Merge remote-tracking branch 'origin/master' into xtr/agent-loop-message-machine

# Conflicts:
#	docs/architecture.i18n.yaml
#	docs/architecture.md
#	docs/architecture.zh.md
#	docs/cordis-catalog/services.md
#	docs/core-data-structures/core.i18n.yaml
#	docs/core-data-structures/core.md
#	docs/core-data-structures/core.zh.md
#	docs/core-data-structures/llm-streaming.i18n.yaml
#	docs/core-data-structures/session.i18n.yaml
#	docs/event-producer-consumer.md
#	examples/acp-agent/tests/snapshots/cordis-inspect-jsdoc/session.jsonl
#	examples/headless-agent/tests/snapshots/advanced-toolchain/session.1.jsonl
#	examples/headless-agent/tests/snapshots/advanced-toolchain/session.2.jsonl
#	packages/core/agent-loop/README.i18n.yaml
#	packages/core/agent-loop/README.md
#	packages/core/agent-loop/README.zh.md
#	packages/core/agent-loop/src/loop.ts
#	packages/core/agent/README.i18n.yaml
#	packages/core/agent/tests/llm-target.spec.ts
#	packages/core/session/tests/request-header.spec.ts

packages/llm/llm/README.i18n.yaml

@@ -1,6 +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
-README.md: 981f7d58802d2ff18633b09b5a4ec8a7b1bf3383
-README.zh.md: 0a6535f41adb8ec90d02dbb56aec257853a19083
+#   pnpm run verify-translation-pairing --write packages/llm/llm/README.md
+README.md: 3efb3ece3caadeaceaa3c504ba4b10ddb951127a
+README.zh.md: 4af8b8d08cc96ff0e36b10b15e1d86afd43004c9

packages/llm/llm/README.md

@@ -13,14 +13,18 @@ An adapter registry plus a single streaming call surface, interceptable via a wa
 - `ctx.llm.registerAdapter(providers: string[], adapter: LlmAdapter): () => void` Register one adapter instance for the given provider routes. Registration is all-or-nothing, and is disposed with the calling fiber.
 - `ctx.llm.listProviders(): LlmProviderInfo[]` Describe registered provider routes in registration order.
 - `ctx.llm.listModels(provider: string): Promise<LlmModelInfo[]>` Discover the models one registered provider currently advertises.
-- `ctx.llm.resolveModelContext(provider: string, model: string): Promise<LlmModelContext | undefined>` Resolve authoritative context capacity for one exact route from its owning adapter.
+- `ctx.llm.resolveModelInfo(provider: string, model: string, signal?: AbortSignal): Promise<LlmResolvedModelInfo>` Resolve validated exact-model identity plus available context and reasoning metadata from the owning adapter, with optional cancellation for asynchronous adapters.
+- `ctx.llm.resolveCallConfig(config: LlmCallConfig, signal?: AbortSignal): Promise<LlmCallConfig>` Validate an explicit effort and materialize an adapter-configured default without clamping.
+- `ctx.llm.prepareCall(config: LlmCallConfig, signal?: AbortSignal): Promise<PreparedLlmCall>` Resolve a config and capture its current adapter registration as one cancellable, one-shot call.
 - `ctx.llm.stream(options: GenerateOptions): AsyncIterable<StreamChunk>` Stream one model call as raw chunks (token-level deltas). Consumers assemble the chunks into blocks/messages with `BlockAssembler`.
 
 `LlmService` preserves errors from final adapter selection, synchronous dispatch, iterator construction, and iteration, and binds their provenance to the exact stream handle returned for that model call. `isLlmAdapterFailure(stream, value)` reports only errors from that call's final adapter boundary; `llmFailureOf(stream, value)` returns the adjacent immutable `LlmFailure`. Nested model calls, `llm/stream` middleware, and downstream consumer failures remain unclassified for the outer call. Classification never replaces or mutates the adapter's original coded `Error`.
 
 Provider and model metadata is a discovery surface, not a routing whitelist. `registerAdapter()` still owns provider exclusivity, while an adapter may accept model ids absent from `listModels()`; consumers must not reject a request because its model is unlisted. Returned metadata is detached and invalid or duplicate adapter entries fail with `INVALID_ADAPTER` or `INVALID_CATALOG`.
 
-Context capacity is a separate correctness query, not a catalog decoration or global LLM setting. `resolveModelContext()` asks the adapter that owns the exact provider/model route; an adapter can describe an unlisted dynamic model, and `undefined` means only that capacity is unavailable. Invalid returned capacity fails with `INVALID_MODEL_CONTEXT`.
+Exact-model metadata is a separate correctness query, not a catalog decoration or global LLM setting. `resolveModelInfo()` asks the adapter that owns the exact provider/model route once; an adapter can describe an unlisted dynamic model, and absent `context` or `reasoning` fields mean only that those capabilities are unavailable. Invalid identity, context, or reasoning metadata fails with `INVALID_MODEL_INFO`, `INVALID_MODEL_CONTEXT`, or `INVALID_MODEL_REASONING`.
+
+Reasoning identifiers are opaque adapter-owned strings rather than a core enum. An adapter publishes its ordered selectable list, including an `off` id when that model's capability API exposes one. `resolveCallConfig()` accepts only an exact advertised identifier, materializes `defaultEffort` when present, and otherwise preserves the provider default. Asynchronous model resolvers receive the caller's signal and must settle promptly after cancellation. `prepareCall()` additionally retains the exact adapter registration through header logging and terminal dispatch, so HMR cannot combine one adapter's capability result with another adapter's request; reusing its one-shot handle or changing its call-config fields fails with `INVALID_PREPARED_CALL`. An unsupported explicit or configured effort fails with `UNSUPPORTED_REASONING_EFFORT` before provider I/O.
 
 ### Events
 
@@ -30,7 +34,7 @@ Context capacity is a separate correctness query, not a catalog decoration or gl
 
 ### Extension points
 
-- Subclass `LlmAdapter` and call `ctx.llm.registerAdapter(providers, adapter)` to add one or more provider routes. `GenerateOptions.provider` selects the adapter; `GenerateOptions.model` is adapter-owned and may be resolved dynamically. Override `providerInfo()` and asynchronous `listModels()` to expose selector metadata, and `resolveModelContext()` when exact capacity is known; the defaults use the route id as its name, advertise no models, and return no capacity.
+- Subclass `LlmAdapter` and call `ctx.llm.registerAdapter(providers, adapter)` to add one or more provider routes. `GenerateOptions.provider` selects the adapter; `GenerateOptions.model` is adapter-owned and may be resolved dynamically. Override `providerInfo()` and asynchronous `listModels()` to expose selector metadata, then implement `resolveModel()` when exact identity, capacity, or selectable reasoning efforts are available; an asynchronous resolver must honor its optional cancellation signal. The defaults use the route and model ids as names, advertise no models, and return no capacity or reasoning metadata.
 - Wrap `llm/stream` via `ctx.on()` waterfall listeners for caching, logging, or routing. A wrapper that retries after emitting a chunk has no durable attempt boundary; shipped agent retry policy therefore uses `agent/request-error` instead.
 
