Merge origin/master into worktree/explicit-turn-signal

packages/subagent/subagent-inprocess/README.md

@@ -8,7 +8,7 @@ This package is the shared run driver for the two in-process providers. Spawn pa
 
 The driver follows this sequence:
 
-1. Validate the parent depth and optional absolute `maxDepth`, then derive child depth as parent depth plus one.
+1. Validate the parent depth and optional absolute `maxDepth`, then derive child depth as parent depth plus one and persist it in the child session header.
 2. Call `parent.ctx.agents.create` directly, passing the required request signal into the factory's creation transaction.
 3. During that transaction's unpublished setup window, install the requested persona, tool restriction, and structured-output runtime.
 4. Publish the child, retain the returned `AgentHandle`, and drive one task with `child.send(prompt)` followed by `child.whenIdle()`.
@@ -26,7 +26,7 @@ After fulfillment, the caller owns the run. Provider-plugin unload does not revo
 
 `InProcessRunOptions` is `{ seed?: SessionEvent[] }`. Spawn omits it. Fork supplies a balanced completed-turn prefix and records its length so the result reader never mistakes a seeded parent message for child output.
 
-`depthOf(agent)` reads `AgentOptions.subagentDepth`, treating absence as top-level depth zero and rejecting malformed stored values. `SubagentDepthError` reports an attempted child depth above `maxDepth`; an unrepresentable depth above the safe-integer domain is a `RangeError`.
+Depth enforcement is internal to `startInProcessRun`: it reads the parent depth via `delegationDepthOf` (the persisted `SessionHeader.delegationDepth` is authoritative; runtime `AgentOptions.subagentDepth` may deepen but never lower it, so a resumed child keeps its budget), treats absence as top-level depth zero, rejects malformed stored values, and reports an attempted child depth above `maxDepth`. An unrepresentable depth above the safe-integer domain is a `RangeError`. The child depth is written to the child header, so it survives persistence and resume.
 
 ## Structured output
 
@@ -44,33 +44,65 @@ A clean turn that never commits the required structured value reports `error`; t
 
 ### Child-agent request
 
-**What the model sees**: The shared driver sends the task verbatim as the child's user message and, when requested, shadows the persona and restricts global tool schemas, lookup, execution, and Code Mode SDK bindings in the unpublished child's fresh scope; parent restrictions are not inherited, and standalone tool-guidance sections remain. Spawn supplies no history; fork supplies its balanced seed.
+#### What the model sees
 
-**Token effect**: Child input is isolated from the parent and grows through the child's own steps. A persona changes repeated prompt text; filtering changes schema or generated SDK cost but not independently registered guidance.
+The shared driver sends the task verbatim as the child's user message and, when requested, shadows the persona and restricts global tool schemas, lookup, execution, and Code Mode SDK bindings in the unpublished child's fresh scope; parent restrictions are not inherited, and standalone tool-guidance sections remain. Spawn supplies no history; fork supplies its balanced seed.
+
+#### Token effect
+
+Child input is isolated from the parent and grows through the child's own steps. A persona changes repeated prompt text; filtering changes schema or generated SDK cost but not independently registered guidance.
+
+#### KV Cache effect
+
+Independent of the parent request cache. The child's later history is append-only, while persona, tool-filter, generated-SDK, provider, or model changes establish a different child prefix.
 
 ### Structured-output system prompt, schema, and results
 
-**What the model sees**: A structured run adds the structured-output instruction below. It also adds a child-scoped `structured_output` definition with exact description `Report your final structured result. Call this exactly once, when your answer is complete; the arguments must match this tool's parameter schema exactly.` and the requested schema. This runtime-only definition is outside the generated shipped [tool package map](../../../docs/tool-catalog.md#tool-package-map). Success returns `Structured output recorded.`; a later call becomes ``Error: structured output already recorded: the run is complete, so `<tool>` is not executed``.
+#### What the model sees
 
-**Token effect**: Fixed instruction and capability tokens are paid only by that child. Result text enters the child history, while the captured value alone becomes the parent result.
+A structured run adds the structured-output instruction below. It also adds a child-scoped `structured_output` definition with exact description `Report your final structured result. Call this exactly once, when your answer is complete; the arguments must match this tool's parameter schema exactly.` and the requested schema. This runtime-only definition is outside the generated shipped [tool package map](../../../docs/tool-catalog.md#tool-package-map). Success returns `Structured output recorded.`; a later call becomes ``Error: structured output already recorded: the run is complete, so `<tool>` is not executed``.
 
