fix: honor the teardown order on owner unload; make the structured commit unconditional

Adversarial-review findings (own reviewer agent), each verified and pinned:

B1: agents.register() returned a wrapper lambda, so the factory composite's
yield could not identity-nest it — on OWNER unload the unregistration (and
agent/disposed) disposed as a concurrent sibling, firing mid-drain while
the final turn was still closing (pre-existing on master; this branch's
docs re-assert the order, so it must be true). register() now returns the
EXACT cordis effect disposer (the Scope.rawDispose move); the composite
nests it and owner unload runs stop/drain -> unregister -> detach -> scope
like every other path. Regression test pins turn-end before disposed
before detach on owner unload.

B2: the structured two-phase commit could promote a stale stage when a
later capture call REUSED the orphaned stage's call id with a body that
never staged (denied downstream, or invalid args throwing pre-stage). The
runtime's pre-execute listener now clears any stale stage unconditionally
when a new capture call enters the pipeline — only a call's own body can
stage for its commit; the call-id mismatch guard becomes a defensive
second layer. Repro test: blocked capture then same-id invalid call.

C1: an explicit empty toolFilter config now fails at plugin LOAD (the
check is self-contained) instead of killing every delegation at child
setup. C2: Scope.dispose/ScopeHost.dispose @returns state the single-shot
repeat-call semantics honestly.

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

@@ -159,6 +159,13 @@ export function attachStructuredRuntime(childCtx: Context, schema: StructuredOut
         reason: `structured output already recorded: the run is complete, so \`${exec.name}\` is not executed`,
       })
     }
+    // A NEW capture call invalidates any stale stage UNCONDITIONALLY, before
+    // dispatch: only THIS call's own body may stage for this call's commit.
+    // Without this, a stale entry orphaned by an outer short-circuited chain
+    // could be promoted by a later call REUSING the same call id whose body
+    // never staged (pre-execute-denied downstream, or invalid args throwing
+    // before the stage) — reporting success for a value the model saw fail.
+    if (exec.name === STRUCTURED_OUTPUT_TOOL) pending = undefined
     return next()
   }, { prepend: true })
 
@@ -171,13 +178,14 @@ export function attachStructuredRuntime(childCtx: Context, schema: StructuredOut
     this: unknown, exec: ToolExecution, _result: ToolExecutionResult, next: () => Promise<PostToolDecision>,
   ): Promise<PostToolDecision> {
     if (exec.name !== STRUCTURED_OUTPUT_TOOL || pending === undefined) return next()
+    /* v8 ignore start -- defensive second layer: the pre-execute clear above
+     * already drops every stale stage before a new capture call dispatches,
+     * so a call-id mismatch cannot be reached through the tool pipeline */
     if (pending.callId !== exec.callId) {
-      // A stale stage from a different call: an outer listener short-circuited
-      // that call's post-execute chain past this commit, so its verdict never
-      // reached us and the value must never be promoted — drop it.
       pending = undefined
       return next()
     }
+    /* v8 ignore stop */
     const staged = pending
     try {
       const decision = await next()

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

@@ -530,4 +530,42 @@ describe('in-process structured output', () => {
     expect(valid.isError).toBeFalsy()
     await run.dispose()
   })
+
+  it('a later capture call REUSING a stale stage\'s call id never promotes it (unconditional commit safety)', async () => {
+    const { ctx, parent } = await setup([
+      toolCallResponse('c1', STRUCTURED_OUTPUT_TOOL, { answer: 1 }),
+    ])
+    const run = ctx.subagents.start('spawn', structuredRequest(parent))
+    const child = ctx.agents.get(run.id)!
+    // Orphan a stage: an outer short-circuiting post-execute BLOCK on the
+    // first capture (its chain never reaches the commit listener).
+    let blocks = 1
+    ctx.on('tools/post-execute', (exec, _result, next) => {
+      if (exec.name === STRUCTURED_OUTPUT_TOOL && blocks > 0) {
+        blocks -= 1
+        return Promise.resolve({ kind: 'block' as const, feedback: [{ type: 'text' as const, text: 'rejected' }] })
+      }
+      return next()
+    }, { prepend: true })
+    await run.result
+    // A SECOND capture call with the SAME call id whose body never stages
+    // (invalid args throw before the stage): the stale value must not ride
+    // its acceptance.
+    const reused = await ctx.tools.execute({
+      callId: 'c1' as never,
+      name: STRUCTURED_OUTPUT_TOOL,
+      arguments: { answer: 'not-a-number' },
+      agent: child,
+    })
+    expect(reused.isError).toBe(true)
+    // Nothing was ever committed: a fresh valid call is still required.
+    const valid = await ctx.tools.execute({
+      callId: 'c1' as never,
+      name: STRUCTURED_OUTPUT_TOOL,
+      arguments: { answer: 5 },
+      agent: child,
+    })
+    expect(valid.isError).toBeFalsy()
+    await run.dispose()
+  })
 })

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

@@ -184,6 +184,12 @@ export function providerWording(inherits: boolean): { description: string; promp
 }
 
 export function apply(ctx: Context, config: Config): void {
+  // Misconfiguration fails loud AT LOAD (the check is self-contained): an
+  // explicit `toolFilter: {}` would otherwise pass the capability gate and
+  // kill every delegation later, in the child-setup `restrict({})` throw.
+  if (config.toolFilter !== undefined && config.toolFilter.allow === undefined && config.toolFilter.deny === undefined) {
+    throw new Error('tool-subagent: `toolFilter` is configured but names neither `allow` nor `deny` — remove the key or fill the filter')
+  }
   // The tool MIRRORS its provider's lifecycle instead of assuming load order:
   // the cordis Loader starts sibling entries concurrently, so "backend listed
   // first in cordis.yml" does not guarantee "provider registered first", and

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

@@ -510,4 +510,19 @@ describe('dsh-tool-subagent', () => {
     expect(seen?.toolFilter).toEqual({ deny: ['subagent'] })
     expect(seen?.toolFilter).not.toHaveProperty('allow')
   })
+
+  it('an explicit empty toolFilter fails at plugin load, not at first delegation', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SystemPrompt)
+    await ctx.plugin(ToolRegistry)
+    await ctx.plugin(SubagentService)
+    ctx.subagents.registerProvider({
+      name: 'p',
+      capabilities: { outputSchema: false, depthLimit: false, toolFilter: true, persona: false },
+      inheritsParentContext: false,
+      start: () => { throw new Error('unreachable') },
+    })
+    const fiber = ctx.plugin(tool, { provider: 'p', toolFilter: {} })
+    await expect(fiber).rejects.toThrow(/names neither `allow` nor `deny`/)
+  })
 })