feat(apiproxy): session.rename RPC delegating to the session-title service

New unary method in RpcMethodMap with the title-invalid error code; the impl
resolves the agent (cold sessions resume first) and delegates to
ctx.sessionTitle.rename, returning the normalized title plus its event seq so
clients settle the title projection cell ahead of the push frame. session.fork
stays on the reserved-seam list.

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: ca4471454f5be5d3fcba38ce665d4fb3fbd85e74
-README.zh.md: 953539e1198a52b2bf7cdd9ca1b0d263cc2ae6f9
+README.md: b5f80dcb3a077a411db3b721737a9c16b56fcecf
+README.zh.md: 1c3c7486f7d500f8c2d36028d47f29b112d9b5ae

packages/host/apiproxy/README.md

@@ -12,7 +12,7 @@ The layering/protocol decisions are recorded in the [GUI layering and RPC protoc
 
 `session.history`'s tail page (`beforeSeq` absent) additionally carries an optional `projections` block — the watermark snapshot of every unit registered on `ctx.sessionProjections` (`@deepseek-ai/dsh-session-projection`), with `asOfSeq` = the last event seq the values reflect (`-1` on an empty log). The gateway also subscribes to the registry's change feed and mints a `session/projection` mux frame per changed unit (`{sessionId, key, value, seq}` — live push state, never logged; clients hold one generic per-session value store under higher-seq-wins). The carrier holds zero domain knowledge (each value passed its unit's own schema inside the registry; the wire schemas keep `values`/`value` wide); loadOlder pages never carry the block, and a composition without the registry serves histories without either surface.
 
-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 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 model routing is a session-domain contract. `session.models` returns the selected provider/model/reasoning target with provider-grouped advisory models, exact-route reasoning metadata, and provider-local lookup failures. `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`.
 

packages/host/apiproxy/README.zh.md

@@ -12,7 +12,7 @@
 
 `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铸造一个 `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。
+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`。
 
 会话模型路由属于会话领域契约。`session.models` 返回选中的提供方／模型／推理（reasoning）目标，以及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。`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`。
 

packages/host/apiproxy/package.json

@@ -51,6 +51,7 @@
     "@deepseek-ai/dsh-session-persistence": "workspace:^",
     "@deepseek-ai/dsh-session-projection": "workspace:^",
     "@deepseek-ai/dsh-session-projection-cache": "workspace:^",
+    "@deepseek-ai/dsh-session-title": "workspace:^",
     "@deepseek-ai/dsh-skill": "workspace:^",
     "@deepseek-ai/dsh-tools": "workspace:^",
     "@deepseek-ai/dsh-user-approval": "workspace:^",

packages/host/apiproxy/src/api-proxy.ts

@@ -36,6 +36,8 @@ import type {} from '@deepseek-ai/dsh-session-projection-cache'
 import { GoalError } from '@deepseek-ai/dsh-goal'
 import type { GoalRef as CoreGoalRef } from '@deepseek-ai/dsh-goal'
 // Type-only edges: resolve `ctx.get('commands')`, the `commands/change` event, and `ctx.get('skills')`.
+// Type-only edge: resolves `ctx.get('sessionTitle')` for the rename impl.
+import type {} from '@deepseek-ai/dsh-session-title'
 import type {} from '@deepseek-ai/dsh-commands'
 import type {} from '@deepseek-ai/dsh-skill'
 import type { CallId } from '@deepseek-ai/dsh-llm/brand'
@@ -1049,6 +1051,26 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
         }
       },
 
+      async rename(request) {
+        const { sessionId, title } = request.payload
+        const found = await agentFor(sessionId)
+        if ('error' in found) return err(request, found.error)
+        const titles = ctx.get('sessionTitle')
+        if (titles === undefined) {
+          return err(request, { code: 'internal', message: 'session-title service is absent: this deployment does not mount @deepseek-ai/dsh-session-title in its composition (cordis.yml or explicit assembly)', details: {} })
+        }
+        try {
+          const accepted = titles.rename(found.agent.session, title)
+          return ok(request, { title: accepted.title, seq: accepted.eventSeq })
+        } catch (error: unknown) {
+          return err(request, {
+            code: 'title-invalid',
+            message: `rename rejected for session "${sessionId}": ${String(error)}`,
+            details: { sessionId },
+          })
+        }
+      },
+
       async prompt(request) {
         const { sessionId, mode, content } = request.payload
         const found = await agentFor(sessionId)