-#### Structured-output instruction
+##### Structured-output instruction
 
 ```markdown
 When you have your final answer, you MUST report it by calling the `structured_output` tool with arguments matching its parameter schema exactly. Do not finish with a plain text answer: only the tool call counts as your result.
 ```
 
+#### Token effect
+
+Fixed instruction and capability tokens are paid only by that child. Result text enters the child history, while the captured value alone becomes the parent result.
+
+#### KV Cache effect
+
+Prefix-stable inside the child while the structured-output instruction and schema are unchanged. Changing the schema or capability may invalidate the child's cache from that early segment; results append in child and parent histories.
+
 ### Parent start error, indirectly
 
-**What the model sees**: Through `dsh-tool-subagent`, invalid depth state becomes exactly `Error: agent subagentDepth must be a non-negative safe integer`, `Error: subagent child depth exceeds the safe-integer range`, or `Error: subagent depth <attempted> exceeds maxDepth <max>`. A pre-publication cancellation passes its abort reason through the registry's `Error: <message>` wrapper.
+#### What the model sees
 
-**Token effect**: Zero tokens on a successful start; only the failed parent tool call retains this text.
+Through `dsh-tool-subagent`, invalid depth state becomes exactly `Error: agent subagentDepth must be a non-negative safe integer`, `Error: subagent child depth exceeds the safe-integer range`, or `Error: subagent depth <attempted> exceeds maxDepth <max>`. A pre-publication cancellation passes its abort reason through the registry's `Error: <message>` wrapper.
+
+#### Token effect
+
+Zero tokens on a successful start; only the failed parent tool call retains this text.
+
+#### KV Cache effect
+
+Append-only; newly visible content follows the reusable request prefix and does not invalidate existing KV-cache entries.
 
 ### Parent result, indirectly
 
-**What the model sees**: The driver extracts only the child's own last assistant output or captured structured value; seeded parent messages and intermediate child work do not become the result.
+#### What the model sees
 
-**Token effect**: The parent receives one data-dependent result through the consumer; all other child tokens stay in the child session.
+The driver extracts only the child's own last assistant output or captured structured value; seeded parent messages and intermediate child work do not become the result.
+
+#### Token effect
+
+The parent receives one data-dependent result through the consumer; all other child tokens stay in the child session.
+
+#### KV Cache effect
+
+Append-only; newly visible content follows the reusable request prefix and does not invalidate existing KV-cache entries.
 
 ## Known Limitations and Deferred Work
 

packages/subagent/subagent-inprocess/src/index.ts

@@ -9,10 +9,10 @@
 
 import { randomUUID } from 'node:crypto'
 import type { Context } from 'cordis'
-import { AgentId, type Agent, type AgentOptions } from '@deepseek-ai/dsh-agent'
+import type { Agent, AgentOptions } from '@deepseek-ai/dsh-agent'
 import { SessionId, type SessionEvent, type TurnEndReason } from '@deepseek-ai/dsh-session'
 import type { ContentBlock } from '@deepseek-ai/dsh-llm'
-import { assertSubagentMaxDepth } from '@deepseek-ai/dsh-subagent'
+import { assertSubagentMaxDepth, delegationDepthOf } from '@deepseek-ai/dsh-subagent'
 import type { SubagentResult, SubagentRun, SubagentStartRequest, SubagentStopReason } from '@deepseek-ai/dsh-subagent'
 import {
   attachStructuredRuntime,
@@ -24,29 +24,8 @@ export {
   STRUCTURED_OUTPUT_INSTRUCTION,
 } from './structured.ts'
 
-declare module '@deepseek-ai/dsh-agent' {
-  interface AgentOptions {
-    /** Delegation depth: zero for a top-level agent and parent depth + 1 for a child. */
-    subagentDepth?: number
-  }
-}
-
-/**
- * Read an agent's delegation depth, treating absence as top-level depth zero.
- * @param agent - the agent whose options carry the depth.
- * @returns its non-negative safe-integer depth.
- */
-export function depthOf(agent: Agent): number {
-  const depth = agent.options.subagentDepth
-  if (depth === undefined) return 0
-  if (!Number.isSafeInteger(depth) || depth < 0 || Object.is(depth, -0)) {
-    throw new TypeError('agent subagentDepth must be a non-negative safe integer')
-  }
-  return depth
-}
-
 /** Thrown when starting a child would exceed the requested depth cap. */
-export class SubagentDepthError extends Error {
+class SubagentDepthError extends Error {
   constructor(public readonly attemptedDepth: number, public readonly maxDepth: number) {
     super(`subagent depth ${attemptedDepth} exceeds maxDepth ${maxDepth}`)
     this.name = 'SubagentDepthError'
@@ -96,7 +75,7 @@ export async function startInProcessRun(
   assertSubagentMaxDepth(request.maxDepth)
   if (request.signal.aborted) throw prePublicationAbort()
   const parent = request.parent
-  const childDepth = depthOf(parent) + 1
+  const childDepth = delegationDepthOf(parent) + 1
   if (!Number.isSafeInteger(childDepth)) {
     throw new RangeError('subagent child depth exceeds the safe-integer range')
   }
@@ -104,7 +83,7 @@ export async function startInProcessRun(
     throw new SubagentDepthError(childDepth, request.maxDepth)
   }
 