 ### Content-block vocabulary (`types.ts`)
@@ -41,7 +45,7 @@ Streaming is a raw chunk protocol (`block-start`, `text-delta`, `reasoning-delta
 
 ### Call configuration (`call-config.ts`)
 
-`LlmCallConfig` is the provider + model + sampling scalars of one conversation's requests (`provider`, `model`, `temperature`, `maxTokens`, `stop` — each mapping 1:1 onto the same-named `GenerateOptions` field). It is per-conversation state recorded in the session log as part of the request header (see the dsh-session `request/header` events), never a silently-adjustable per-call knob: the `agent/request` waterfall proposes a replacement and the loop logs a real change. `callConfigEquals(a, b)` is the field-wise real-change detector; `deepFreeze(value)` is the ownership helper the loop applies to every built request before dispatch (`llm/stream` listeners and adapters read, never rewrite). `markAgentLoopRequest()` gives that exact object process-local loop provenance, and `isAgentLoopRequest()` lets observers distinguish it from independently logged auxiliary calls that may also be frozen and session-associated. `GenerateOptions.purpose` classifies logged auxiliary compaction and session-title calls so adapters can apply purpose-specific transport policy without changing ordinary conversation requests.
+`LlmCallConfig` is the provider, model, optional adapter-owned reasoning effort, and sampling scalars of one conversation's requests (`provider`, `model`, `reasoningEffort`, `temperature`, `maxTokens`, `stop` — each mapping 1:1 onto the same-named `GenerateOptions` field). It is per-conversation state recorded in the session log as part of the request header (see the dsh-session `request/header` events), never a silently-adjustable per-call knob: the `agent/request` waterfall proposes a replacement, `prepareCall()` validates and defaults it under the turn signal, and the loop logs the effective value before using the prepared call's registration-bound stream. `callConfigEquals(a, b)` is the field-wise real-change detector; `deepFreeze(value)` is the ownership helper the loop applies to every built request before dispatch (`llm/stream` listeners and adapters read, never rewrite). `markAgentLoopRequest()` gives that exact object process-local loop provenance, and `isAgentLoopRequest()` lets observers distinguish it from independently logged auxiliary calls that may also be frozen and session-associated. `GenerateOptions.purpose` classifies logged auxiliary compaction and session-title calls so adapters can apply purpose-specific transport policy without changing ordinary conversation requests.
 
 ### App attribution (`attribution.ts`)
 
@@ -60,11 +64,11 @@ Every product adapter sends application identity on provider HTTP requests. `att
 
 ### Real adapters
 
-Two adapters implement `LlmAdapter` on different internals: [`@deepseek-ai/dsh-llm-deepseek`](../llm-deepseek) uses hand-rolled fetch/SSE for the `deepseek` route, while [`@deepseek-ai/dsh-llm-pi-ai`](../llm-pi-ai) dynamically resolves configured provider/model pairs through `@earendil-works/pi-ai`. Both follow the `StreamChunk` conventions in `types.ts`: usage precedes finish, tool arguments remain raw strings, and errors take one of two sanctioned paths. See [the twin LLM adapters](../../../.agents/notes/implemented/architecture/2026-06-13-twin-llm-adapters.md) for the design rationale.
+Two adapters implement `LlmAdapter` on different internals: [`@deepseek-ai/dsh-llm-deepseek`](../llm-deepseek) uses direct fetch with `eventsource-parser` SSE framing for the `deepseek` route, while [`@deepseek-ai/dsh-llm-pi-ai`](../llm-pi-ai) dynamically resolves configured provider/model pairs through `@earendil-works/pi-ai`. Both follow the `StreamChunk` conventions in `types.ts`: usage precedes finish, tool arguments remain raw strings, and errors take one of two sanctioned paths. See [the twin LLM adapters](../../../.agents/notes/implemented/architecture/2026-06-13-twin-llm-adapters.md) for the design rationale.
 
 ## Model Experience
 
-None, as this adapter registry forwards an already assembled request without adding or changing any model-bound text, schema, or message.
+None, as the service adds no model-bound text, schema, or message; it only materializes and logs an adapter-configured reasoning effort.
 
 #### KV Cache effect
 

packages/llm/llm/README.zh.md

@@ -13,14 +13,18 @@
 - `ctx.llm.registerAdapter(providers: string[], adapter: LlmAdapter): () => void` 为给定提供方路由注册一个适配器实例。注册要么全部成功，要么全部不生效，并且会随调用 fiber dispose。
 - `ctx.llm.listProviders(): LlmProviderInfo[]` 按注册顺序描述已注册提供方路由。
 - `ctx.llm.listModels(provider: string): Promise<LlmModelInfo[]>` 发现某个已注册提供方当前公布的模型。
-- `ctx.llm.resolveModelContext(provider: string, model: string): Promise<LlmModelContext | undefined>` 从拥有精确路由的适配器解析权威上下文容量。
+- `ctx.llm.resolveModelInfo(provider: string, model: string, signal?: AbortSignal): Promise<LlmResolvedModelInfo>` 从拥有精确路由的适配器解析经校验的确切模型身份、可用上下文和推理（reasoning）元数据；异步适配器可选地支持取消。
+- `ctx.llm.resolveCallConfig(config: LlmCallConfig, signal?: AbortSignal): Promise<LlmCallConfig>` 校验显式推理强度，并填入适配器配置的默认值，但不自动调整。
+- `ctx.llm.prepareCall(config: LlmCallConfig, signal?: AbortSignal): Promise<PreparedLlmCall>` 解析配置并将其当前适配器注册捕获为一次可取消、一次性调用。
 - `ctx.llm.stream(options: GenerateOptions): AsyncIterable<StreamChunk>` 将一次模型调用流式输出为原始 chunk（token 级 delta）。消费方使用 `BlockAssembler` 将 chunk 组装为块／消息。
 
 `LlmService` 保留来自最终适配器选择、同步 dispatch、iterator 构造与迭代的错误，并将其溯源绑定到该次模型调用返回的精确流句柄。`isLlmAdapterFailure(stream, value)` 只报告该调用最终适配器边界的错误；`llmFailureOf(stream, value)` 返回相邻的不可变 `LlmFailure`。嵌套模型调用、`llm/stream` middleware 和下游消费方失败对外层调用仍未分类。分类绝不替换或更改适配器的原始编码 `Error`。
 
 提供方与模型元数据是发现表层，不是路由白名单。`registerAdapter()` 仍拥有提供方排他性，适配器则可以接受 `listModels()` 中不存在的模型 id；消费方禁止因模型未列出而拒绝请求。返回的元数据与输入脱离，无效或重复适配器配置项会以 `INVALID_ADAPTER` 或 `INVALID_CATALOG` 失败。
 