packages/host/apiproxy/src/api/rpc-map.ts

@@ -23,6 +23,7 @@ export interface RpcMethodMap {
   'session.history': SessionsApi['history']
   'session.models': SessionsApi['models']
   'session.selectModel': SessionsApi['selectModel']
+  'session.rename': SessionsApi['rename']
   'session.prompt': SessionsApi['prompt']
   'session.cancel': SessionsApi['cancel']
   'host.describe': HostApi['describe']

packages/host/apiproxy/src/api/rpc.schema.ts

@@ -49,6 +49,7 @@ export const rpcErrorSchema: z.ZodType<RpcError> = z.discriminatedUnion('code',
   z.object({ code: z.literal('agent-busy'), message: z.string(), details: z.object({ reason: z.string() }) }),
   z.object({ code: z.literal('command-error'), message: z.string(), details: z.object({}) }),
   z.object({ code: z.literal('unknown-command'), message: z.string(), details: z.object({}) }),
+  z.object({ code: z.literal('title-invalid'), message: z.string(), details: z.object({ sessionId: z.string() }) }),
   z.object({ code: z.literal('internal'), message: z.string(), details: z.object({}) }),
 ]) as unknown as z.ZodType<RpcError>
 

packages/host/apiproxy/src/api/rpc.ts

@@ -48,6 +48,7 @@ export interface RpcErrorDetailsMap {
   'command-error': {}
   /** A leading-/ prompt named no registered command; the message names the token. */
   'unknown-command': {}
+  'title-invalid': { sessionId: SessionId }
   'internal': {}
 }
 

packages/host/apiproxy/src/api/sessions.schema.ts

@@ -73,6 +73,18 @@ export const sessionCreateValueSchema = z.object({
   sessionId: sessionIdSchema,
 }) satisfies z.ZodType<Wire<ResponseValue<'session.create'>>>
 
+/** session.rename request payload (raw title; host-side normalization decides acceptance). */
+export const sessionRenameRequestSchema = z.object({
+  sessionId: sessionIdSchema,
+  title: z.string(),
+}) satisfies z.ZodType<Wire<RequestPayload<'session.rename'>>>
+
+/** session.rename response value (the normalized accepted title and its event seq). */
+export const sessionRenameValueSchema = z.object({
+  title: z.string().min(1),
+  seq: z.number().int().nonnegative(),
+}) satisfies z.ZodType<Wire<ResponseValue<'session.rename'>>>
+
 /** session.history request payload (beforeSeq/maxMessages page backwards from the window tail). */
 export const sessionHistoryRequestSchema = z.object({
   sessionId: sessionIdSchema,

packages/host/apiproxy/src/api/sessions.ts

@@ -208,6 +208,16 @@ export interface SessionsApi {
   }>):
   Promise<RpcResponse<{ selected: ModelTarget }>>
 
+  /**
+   * Renames a session: appends a `session/title` event with the `user`
+   * source, which pins the title against automatic regeneration. The
+   * normalized accepted title and the title event's seq return so the caller
+   * can settle its projection cell without waiting for the push frame. A
+   * title that normalizes to empty fails with `title-invalid`.
+   */
+  rename(request: RpcRequest<{ sessionId: SessionId; title: string }>):
+  Promise<RpcResponse<{ title: string; seq: number }>>
+
   /**
    * Sends a message. content is core's ContentBlock[] verbatim; mode maps 1:1 — queue→send, steer→steer.
    * A prompt whose content is exactly one text block starting with '/' is a slash command: the host

packages/host/apiproxy/src/fetch/client.ts

@@ -20,6 +20,7 @@ import {
 import {
   sessionCancelValueSchema,
   sessionCreateValueSchema,
+  sessionRenameValueSchema,
   sessionHistoryValueSchema,
   sessionListValueSchema,
   sessionModelsValueSchema,
@@ -66,6 +67,7 @@ export interface IApiClient {
     history(payload: RequestPayload<'session.history'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.history'>>>
     models(payload: RequestPayload<'session.models'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.models'>>>
     selectModel(payload: RequestPayload<'session.selectModel'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.selectModel'>>>
+    rename(payload: RequestPayload<'session.rename'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.rename'>>>
     prompt(payload: RequestPayload<'session.prompt'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.prompt'>>>
     cancel(payload: RequestPayload<'session.cancel'>, signal?: AbortSignal): Promise<RpcResponse<ResponseValue<'session.cancel'>>>
   }
@@ -116,6 +118,7 @@ const UNARY_VALUE_SCHEMAS: { [K in keyof RpcMethodMap]: z.ZodType<Wire<ResponseV
   'session.history': sessionHistoryValueSchema,
   'session.models': sessionModelsValueSchema,
   'session.selectModel': sessionSelectModelValueSchema,
+  'session.rename': sessionRenameValueSchema,
   'session.prompt': sessionPromptValueSchema,
   'session.cancel': sessionCancelValueSchema,
   'host.describe': hostDescribeValueSchema,
@@ -327,6 +330,7 @@ export abstract class AbstractApiClient implements IApiClient {
     history: (payload, signal) => this.callUnary('session.history', payload, signal),
     models: (payload, signal) => this.callUnary('session.models', payload, signal),
     selectModel: (payload, signal) => this.callUnary('session.selectModel', payload, signal),
+    rename: (payload, signal) => this.callUnary('session.rename', payload, signal),
     prompt: (payload, signal) => this.callUnary('session.prompt', payload, signal),
     cancel: (payload, signal) => this.callUnary('session.cancel', payload, signal),
   }

