser surfaces that offer
+ * that choice write it through `settings.update`, so it has to cross the
+ * configuration boundary or the pickers silently fail to persist.
+ */
+const PRODUCT_SETTINGS_NAMESPACES = new Set(['ui-onboarding', AGENT_PRESET_SETTINGS_NAMESPACE])
 
 /** Read live abort state across awaits without treating it as synchronously immutable. */
 function isAborted(signal: AbortSignal): boolean {
diff --git a/packages/host/apiproxy/tests/api-proxy-config.spec.ts b/packages/host/apiproxy/tests/api-proxy-config.spec.ts
index 54235c0218..d606c12c4a 100644
--- a/packages/host/apiproxy/tests/api-proxy-config.spec.ts
+++ b/packages/host/apiproxy/tests/api-proxy-config.spec.ts
@@ -355,6 +355,21 @@ describe('settings domain', () => {
     expect(frames).toEqual([{ type: 'host/settings-changed', ns: 'ui-onboarding' }])
   })
 
+  it('serves the agent-preset namespace, so a browser preset picker can persist its choice', async () => {
+    const ctx = await harness()
+    ctx.settings.register(settingsNamespace('agent-presets'), z.object({ default: z.string() }))
+    const api = createApiProxy(ctx, DEFAULTS)
+
+    expectOk(await api.settings.update(request({ ns: 'agent-presets', patch: { default: 'core-web' } })))
+
+    // Both browser surfaces that offer the choice — the General row and the
+    // management section — write the default through `settings.update`, so a
+    // namespace outside this boundary makes the picker move and then silently
+    // forget, which is worse than refusing the control.
+    expect(ctx.settings.describe().find(view => String(view.ns) === 'agent-presets')?.value)
+      .toEqual({ default: 'core-web' })
+  })
+
   it('refuses even a model-provider namespace once its directory entry is gone', async () => {
     const ctx = await harness({ configurableProviders: false })
     ctx.settings.register(NS, AdapterConfig)