-上下文容量是独立的正确性查询，不是 catalog 装饰或全局 LLM 设置。`resolveModelContext()` 会询问拥有精确提供方／模型路由的适配器；适配器可以描述未列出的动态模型，`undefined` 只表示容量不可用。无效的返回容量以 `INVALID_MODEL_CONTEXT` 失败。
+确切模型元数据是独立的正确性查询，不是 catalog 装饰或全局 LLM 设置。`resolveModelInfo()` 会向拥有精确提供方／模型路由的适配器查询一次；适配器可以描述未列出的动态模型，缺少 `context` 或 `reasoning` 字段只表示相应能力不可用。无效的身份、上下文或推理元数据会以 `INVALID_MODEL_INFO`、`INVALID_MODEL_CONTEXT` 或 `INVALID_MODEL_REASONING` 失败。
+
+推理标识符是由适配器持有的不透明字符串，而非核心枚举。适配器会公布有序可选列表；模型能力 API 提供 `off` id 时，列表也会包含它。`resolveCallConfig()` 只接受与已公布标识符完全一致的值，在存在 `defaultEffort` 时填入它，否则保留提供方默认值。异步模型解析器会接收调用方的 signal，并且必须在取消后迅速完成结算。`prepareCall()` 还会让精确适配器注册跨越请求头记录和最终分派，因此 HMR（热模块替换）不会将一个适配器的能力结果与另一个适配器的请求混用；复用其一次性句柄或更改调用配置字段会以 `INVALID_PREPARED_CALL` 失败。不支持的显式或配置推理强度会在提供方 I/O 前以 `UNSUPPORTED_REASONING_EFFORT` 失败。
 
 ### 事件
 
@@ -30,7 +34,7 @@
 
 ### 扩展点
 
-- 继承 `LlmAdapter` 并调用 `ctx.llm.registerAdapter(providers, adapter)`，添加一条或多条提供方路由。`GenerateOptions.provider` 选择适配器；`GenerateOptions.model` 属于适配器，可以动态解析。覆盖 `providerInfo()` 和异步 `listModels()` 以公开 selector 元数据，在已知精确容量时覆盖 `resolveModelContext()`；默认实现将路由 id 用作名称，不公布模型，也不返回容量。
+- 继承 `LlmAdapter` 并调用 `ctx.llm.registerAdapter(providers, adapter)`，添加一条或多条提供方路由。`GenerateOptions.provider` 选择适配器；`GenerateOptions.model` 属于适配器，可以动态解析。覆盖 `providerInfo()` 和异步 `listModels()` 以公开 selector 元数据；精确身份、容量或可选推理强度可用时，实现 `resolveModel()`；异步解析器必须响应其可选的取消 signal。默认实现将路由和模型 id 用作名称，不公布模型，也不返回容量或推理元数据。
 - 包装 `llm/stream` 时，通过 `ctx.on()` waterfall listener 实现缓存、日志或路由。发出 chunk 后重试的包装层没有持久尝试边界；因此已发布 agent 重试策略改用 `agent/request-error`。
 
 ### 内容块词汇（`types.ts`）
@@ -41,7 +45,7 @@
 
 ### 调用配置（`call-config.ts`）
 
-`LlmCallConfig` 是一个会话请求的提供方 + 模型 + 采样标量（`provider`、`model`、`temperature`、`maxTokens`、`stop`，每个都与同名 `GenerateOptions` 字段 1:1 映射）。它是作为请求标头一部分记录在会话日志中的每会话状态（见 dsh-session `request/header` 事件），绝不是可静默调整的每次调用旋钮：`agent/request` waterfall 会提议替换，loop 则记录真实变更。`callConfigEquals(a, b)` 是逐字段真实变更检测器；`deepFreeze(value)` 是 loop 在 dispatch 前对每个已构建请求应用的所有权 helper（`llm/stream` listener 与适配器只读，绝不改写）。`markAgentLoopRequest()` 为该精确对象添加进程本地 loop 溯源，`isAgentLoopRequest()` 让观测方可以将其与同样可能冻结并关联会话、但独立记录的辅助调用区分。`GenerateOptions.purpose` 对已记录辅助压缩与会话标题调用分类，让适配器可以应用目的特定传输策略，而不改变普通会话请求。
+`LlmCallConfig` 是一个会话请求的提供方、模型、可选的适配器持有推理强度和采样标量（`provider`、`model`、`reasoningEffort`、`temperature`、`maxTokens`、`stop`，每个都与同名 `GenerateOptions` 字段 1:1 映射）。它是作为请求标头一部分记录在会话日志中的每会话状态（见 dsh-session `request/header` 事件），绝不是可静默调整的每次调用旋钮：`agent/request` waterfall 会提议替换，`prepareCall()` 在轮次 signal 控制下校验并填入默认值，loop 随后记录生效值，再使用准备完成调用的注册绑定流。`callConfigEquals(a, b)` 是逐字段真实变更检测器；`deepFreeze(value)` 是 loop 在 dispatch 前对每个已构建请求应用的所有权 helper（`llm/stream` listener 与适配器只读，绝不改写）。`markAgentLoopRequest()` 为该精确对象添加进程本地 loop 溯源，`isAgentLoopRequest()` 让观测方可以将其与同样可能冻结并关联会话、但独立记录的辅助调用区分。`GenerateOptions.purpose` 对已记录辅助压缩与会话标题调用分类，让适配器可以应用目的特定传输策略，而不改变普通会话请求。
 
 ### 应用归因（`attribution.ts`）
 
@@ -60,11 +64,11 @@
 
 ### 真实适配器
 
-两个适配器使用不同内部机制实现 `LlmAdapter`：[`@deepseek-ai/dsh-llm-deepseek`](../llm-deepseek) 针对 `deepseek` 路由使用手写 fetch/SSE，[`@deepseek-ai/dsh-llm-pi-ai`](../llm-pi-ai) 则通过 `@earendil-works/pi-ai` 动态解析已配置提供方／模型对。两者都遵循 `StreamChunk` 约定，定义见 `types.ts`：usage 先于 finish，工具参数保持原始字符串，错误使用两种已批准路径之一。设计理由见 [双 LLM 适配器](../../../.agents/notes/implemented/architecture/2026-06-13-twin-llm-adapters.md)。
+两个适配器使用不同内部机制实现 `LlmAdapter`：[`@deepseek-ai/dsh-llm-deepseek`](../llm-deepseek) 针对 `deepseek` 路由使用直接 fetch 加 `eventsource-parser` SSE 分帧，[`@deepseek-ai/dsh-llm-pi-ai`](../llm-pi-ai) 则通过 `@earendil-works/pi-ai` 动态解析已配置提供方／模型对。两者都遵循 `StreamChunk` 约定，定义见 `types.ts`：usage 先于 finish，工具参数保持原始字符串，错误使用两种已批准路径之一。设计理由见 [双 LLM 适配器](../../../.agents/notes/implemented/architecture/2026-06-13-twin-llm-adapters.md)。
 
 ## 模型体验
 
-无。该适配器注册表转发已组装的请求，不添加或更改任何模型边界文本、schema 或消息。
+无。服务不添加或更改任何模型边界文本、schema 或消息；它只会填入并记录适配器配置的推理强度。
 