-  const childId = AgentId(randomUUID())
+  const childId = SessionId(randomUUID())
   const seedLength = options.seed?.length ?? 0
   const parentHeader = parent.session.header
   const parentProvider = parent.options.provider
@@ -129,11 +108,12 @@ export async function startInProcessRun(
 
   const flags = { cancelled: false }
   const handle = await parent.ctx.agents.create({
-    agentId: childId,
-    sessionId: SessionId(randomUUID()),
+    sessionId: childId,
     meta: {
       ...parentHeader.cwd !== undefined ? { cwd: parentHeader.cwd } : {},
       parentSession: parentHeader.id,
+      // Durable: the recursion budget must survive persistence and resume.
+      delegationDepth: childDepth,
       ...seedLength > 0 ? { seedLength } : {},
     },
     ...options.seed !== undefined ? { seed: options.seed } : {},
@@ -176,6 +156,7 @@ export async function startInProcessRun(
 
   return {
     id: childId,
+    localAgent: child,
     result,
     dispose(): Promise<void> {
       request.signal.removeEventListener('abort', onAbort)

packages/subagent/subagent-inprocess/tests/structured.spec.ts

@@ -1,8 +1,8 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
 import { CallId, type ContentBlock, type GenerateOptions } from '@deepseek-ai/dsh-llm'
-import { AgentId } from '@deepseek-ai/dsh-agent'
 import type { ContinuationDecision } from '@deepseek-ai/dsh-agent'
+import { SessionId } from '@deepseek-ai/dsh-session'
 import AgentLoop from '@deepseek-ai/dsh-agent-loop'
 import { mountAgentLoopTestDependencies } from '@deepseek-ai/dsh-agent-loop-testkit'
 import * as Invariants from '@deepseek-ai/dsh-invariants'
@@ -61,7 +61,7 @@ async function setup(script: Script, options: SetupOptions = {}) {
     start: (request: SubagentStartRequest) => startInProcessRun(request, {}),
   })
   ctx.llm.registerAdapter(['mock'], adapter)
-  const parent = ctx.agentLoop.create(AgentId('parent'), { provider: 'mock', model: 'mock' })
+  const parent = ctx.agentLoop.create(SessionId('parent'), { provider: 'mock', model: 'mock' })
   return { ctx, parent, adapter, disposeProvider }
 }
 
@@ -322,7 +322,7 @@ describe('in-process structured output', () => {
     await expect(ctx.subagents.start('spawn', structuredRequest(parent, {
       outputSchema: { type: 'object', oneOf: [] } as unknown as StructuredOutputSchema,
     }))).rejects.toThrow(/unsupported output schema/)
-    expect(ctx.agents.get(AgentId('parent'))).toBeDefined()
+    expect(ctx.agents.get(SessionId('parent'))).toBeDefined()
   })
 
   it('a schema carrying non-JSON values fails as OutputSchemaError at the validation boundary', async () => {

packages/subagent/subagent-inprocess/tests/subagent-inprocess.spec.ts

@@ -1,12 +1,13 @@
 import { describe, expect, it } from 'vitest'
 import { Context } from 'cordis'
-import { AgentId, type Agent } from '@deepseek-ai/dsh-agent'
+import { type Agent } from '@deepseek-ai/dsh-agent'
+import { SessionId } from '@deepseek-ai/dsh-session'
 import AgentLoop from '@deepseek-ai/dsh-agent-loop'
 import { mountAgentLoopTestDependencies } from '@deepseek-ai/dsh-agent-loop-testkit'
 import * as Invariants from '@deepseek-ai/dsh-invariants'
 import SubagentService from '@deepseek-ai/dsh-subagent'
 import { MockAdapter, textResponse } from '../../../core/agent-loop/tests/mock-adapter.ts'
-import { depthOf, SubagentDepthError, startInProcessRun } from '../src/index.ts'
+import { startInProcessRun } from '../src/index.ts'
 
 type Script = ConstructorParameters<typeof MockAdapter>[0]
 
@@ -18,7 +19,7 @@ async function setup(script: Script) {
   await ctx.plugin(SubagentService)
   const adapter = new MockAdapter(script)
   ctx.llm.registerAdapter(['mock'], adapter)
-  const parent = ctx.agentLoop.create(AgentId('parent'), { provider: 'mock', model: 'mock' })
+  const parent = ctx.agentLoop.create(SessionId('parent'), { provider: 'mock', model: 'mock' })
   return { ctx, parent, adapter }
 }
 
