547aacee2f
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.
subagent/ — subagent capability family
The subagent seam: an agent delegating work to a child agent. Like the bash and llm families this is a capability seam (see capability seams) — but with one defining difference: multiple provider implementations coexist in one context, registered by name, rather than the single-implementation bash shape. The registry mirrors the LLM adapter registry.
| Package | Role | ctx key |
|---|---|---|
subagent/ |
Abstract subagent seam: named-provider registry + vocabulary | ctx.subagents |
subagent-inprocess/ |
Shared in-process run driver (pure lib; registers nothing) | — |
subagent-spawn/ |
In-process backend: a fresh child agent | (registers on ctx.subagents) |
subagent-fork/ |
In-process backend: a child seeded with the parent's completed-turn prefix | (registers on ctx.subagents) |
subagent-acp/ |
Out-of-process backend: a child agent in a spawned subprocess, driven over ACP | (registers on ctx.subagents) |
tool-subagent/ |
Model-facing subagent delegation tool over ctx.subagents |
(registers on ctx.tools) |
The interface lives at subagent/subagent/. The in-process subagent-spawn / subagent-fork backends share the subagent-inprocess driver (a pure library — both depend on it, neither on the other), and the out-of-process subagent-acp backend ships alongside them here; the test-only dsh-subagent-mock (in support) is separate. All product packages except the mock.
The proposal and design rationale: docs/rfc/implemented/feature/2026-06-21-subagent-capability-seam.md.