 #### KV Cache 影响
 

packages/llm/llm/src/brand.ts

@@ -38,3 +38,15 @@ export type ProviderRequestId = Branded<'ProviderRequestId'>
 export function ProviderRequestId(id: string): ProviderRequestId {
   return id as ProviderRequestId
 }
+
+/** Adapter-owned identifier for one model's selectable reasoning effort. */
+export type ReasoningEffortId = Branded<'ReasoningEffortId'>
+
+/**
+ * Brand an adapter-owned reasoning-effort identifier.
+ * @param id - the opaque identifier exposed by one model capability.
+ * @returns the same string, branded; no validation is performed.
+ */
+export function ReasoningEffortId(id: string): ReasoningEffortId {
+  return id as ReasoningEffortId
+}

packages/llm/llm/src/call-config.ts

@@ -1,24 +1,27 @@
 /**
  * Conversation call configuration and freeze utilities. Provider routing,
- * model, and sampling values are request-header state that can affect cache
- * reuse; request waterfalls replace them and the loop logs changed snapshots
- * instead of allowing silent per-call drift.
+ * model, reasoning effort, and sampling values are request-header state that
+ * can affect cache reuse; request waterfalls replace them and the loop logs
+ * changed snapshots instead of allowing silent per-call drift.
  * @module dsh-llm/call-config
  */
 
 import type { GenerateOptions } from './types.ts'
+import type { ReasoningEffortId } from './brand.ts'
 
 /** Process-local identities of request objects assembled by dsh-agent-loop. */
 const AGENT_LOOP_REQUESTS = new WeakSet<GenerateOptions>()
 
 /**
- * Provider + model + sampling scalars of one conversation's requests. Every field maps
- * 1:1 onto the same-named `GenerateOptions` field; the loop builds requests
- * from the logged header rather than accepting these per call.
+ * Provider, model, reasoning effort, and sampling scalars of one conversation's
+ * requests. Every field maps 1:1 onto the same-named `GenerateOptions` field;
+ * the loop builds requests from the logged header rather than accepting these
+ * per call.
  */
 export interface LlmCallConfig {
   provider: string
   model: string
+  reasoningEffort?: ReasoningEffortId
   temperature?: number
   maxTokens?: number
   stop?: string[]
@@ -33,7 +36,13 @@ export interface LlmCallConfig {
  * @returns whether every field (including the `stop` list, element-wise) matches.
  */
 export function callConfigEquals(a: LlmCallConfig, b: LlmCallConfig): boolean {
-  if (a.provider !== b.provider || a.model !== b.model || a.temperature !== b.temperature || a.maxTokens !== b.maxTokens) return false
+  if (
+    a.provider !== b.provider
+    || a.model !== b.model
+    || a.reasoningEffort !== b.reasoningEffort
+    || a.temperature !== b.temperature
+    || a.maxTokens !== b.maxTokens
+  ) return false
   if (a.stop === undefined || b.stop === undefined) return a.stop === b.stop
   return a.stop.length === b.stop.length && a.stop.every((s, i) => s === b.stop?.[i])
 }

packages/llm/llm/src/index.ts

@@ -10,14 +10,15 @@ import { Context, Service } from 'cordis'
 import type {
   GenerateOptions,
   LlmFailure,
-  LlmModelContext,
   LlmModelInfo,
+  LlmResolvedModelInfo,
   LlmProviderInfo,
   Message,
   StreamChunk,
 } from './types.ts'
 import type { ProviderRequestId } from './brand.ts'
-import { deepFreeze } from './call-config.ts'
+import { callConfigEquals, deepFreeze } from './call-config.ts'
+import type { LlmCallConfig } from './call-config.ts'
 import { HarnessError } from './error.ts'
 import { bindAdapterFailureScope, markLlmAdapterFailure } from './adapter-failure.ts'
 import type { AdapterFailureScope } from './adapter-failure.ts'
@@ -103,11 +104,25 @@ export class LlmError extends HarnessError {
   }
 }
 
+/** One model call whose config and adapter registration were resolved together. */
+export interface PreparedLlmCall {
+  /** Detached, deep-frozen config with any adapter-owned default materialized. */
+  readonly config: LlmCallConfig
+  /**
+   * Dispatch this call once through the registration captured during
+   * preparation. The request's call-config fields must match {@link config};
+   * reuse or mismatch fails with `INVALID_PREPARED_CALL`.
+   * @param options - fully assembled request carrying the prepared config.
+   * @returns the chunk stream, including the `llm/stream` waterfall.
+   */
+  stream(options: GenerateOptions): AsyncIterable<StreamChunk>
+}
+
 /**
  * Provider-wire adapter for the harness message and stream vocabulary. Register implementations
  * with `ctx.llm.registerAdapter(providers, adapter)`. Every provider HTTP request must include
- * `attributionHeaders()`; prove that at the wire or library header-hook boundary. The hand-rolled
- * DeepSeek and pi-ai adapters intentionally exercise this contract through different internals.
+ * `attributionHeaders()`; prove that at the wire or library header-hook boundary. The direct-fetch
+ * DeepSeek and library-backed pi-ai adapters intentionally exercise this contract through different internals.
  */
 export abstract class LlmAdapter {
   /**
@@ -131,17 +146,20 @@ export abstract class LlmAdapter {
   }
 
   /**
-   * Resolve context capacity for one model accepted by this adapter. Absence
-   * means the adapter does not know the capacity, not that routing is invalid.
-   * @param _provider - one provider route owned by this adapter.
-   * @param _model - exact model id passed to {@link GenerateOptions.model}.
-   * @returns provider-owned context metadata, or `undefined` when unavailable.
+   * Resolve all metadata available for one exact model. This query is
+   * independent of the advisory catalog and does not validate request routing.
+   * @param provider - one provider route owned by this adapter.
+   * @param model - exact model id passed to {@link GenerateOptions.model}.
+   * @param _signal - cancellation for this exact-model lookup; asynchronous
+   *   implementations must settle promptly after it aborts.
+   * @returns provider/model identity plus any context and reasoning metadata.
    */
-  resolveModelContext(
-    _provider: string,
-    _model: string,
-  ): Promise<LlmModelContext | undefined> {
-    return Promise.resolve(undefined)
+  resolveModel(
+    provider: string,
+    model: string,
+    _signal?: AbortSignal,
+  ): Promise<LlmResolvedModelInfo> {
+    return Promise.resolve({ provider, id: model, name: model })
   }
 
   /**
@@ -157,7 +175,7 @@ export abstract class LlmAdapter {
  * surface, interceptable via the `llm/stream` waterfall.
  */
 export class LlmService extends Service {
-  private adapters = new Map<string, { adapter: LlmAdapter; provider: LlmProviderInfo }>()
+  private adapters = new Map<string, AdapterRegistration>()
 
   constructor(ctx: Context) {
     super(ctx, 'llm')
@@ -175,7 +193,7 @@ export class LlmService extends Service {
     const dispose = this.ctx.effect(function* (this: LlmService) {
       if (providers.length === 0) throw new LlmError('an adapter must register at least one provider', 'INVALID_ADAPTER')
       const unique = new Set<string>()
-      const registrations: { adapter: LlmAdapter; provider: LlmProviderInfo }[] = []
+      const registrations: AdapterRegistration[] = []
       for (const provider of providers) {
         if (provider.length === 0) throw new LlmError('adapter provider names must be non-empty', 'INVALID_ADAPTER')
         if (unique.has(provider) || this.adapters.has(provider)) {
@@ -240,29 +258,170 @@ export class LlmService extends Service {
   }
 