packages/host/apiproxy/src/fetch/handler.ts

@@ -17,6 +17,7 @@ import { clientRequestSchema, clientResponseSchema } from '../api/rpc.schema.ts'
 import {
   sessionCancelRequestSchema,
   sessionCreateRequestSchema,
+  sessionRenameRequestSchema,
   sessionHistoryRequestSchema,
   sessionListRequestSchema,
   sessionModelsRequestSchema,
@@ -68,6 +69,7 @@ const UNARY_ROUTES: UnaryRoutes = {
   'session.history': { schema: sessionHistoryRequestSchema, invoke: (api, r) => api.sessions.history(r) },
   'session.models': { schema: sessionModelsRequestSchema, invoke: (api, r) => api.sessions.models(r) },
   'session.selectModel': { schema: sessionSelectModelRequestSchema, invoke: (api, r) => api.sessions.selectModel(r) },
+  'session.rename': { schema: sessionRenameRequestSchema, invoke: (api, r) => api.sessions.rename(r) },
   'session.prompt': { schema: sessionPromptRequestSchema, invoke: (api, r) => api.sessions.prompt(r) },
   'session.cancel': { schema: sessionCancelRequestSchema, invoke: (api, r) => api.sessions.cancel(r) },
   'host.describe': { schema: hostDescribeRequestSchema, invoke: (api, r) => api.host.describe(r) },