@@ -30,19 +31,6 @@ function text(blocks: readonly { type: string; text?: string }[]): string {
   return blocks.filter(block => block.type === 'text').map(block => block.text).join('')
 }
 
-describe('depthOf', () => {
-  it('reads zero for a top-level agent and an explicit child depth', async () => {
-    const { parent } = await setup([])
-    expect(depthOf(parent)).toBe(0)
-    expect(depthOf({ options: { subagentDepth: 3 } } as unknown as Agent)).toBe(3)
-  })
-
-  it.each([Number.NaN, 1.5, -1, -0, Number.MAX_SAFE_INTEGER + 1])('rejects malformed depth %s', (value) => {
-    expect(() => depthOf({ options: { subagentDepth: value } } as unknown as Agent))
-      .toThrow('non-negative safe integer')
-  })
-})
-
 describe('startInProcessRun', () => {
   it('returns only after publication, drives a fresh child, and disposes it', async () => {
     const { ctx, parent } = await setup([textResponse('driver answer')])
@@ -51,7 +39,7 @@ describe('startInProcessRun', () => {
     const result = await run.result
     expect(result.stopReason).toBe('completed')
     expect(text(result.output)).toBe('driver answer')
-    expect(depthOf(ctx.agents.get(run.id)!)).toBe(1)
+    expect(ctx.agents.get(run.id)!.options.subagentDepth).toBe(1)
     await run.dispose()
     await run.dispose()
     expect(ctx.agents.get(run.id)).toBeUndefined()
@@ -71,13 +59,55 @@ describe('startInProcessRun', () => {
     await run.dispose()
   })
 
+  it('persists the child depth in its session header', async () => {
+    const { ctx, parent } = await setup([textResponse('child answer')])
+    const run = await startInProcessRun(request(parent), {})
+    await run.result
+    // The recursion budget is durable session data, not only runtime options —
+    // a depth that lived only in AgentOptions would reset to 0 on resume.
+    expect(ctx.agents.get(run.id)!.session.header.delegationDepth).toBe(1)
+    await run.dispose()
+  })
+
+  it('counts a RESUMED child by its persisted header depth, not the absent runtime depth', async () => {
+    // Resume rebuilds runtime options, so the durable header must keep this
+    // depth-1 child from delegating as though it were top-level.
+    const { ctx } = await setup([textResponse('unused')])
+    const resumed = (await ctx.agents.create({
+      sessionId: SessionId('resumed-child'),
+      meta: { parentSession: SessionId('root'), delegationDepth: 1 },
+      agentOptions: { provider: 'mock', model: 'mock' },
+      signal: new AbortController().signal,
+    })).agent
+    await expect(startInProcessRun({ ...request(resumed), maxDepth: 1 }, {}))
+      .rejects.toMatchObject({ name: 'SubagentDepthError', attemptedDepth: 2, maxDepth: 1 })
+  })
+
+  it('lets runtime options deepen but never lower the persisted depth', async () => {
+    const { ctx } = await setup([textResponse('unused')])
+    const parent = (await ctx.agents.create({
+      sessionId: SessionId('deep-parent'),
+      meta: { delegationDepth: 2 },
+      agentOptions: { provider: 'mock', model: 'mock', subagentDepth: 1 },
+      signal: new AbortController().signal,
+    })).agent
+    // Persisted 2 vs runtime 1: the child is depth 3, so maxDepth 2 rejects.
+    await expect(startInProcessRun({ ...request(parent), maxDepth: 2 }, {}))
+      .rejects.toMatchObject({ name: 'SubagentDepthError', attemptedDepth: 3, maxDepth: 2 })
+  })
+
   it('rejects invalid and exceeded depth before publication', async () => {
     const { parent } = await setup([])
     await expect(startInProcessRun({ ...request(parent), maxDepth: -1 }, {}))
       .rejects.toThrow('non-negative safe integer')
     await expect(startInProcessRun({ ...request(parent), maxDepth: 0 }, {}))
-      .rejects.toBeInstanceOf(SubagentDepthError)
-    const maxParent = { options: { subagentDepth: Number.MAX_SAFE_INTEGER } } as unknown as Agent
+      .rejects.toMatchObject({ name: 'SubagentDepthError' })
+    for (const value of [Number.NaN, 1.5, -1, -0, Number.MAX_SAFE_INTEGER + 1]) {
+      const malformed = { options: { subagentDepth: value }, session: { header: {} } } as unknown as Agent
+      await expect(startInProcessRun(request(malformed), {}))
+        .rejects.toThrow('agent subagentDepth must be a non-negative safe integer')
+    }
+    const maxParent = { options: { subagentDepth: Number.MAX_SAFE_INTEGER }, session: { header: {} } } as unknown as Agent
     await expect(startInProcessRun(request(maxParent), {})).rejects.toBeInstanceOf(RangeError)
   })