   /**
-   * Resolve context capacity from the adapter that owns one exact route.
-   * This query is independent of the advisory model catalog: an unlisted model
-   * may return metadata, while `undefined` never rejects later routing.
+   * Resolve and validate all metadata from the adapter that owns one exact
+   * route. The result is detached from adapter-owned objects; catalog
+   * membership remains advisory and does not control request routing.
    * @param provider - registered provider route to inspect.
    * @param model - exact model id passed to the adapter.
-   * @returns detached context metadata, or `undefined` when the adapter has none.
+   * @param signal - optional cancellation for adapter-owned asynchronous lookup.
+   * @returns exact model identity plus available context and reasoning metadata.
    */
-  async resolveModelContext(
+  async resolveModelInfo(
     provider: string,
     model: string,
-  ): Promise<LlmModelContext | undefined> {
-    const context = await this.registration(provider).adapter.resolveModelContext(provider, model)
-    if (context === undefined) return undefined
-    if (!Number.isInteger(context.contextWindow) || context.contextWindow <= 0) {
+    signal?: AbortSignal,
+  ): Promise<LlmResolvedModelInfo> {
+    return this.resolveModelInfoFor(this.registration(provider), model, signal)
+  }
+
+  private async resolveModelInfoFor(
+    registration: AdapterRegistration,
+    model: string,
+    signal?: AbortSignal,
+  ): Promise<LlmResolvedModelInfo> {
+    const provider = registration.provider.id
+    const resolved = await registration.adapter.resolveModel(provider, model, signal)
+    if (
+      typeof resolved.provider !== 'string'
+      || resolved.provider !== provider
+      || typeof resolved.id !== 'string'
+      || resolved.id !== model
+      || typeof resolved.name !== 'string'
+      || resolved.name.length === 0
+      || (resolved.description !== undefined && typeof resolved.description !== 'string')
+    ) {
+      throw new LlmError(
+        `adapter returned invalid exact model metadata for provider "${provider}" model "${model}"`,
+        'INVALID_MODEL_INFO',
+      )
+    }
+    const context = resolved.context
+    if (context !== undefined && (!Number.isInteger(context.contextWindow) || context.contextWindow <= 0)) {
       throw new LlmError(
         `adapter returned invalid context metadata for provider "${provider}" model "${model}"`,
         'INVALID_MODEL_CONTEXT',
       )
     }
-    return { contextWindow: context.contextWindow }
+    const info: LlmResolvedModelInfo = {
+      provider,
+      id: model,
+      name: resolved.name,
+      ...resolved.description === undefined ? {} : { description: resolved.description },
+      ...context === undefined ? {} : { context: { contextWindow: context.contextWindow } },
+    }
+    const reasoning = resolved.reasoning
+    if (reasoning === undefined) return info
+    if (reasoning.efforts.length === 0) {
+      throw new LlmError(
+        `adapter returned invalid reasoning metadata for provider "${provider}" model "${model}"`,
+        'INVALID_MODEL_REASONING',
+      )
+    }
+    const seen = new Set<string>()
+    const efforts = reasoning.efforts.map((effort) => {
+      if (
+        typeof effort.id !== 'string'
+        || effort.id.length === 0
+        || typeof effort.name !== 'string'
+        || effort.name.length === 0
+        || (effort.description !== undefined && typeof effort.description !== 'string')
+        || seen.has(effort.id)
+      ) {
+        throw new LlmError(
+          `adapter returned invalid or duplicate reasoning effort metadata for provider "${provider}" model "${model}"`,
+          'INVALID_MODEL_REASONING',
+        )
+      }
+      seen.add(effort.id)
+      return {
+        id: effort.id,
+        name: effort.name,
+        ...effort.description === undefined ? {} : { description: effort.description },
+      }
+    })
+    if (reasoning.defaultEffort !== undefined && !seen.has(reasoning.defaultEffort)) {
+      throw new LlmError(
+        `adapter returned an unknown default reasoning effort for provider "${provider}" model "${model}"`,
+        'INVALID_MODEL_REASONING',
+      )
+    }
+    return {
+      ...info,
+      reasoning: {
+        efforts,
+        ...reasoning.defaultEffort === undefined ? {} : { defaultEffort: reasoning.defaultEffort },
+      },
+    }
   }
 