packages/host/apiproxy/tests/api-proxy-rename.spec.ts

@@ -0,0 +1,110 @@
+/**
+ * sessions.rename delegation through the composed SessionTitleService. The
+ * agent factory is a structural stub whose createAgent forwards seed/meta into
+ * the real SessionStore, and whose resume never runs (every source here is
+ * already attached).
+ */
+
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import SessionStore from '@deepseek-ai/dsh-session'
+import AgentRegistry from '@deepseek-ai/dsh-agent'
+import type { Agent, AgentHandle, CreateAgentOptions } from '@deepseek-ai/dsh-agent'
+import { createUserMessage } from '@deepseek-ai/dsh-llm'
+import SessionTitleService from '@deepseek-ai/dsh-session-title'
+import UserInteractionService from '@deepseek-ai/dsh-user-interaction'
+import type { Session, SessionId } from '@deepseek-ai/dsh-session'
+import type { RpcRequest } from '@deepseek-ai/dsh-host-apiproxy/api/rpc'
+import { RpcId } from '@deepseek-ai/dsh-host-apiproxy/api/rpc'
+import { createApiProxy } from '@deepseek-ai/dsh-host-apiproxy'
+
+const sid = (id: string): SessionId => id as SessionId
+
+let nextRpc = 1
+function request<P>(payload: P): RpcRequest<P> {
+  return { rpcId: RpcId(`fr-${String(nextRpc++)}`), payload }
+}
+
+async function composed(withTitles = true): Promise<Context> {
+  const ctx = new Context()
+  await ctx.plugin(SessionStore)
+  await ctx.plugin(AgentRegistry)
+  await ctx.plugin(UserInteractionService)
+  if (withTitles) {
+    await ctx.plugin(SessionTitleService, { fallbackMaxWords: 5, fallbackMaxBytes: 40, maxTitleBytes: 40 })
+  }
+  // Store-backed structural factory: create builds the session with the
+  // forwarded seed/meta (the store validates the balanced prefix) and
+  // registers an idle agent stub over it.
+  ctx.agents.setFactory({
+    createAgent: (ownerCtx: Context, options: CreateAgentOptions): Promise<AgentHandle> => {
+      const session = ctx.sessions.create(options.sessionId, {
+        ...options.seed === undefined ? {} : { seed: [...options.seed] },
+        ...options.meta === undefined ? {} : { meta: options.meta },
+      })
+      const agent = { id: session.id, session, status: 'idle', ctx: ownerCtx } as Agent
+      ctx.agents.register(agent)
+      return Promise.resolve({ agent, dispose: () => Promise.resolve() })
+    },
+    resume: () => Promise.reject(new Error('resume must not run: every source is attached')),
+  })
+  return ctx
+}
+
+/** Register one live agent whose log holds `turns` completed turns. */
+function liveAgent(ctx: Context, id: string, turns: number): Session {
+  const session = ctx.sessions.create(sid(id), { meta: { cwd: '/proj' } })
+  for (let turn = 1; turn <= turns; turn++) {
+    session.append('turn/start', { turn, trigger: { kind: 'message', source: { kind: 'user' } } })
+    session.append('user/message', createUserMessage({
+      content: [{ type: 'text', text: `prompt ${String(turn)}` }],
+      source: { kind: 'user' },
+    }), { surfaceOp: 'append' })
+    session.append('turn/end', { turn, reason: { kind: 'completed' } })
+  }
+  ctx.agents.register({ id: session.id, session, status: 'idle', ctx } as Agent)
+  return session
+}
+
+const api = (ctx: Context) => createApiProxy(ctx, { 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 () => {
+    const ctx = await composed()
+    const source = liveAgent(ctx, 'session-rename', 1)
+
+    const renamed = await api(ctx).sessions.rename(request({ sessionId: source.id, title: '  new   name  ' }))
+    expect(renamed.result.ok).toBe(true)
+    if (!renamed.result.ok) return
+    expect(renamed.result.value.title).toBe('new name')
+    const event = source.events.findLast(item => item.type === 'session/title')
+    expect(event?.seq).toBe(renamed.result.value.seq)
+    expect(event?.data).toMatchObject({ title: 'new name', source: { kind: 'user' } })
+  })
+
+  it('maps an empty-normalizing title to title-invalid', async () => {
+    const ctx = await composed()
+    const source = liveAgent(ctx, 'session-rename-bad', 1)
+
+    const response = await api(ctx).sessions.rename(request({ sessionId: source.id, title: '   ' }))
+    expect(response.result.ok).toBe(false)
+    if (!response.result.ok) {
+      expect(response.result.error).toMatchObject({
+        code: 'title-invalid',
+        details: { sessionId: source.id },
+      })
+    }
+  })
+
+  it('answers internal when the composition mounts no session-title service', async () => {
+    const ctx = await composed(false)
+    const source = liveAgent(ctx, 'session-no-titles', 1)
+
+    const response = await api(ctx).sessions.rename(request({ sessionId: source.id, title: 'name' }))
+    expect(response.result.ok).toBe(false)
+    if (!response.result.ok) {
+      expect(response.result.error.code).toBe('internal')
+      expect(response.result.error.message).toMatch(/session-title service is absent/)
+    }
+  })
+})

packages/host/apiproxy/tests/client-handler.spec.ts

@@ -46,6 +46,7 @@ function scriptedApi(overrides: {
       selectModel: r => ok(r, {
         selected: { provider: r.payload.provider, model: r.payload.model },
       }),
+      rename: r => ok(r, { title: 'renamed', seq: 0 }),
       prompt: r => ok(r, { accepted: true as const }),
       cancel: r => ok(r, { accepted: true as const }),
       ...overrides.sessions,

packages/host/apiproxy/tests/fetch-carrier.spec.ts

@@ -67,6 +67,9 @@ function fakeApi(overrides: Partial<{ muxFrames: MuxFrame[]; hostFrames: HostFra
           },
         }
       },
+      async rename(request) {
+        return { rpcId: request.rpcId, result: { ok: true, value: { title: request.payload.title, seq: 0 } } }
+      },
       async prompt(request) {
         return { rpcId: request.rpcId, result: { ok: true, value: { accepted: true as const } } }
       },
@@ -224,6 +227,8 @@ describe('unary round trip (handler ⇄ client, no network)', () => {
         },
       },
     })
+    const renamed = await c.sessions.rename({ sessionId: 's' as never, title: 'named' })
+    expect(renamed.result).toMatchObject({ ok: true, value: { title: 'named', seq: 0 } })
     expect((await c.sessions.prompt({ sessionId: 's' as never, mode: 'queue', content: [{ type: 'text', text: 'x' }] })).result.ok).toBe(true)
     expect((await c.sessions.cancel({ sessionId: 's' as never })).result.ok).toBe(true)
     expect((await c.host.describe({})).result.ok).toBe(true)

packages/host/apiproxy/tsconfig.json

@@ -38,6 +38,9 @@
     {
       "path": "../../session-projection/session-projection"
     },
+    {
+      "path": "../../session-title/session-title"
+    },
     {
       "path": "../../session-projection/session-projection-cache"
     },