-  private registration(provider: string): { adapter: LlmAdapter; provider: LlmProviderInfo } {
+  /**
+   * Validate a conversation call config against its exact model capability and
+   * materialize an adapter-configured default. Unsupported explicit efforts
+   * reject before provider I/O; no clamping or aliasing is performed. This
+   * standalone query does not bind a later dispatch; use {@link prepareCall}
+   * when logging and streaming must share one adapter registration.
+   * @param config - provider/model route and optional request controls.
+   * @param signal - optional cancellation for adapter-owned capability lookup.
+   * @returns a detached config only when a default must be materialized.
+   */
+  async resolveCallConfig(config: LlmCallConfig, signal?: AbortSignal): Promise<LlmCallConfig> {
+    return this.resolveCallConfigFor(this.registration(config.provider), config, signal)
+  }
+
+  private async resolveCallConfigFor(
+    registration: AdapterRegistration,
+    config: LlmCallConfig,
+    signal?: AbortSignal,
+  ): Promise<LlmCallConfig> {
+    const reasoning = (await this.resolveModelInfoFor(registration, config.model, signal)).reasoning
+    const requested = config.reasoningEffort
+    if (reasoning === undefined) {
+      if (requested !== undefined) {
+        throw new LlmError(
+          `provider "${config.provider}" model "${config.model}" does not support reasoning effort "${requested}"`,
+          'UNSUPPORTED_REASONING_EFFORT',
+        )
+      }
+      return config
+    }
+    const effective = requested ?? reasoning.defaultEffort
+    if (effective === undefined) return config
+    if (!reasoning.efforts.some(effort => effort.id === effective)) {
+      throw new LlmError(
+        `provider "${config.provider}" model "${config.model}" does not support reasoning effort "${effective}"`,
+        'UNSUPPORTED_REASONING_EFFORT',
+      )
+    }
+    return requested === effective ? config : { ...config, reasoningEffort: effective }
+  }
+
+  /**
+   * Resolve one call under its current adapter registration. The returned
+   * one-shot handle keeps that registration across header logging and dispatch,
+   * so HMR cannot combine one adapter's capability result with another adapter.
+   * @param config - provider/model route and optional request controls.
+   * @param signal - optional cancellation for adapter-owned capability lookup.
+   * @returns a prepared config and its registration-bound stream entry point.
+   */
+  async prepareCall(config: LlmCallConfig, signal?: AbortSignal): Promise<PreparedLlmCall> {
+    const registration = this.registration(config.provider)
+    const resolvedConfig = deepFreeze(structuredClone(
+      await this.resolveCallConfigFor(registration, config, signal),
+    ))
+    let dispatched = false
+    return Object.freeze({
+      config: resolvedConfig,
+      stream: (options: GenerateOptions): AsyncIterable<StreamChunk> => {
+        if (dispatched) {
+          throw new LlmError('a prepared LLM call can only be dispatched once', 'INVALID_PREPARED_CALL')
+        }
+        dispatched = true
+        return this.streamWithRegistration(options, { registration, config: resolvedConfig })
+      },
+    })
+  }
+
+  private registration(provider: string): AdapterRegistration {
     const registration = this.adapters.get(provider)
     if (!registration) throw new LlmError(`no adapter registered for provider "${provider}"`, 'NO_ADAPTER')
     return registration
@@ -295,11 +454,27 @@ export class LlmService extends Service {
   private async * adapterStream(
     options: GenerateOptions,
     failures: AdapterFailureScope,
+    prepared?: { registration: AdapterRegistration; config: LlmCallConfig },
   ): AsyncGenerator<StreamChunk> {
     let iterator: AsyncIterator<StreamChunk>
     try {
-      const adapter = this.registration(options.provider).adapter
-      const stream = adapter.stream(this.forAdapter(options, adapter))
+      const registration = prepared?.registration ?? this.registration(options.provider)
+      const resolvedConfig = prepared === undefined
+        ? await this.resolveCallConfigFor(registration, options, options.signal)
+        : prepared.config
+      if (prepared !== undefined && !callConfigEquals(options, resolvedConfig)) {
+        throw new LlmError(
+          'prepared LLM call config changed before adapter dispatch',
+          'INVALID_PREPARED_CALL',
+        )
+      }
+      const resolvedOptions = prepared !== undefined || callConfigEquals(options, resolvedConfig)
+        ? options
+        : Object.isFrozen(options)
+          ? deepFreeze({ ...options, ...resolvedConfig })
+          : { ...options, ...resolvedConfig }
+      const adapter = registration.adapter
+      const stream = adapter.stream(this.forAdapter(resolvedOptions, adapter))
       iterator = stream[Symbol.asyncIterator]()
     } catch (error: unknown) {
       throw markLlmAdapterFailure(failures, error)
@@ -339,18 +514,36 @@ export class LlmService extends Service {
    * `LlmError` with code `NO_ADAPTER` if no adapter is registered for
    * `options.provider`. Replay state is retained only when the same adapter
    * instance owns its historical provider and the target provider. Final
-   * adapter selection, dispatch, and iteration failures retain their original
-   * Error identity and are tagged in a call-local scope for narrow agent-loop
-   * request recovery; middleware and nested-call failures remain untagged for
-   * the outer call.
+   * adapter selection remains fixed through asynchronous exact-model resolution
+   * and dispatch. Selection, dispatch, and iteration failures retain their
+   * original Error identity and are tagged in a call-local scope for narrow
+   * agent-loop request recovery; middleware and nested-call failures remain
+   * untagged for the outer call.
    * @param options - the full request; `options.provider` selects the adapter.
    * @returns the chunk stream, possibly wrapped by `llm/stream` listeners.
    */
   stream(options: GenerateOptions): AsyncIterable<StreamChunk> {
+    return this.streamWithRegistration(options)
+  }
+
+  private streamWithRegistration(
+    options: GenerateOptions,
+    prepared?: { registration: AdapterRegistration; config: LlmCallConfig },
+  ): AsyncIterable<StreamChunk> {
     const failures: AdapterFailureScope = new WeakMap<Error, LlmFailure>()
-    const stream = this.ctx.waterfall(this, 'llm/stream', options, () => this.adapterStream(options, failures))
+    const stream = this.ctx.waterfall(
+      this,
+      'llm/stream',
+      options,
+      () => this.adapterStream(options, failures, prepared),
+    )
     return bindAdapterFailureScope(stream, failures)
   }
 }
 
+interface AdapterRegistration {
+  readonly adapter: LlmAdapter
+  readonly provider: LlmProviderInfo
+}
+
 export default LlmService

packages/llm/llm/src/types.ts

@@ -5,7 +5,7 @@
  */
 
 import type { Branded } from '@deepseek-ai/dsh-brand'
-import type { CallId, ProviderRequestId } from './brand.ts'
+import type { CallId, ProviderRequestId, ReasoningEffortId } from './brand.ts'
 
 /** Serializable provider-boundary facts; policy decides whether they are retryable. */
 export interface LlmFailure {
@@ -161,6 +161,35 @@ export interface LlmModelContext {
   contextWindow: number
 }
 
+/** Display metadata for one adapter-owned reasoning effort. */
+export interface LlmReasoningEffortInfo {
+  /** Opaque stable value accepted by {@link GenerateOptions.reasoningEffort}. */
+  id: ReasoningEffortId
+  /** Human-readable effort name for selectors and diagnostics. */
+  name: string
+  /** Optional user-facing distinction from otherwise similar efforts. */
+  description?: string
+}
+
+/** Selectable reasoning efforts for one exact provider/model route. */
+export interface LlmModelReasoningInfo {
+  /** Supported efforts in adapter-preferred display order. */
+  efforts: readonly LlmReasoningEffortInfo[]
+  /**
+   * Adapter-configured default materialized into requests when callers omit
+   * an effort. Absence preserves the provider's own default.
+   */
+  defaultEffort?: ReasoningEffortId
+}
+
+/** Exact-route model metadata resolved by its owning adapter. */
+export interface LlmResolvedModelInfo extends LlmModelInfo {
+  /** Provider-owned context capacity when known. */
+  context?: LlmModelContext
+  /** Adapter-owned selectable reasoning levels when exposed. */
+  reasoning?: LlmModelReasoningInfo
+}
+
 /**
  * Raw streaming protocol emitted by adapters.
  * Block indexes correlate interleaved deltas, and `block-end` carries the
@@ -201,6 +230,8 @@ export interface GenerateOptions {
   /** Registered provider route selecting the adapter instance. */
   provider: string
   model: string
+  /** Adapter-owned reasoning effort selected for this exact model. */
+  reasoningEffort?: ReasoningEffortId
   /**
    * Ordered conversation messages, exactly as the provider sees them (after
    * the `system` slot). A loop-built request assembles them as

packages/llm/llm/tests/call-config.spec.ts

@@ -6,6 +6,7 @@
 
 import { describe, expect, it } from 'vitest'
 import { callConfigEquals, deepFreeze, isAgentLoopRequest, markAgentLoopRequest } from '../src/call-config.ts'
+import { ReasoningEffortId } from '../src/brand.ts'
 import type { GenerateOptions } from '../src/types.ts'
 
 describe('callConfigEquals', () => {
@@ -14,6 +15,11 @@ describe('callConfigEquals', () => {
     expect(callConfigEquals(base, base)).toBe(true)
     expect(callConfigEquals(base, { provider: 'x', model: 'm' })).toBe(false)
     expect(callConfigEquals(base, { provider: 'p', model: 'x' })).toBe(false)
+    expect(callConfigEquals({ ...base, reasoningEffort: ReasoningEffortId('high') }, base)).toBe(false)
+    expect(callConfigEquals(
+      { ...base, reasoningEffort: ReasoningEffortId('high') },
+      { ...base, reasoningEffort: ReasoningEffortId('high') },
+    )).toBe(true)
     expect(callConfigEquals({ ...base, temperature: 0.5 }, base)).toBe(false)
     expect(callConfigEquals({ ...base, maxTokens: 1 }, { ...base, maxTokens: 2 })).toBe(false)
     expect(callConfigEquals({ ...base, stop: ['a'] }, base)).toBe(false)

packages/llm/llm/tests/service.spec.ts

@@ -11,9 +11,16 @@ import LlmService, {
   LlmError,
   llmFailureOf,
   ProviderRequestId,
+  ReasoningEffortId,
   StreamChunk,
 } from '@deepseek-ai/dsh-llm'
-import type { LlmModelContext, LlmModelInfo, LlmProviderInfo } from '@deepseek-ai/dsh-llm'
+import type {
+  LlmModelContext,
+  LlmModelInfo,
+  LlmModelReasoningInfo,
+  LlmProviderInfo,
+  LlmResolvedModelInfo,
+} from '@deepseek-ai/dsh-llm'
 
 class ScriptedAdapter extends LlmAdapter {
   constructor(private script: StreamChunk[]) {
@@ -49,6 +56,7 @@ class CatalogAdapter extends ScriptedAdapter {
     private readonly provider: LlmProviderInfo,
     private readonly models: readonly LlmModelInfo[],
     private readonly contexts: Readonly<Record<string, LlmModelContext>> = {},
+    private readonly reasoning: Readonly<Record<string, LlmModelReasoningInfo>> = {},
   ) {
     super(SCRIPT)
   }
@@ -61,11 +69,17 @@ class CatalogAdapter extends ScriptedAdapter {
     return Promise.resolve(this.models)
   }
 
-  override resolveModelContext(
-    _provider: string,
+  override resolveModel(
+    provider: string,
     model: string,
-  ): Promise<LlmModelContext | undefined> {
-    return Promise.resolve(this.contexts[model])
+  ): Promise<LlmResolvedModelInfo> {
+    return Promise.resolve({
+      provider,
+      id: model,
+      name: model,
+      ...this.contexts[model] === undefined ? {} : { context: this.contexts[model] },
+      ...this.reasoning[model] === undefined ? {} : { reasoning: this.reasoning[model] },
+    })
   }
 }
 
@@ -739,8 +753,32 @@ describe('LlmService', () => {
     expect(ctx.llm.listProviders()).toEqual([{ id: 'plain', name: 'plain' }])
     await expect(ctx.llm.listModels('plain')).resolves.toEqual([])
     await expect(ctx.llm.listModels('missing')).rejects.toMatchObject({ code: 'NO_ADAPTER' })
-    await expect(ctx.llm.resolveModelContext('plain', 'unlisted')).resolves.toBeUndefined()
-    await expect(ctx.llm.resolveModelContext('missing', 'm')).rejects.toMatchObject({ code: 'NO_ADAPTER' })
+    await expect(ctx.llm.resolveModelInfo('plain', 'unlisted')).resolves.toEqual({
+      provider: 'plain', id: 'unlisted', name: 'unlisted',
+    })
+    await expect(ctx.llm.resolveModelInfo('missing', 'm')).rejects.toMatchObject({ code: 'NO_ADAPTER' })
+  })
+
+  it.each([
+    [{ provider: 1, id: 'model', name: 'Model' }, 'non-string provider'],
+    [{ provider: 'other', id: 'model', name: 'Model' }, 'mismatched provider'],
+    [{ provider: 'route', id: 1, name: 'Model' }, 'non-string id'],
+    [{ provider: 'route', id: 'other', name: 'Model' }, 'mismatched id'],
+    [{ provider: 'route', id: 'model', name: 1 }, 'non-string name'],
+    [{ provider: 'route', id: 'model', name: '' }, 'empty name'],
+    [{ provider: 'route', id: 'model', name: 'Model', description: 1 }, 'non-string description'],
+  ] as const)('rejects invalid exact model metadata (%s: %s)', async (metadata, _label) => {
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    const adapter = new class extends ScriptedAdapter {
+      override resolveModel(): Promise<LlmResolvedModelInfo> {
+        return Promise.resolve(metadata as unknown as LlmResolvedModelInfo)
+      }
+    }(SCRIPT)
+    ctx.llm.registerAdapter(['route'], adapter)
+
+    await expect(ctx.llm.resolveModelInfo('route', 'model'))
+      .rejects.toMatchObject({ code: 'INVALID_MODEL_INFO' })
   })
 
   it('resolves detached model context independently of advisory catalog membership', async () => {
@@ -753,11 +791,241 @@ describe('LlmService', () => {
       { unlisted: source },
     ))
 
-    const resolved = await ctx.llm.resolveModelContext('route', 'unlisted')
-    expect(resolved).toEqual({ contextWindow: 32_000 })
+    const resolved = await ctx.llm.resolveModelInfo('route', 'unlisted')
+    expect(resolved.context).toEqual({ contextWindow: 32_000 })
     source.contextWindow = 64_000
-    expect(resolved).toEqual({ contextWindow: 32_000 })
-    await expect(ctx.llm.resolveModelContext('route', 'other')).resolves.toBeUndefined()
+    expect(resolved.context).toEqual({ contextWindow: 32_000 })
+    await expect(ctx.llm.resolveModelInfo('route', 'other')).resolves.toEqual({
+      provider: 'route', id: 'other', name: 'other',
+    })
+  })
+
+  it('resolves detached adapter-owned reasoning metadata and materializes its default', async () => {
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    const source = {
+      efforts: [
+        { id: ReasoningEffortId('standard'), name: 'Standard' },
+        { id: ReasoningEffortId('ultra'), name: 'Ultra', description: 'Largest budget' },
+      ],
+      defaultEffort: ReasoningEffortId('standard'),
+    }
+    ctx.llm.registerAdapter(['route'], new CatalogAdapter(
+      { id: 'route', name: 'Route' },
+      [],
+      {},
+      { model: source },
+    ))
+
+    const resolved = await ctx.llm.resolveModelInfo('route', 'model')
+    expect(resolved.reasoning).toEqual(source)
+    source.efforts[0]!.name = 'mutated'
+    expect(resolved.reasoning?.efforts[0]?.name).toBe('Standard')
+    await expect(ctx.llm.resolveCallConfig({ provider: 'route', model: 'model' })).resolves.toEqual({
+      provider: 'route',
+      model: 'model',
+      reasoningEffort: ReasoningEffortId('standard'),
+    })
+    const explicit = { provider: 'route', model: 'model', reasoningEffort: ReasoningEffortId('ultra') }
+    await expect(ctx.llm.resolveCallConfig(explicit)).resolves.toBe(explicit)
+  })
+
+  it.each([
+    [{ efforts: [] }, 'empty effort list'],
+    [{ efforts: [{ id: '', name: 'Empty' }] }, 'empty id'],
+    [{ efforts: [{ id: 'valid', name: '' }] }, 'empty name'],
+    [{ efforts: [{ id: 'valid', name: 'Valid', description: 1 }] }, 'non-string description'],
+    [{ efforts: [{ id: 'same', name: 'One' }, { id: 'same', name: 'Two' }] }, 'duplicate id'],
+    [{ efforts: [{ id: 'valid', name: 'Valid' }], defaultEffort: 'other' }, 'unknown default'],
+  ] as const)('rejects invalid model reasoning metadata (%s: %s)', async (metadata, _label) => {
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    ctx.llm.registerAdapter(['route'], new CatalogAdapter(
+      { id: 'route', name: 'Route' },
+      [],
+      {},
+      { model: metadata as unknown as LlmModelReasoningInfo },
+    ))
+    await expect(ctx.llm.resolveModelInfo('route', 'model'))
+      .rejects.toMatchObject({ code: 'INVALID_MODEL_REASONING' })
+  })
+
+  it('rejects unsupported reasoning efforts without clamping', async () => {
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    ctx.llm.registerAdapter(['route'], new CatalogAdapter(
+      { id: 'route', name: 'Route' },
+      [],
+      {},
+      { model: { efforts: [{ id: ReasoningEffortId('ultra'), name: 'Ultra' }] } },
+    ))
+
+    await expect(ctx.llm.resolveCallConfig({
+      provider: 'route',
+      model: 'model',
+      reasoningEffort: ReasoningEffortId('standard'),
+    })).rejects.toMatchObject({ code: 'UNSUPPORTED_REASONING_EFFORT' })
+    await expect(ctx.llm.resolveCallConfig({
+      provider: 'route',
+      model: 'plain',
+      reasoningEffort: ReasoningEffortId('standard'),
+    })).rejects.toMatchObject({ code: 'UNSUPPORTED_REASONING_EFFORT' })
+  })
+
+  it('resolves reasoning defaults at the final adapter boundary after routing middleware', async () => {
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    const adapter = new class extends RecordingAdapter {
+      override resolveModel(provider: string, model: string): Promise<LlmResolvedModelInfo> {
+        const reasoning: LlmModelReasoningInfo = {
+          efforts: [{ id: ReasoningEffortId('standard'), name: 'Standard' }],
+          defaultEffort: ReasoningEffortId('standard'),
+        }
+        return Promise.resolve({
+          provider,
+          id: model,
+          name: model,
+          reasoning,
+        })
+      }
+    }(SCRIPT)
+    ctx.llm.registerAdapter(['routed'], adapter)
+    const disposeRouting = ctx.on('llm/stream', (options, next) => {
+      options.provider = 'routed'
+      return next()
+    })
+
+    for await (const _chunk of ctx.llm.stream({
+      provider: 'initial',
+      model: 'model',
+      messages: [],
+    })) { /* drain */ }
+
+    expect(adapter.lastOptions?.reasoningEffort).toBe(ReasoningEffortId('standard'))
+    disposeRouting()
+
+    const frozenRequest: GenerateOptions = Object.freeze({
+      provider: 'routed',
+      model: 'model',
+      messages: [],
+    })
+    for await (const _chunk of ctx.llm.stream(frozenRequest)) { /* drain */ }
+    expect(adapter.lastOptions?.reasoningEffort).toBe(ReasoningEffortId('standard'))
+    expect(Object.isFrozen(adapter.lastOptions)).toBe(true)
+  })
+
+  it('pins one adapter registration across asynchronous exact-model resolution and dispatch', async () => {
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    const started = Promise.withResolvers<undefined>()
+    const reasoning = Promise.withResolvers<LlmModelReasoningInfo>()
+    const first = new class extends RecordingAdapter {
+      override async resolveModel(
+        provider: string,
+        model: string,
+        _signal?: AbortSignal,
+      ): Promise<LlmResolvedModelInfo> {
+        started.resolve(undefined)
+        return {
+          provider,
+          id: model,
+          name: model,
+          reasoning: await reasoning.promise,
+        }
+      }
+    }(SCRIPT)
+    const disposeFirst = ctx.llm.registerAdapter(['route'], first)
+    const draining = (async () => {
+      for await (const _chunk of ctx.llm.stream({
+        provider: 'route',
+        model: 'model',
+        messages: [],
+      })) { /* drain */ }
+    })()
+
+    await started.promise
+    disposeFirst()
+    const second = new RecordingAdapter(SCRIPT)
+    ctx.llm.registerAdapter(['route'], second)
+    reasoning.resolve({
+      efforts: [{ id: ReasoningEffortId('high'), name: 'High' }],
+      defaultEffort: ReasoningEffortId('high'),
+    })
+    await draining
+
+    expect(first.lastOptions?.reasoningEffort).toBe(ReasoningEffortId('high'))
+    expect(second.lastOptions).toBeUndefined()
+  })
+
+  it('prepares a one-shot registration-bound call and rejects config drift', async () => {
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    const adapter = new CatalogAdapter(
+      { id: 'route', name: 'Route' },
+      [],
+      {},
+      {
+        model: {
+          efforts: [{ id: ReasoningEffortId('high'), name: 'High' }],
+          defaultEffort: ReasoningEffortId('high'),
+        },
+      },
+    )
+    ctx.llm.registerAdapter(['route'], adapter)
+    const prepared = await ctx.llm.prepareCall({ provider: 'route', model: 'model' })
+    expect(Object.isFrozen(prepared.config)).toBe(true)
+    const stream = prepared.stream({
+      ...prepared.config,
+      model: 'other',
+      messages: [],
+    })
+
+    await expect((async () => {
+      for await (const _chunk of stream) { /* drain */ }
+    })()).rejects.toMatchObject({ code: 'INVALID_PREPARED_CALL' })
+    expect(() => prepared.stream({
+      ...prepared.config,
+      messages: [],
+    })).toThrow(expect.objectContaining({ code: 'INVALID_PREPARED_CALL' }))
+  })
+
+  it('passes cancellation through exact-model resolution', async () => {
+    const ctx = new Context()
+    await ctx.plugin(LlmService)
+    const started = Promise.withResolvers<undefined>()
+    const adapter = new class extends ScriptedAdapter {
+      override resolveModel(
+        _provider: string,
+        _model: string,
+        signal?: AbortSignal,
+      ): Promise<LlmResolvedModelInfo> {
+        started.resolve(undefined)
+        return new Promise<LlmResolvedModelInfo>((_resolve, reject) => {
+          if (signal === undefined) {
+            reject(new Error('missing reasoning signal'))
+            return
+          }
+          if (signal.aborted) {
+            reject(signal.reason instanceof Error ? signal.reason : new Error('reasoning aborted'))
+            return
+          }
+          signal.addEventListener('abort', () => {
+            reject(signal.reason instanceof Error ? signal.reason : new Error('reasoning aborted'))
+          }, { once: true })
+        })
+      }
+    }(SCRIPT)
+    ctx.llm.registerAdapter(['route'], adapter)
+    const controller = new AbortController()
+    const resolving = ctx.llm.resolveCallConfig(
+      { provider: 'route', model: 'model' },
+      controller.signal,
+    )
+
+    await started.promise
+    const reason = new Error('cancel reasoning')
+    controller.abort(reason)
+    await expect(resolving).rejects.toBe(reason)
   })
 
   it.each([0, -1, 1.5, Number.NaN])(
@@ -770,7 +1038,7 @@ describe('LlmService', () => {
         [],
         { model: { contextWindow } },
       ))
-      await expect(ctx.llm.resolveModelContext('route', 'model'))
+      await expect(ctx.llm.resolveModelInfo('route', 'model'))
         .rejects.toMatchObject({ code: 'INVALID_MODEL_CONTEXT' })
     },
   )