Tianyi Cui
0e0f3b2f19
The Codex simplification concern plus the duplication comment on the spawn apply, resolved by deletion: the backend-lifetime holds are gone, so the runtime registers at the first structured run and disposes when the last settles — a deployment that never passes outputSchema carries no always-on global state, and there is no per-backend acquisition block left to extract. The driver spec now drives an INLINE spawn-shaped provider over startInProcessRun, which removes the spawn/fork devDependencies (the test-only workspace cycle); plugin-level structured coverage moves to the backends' own specs (capture through the shipped plugin, mid-run backend unload, seeded fork capture). tools.md, the driver README, and both backend READMEs describe the run-scoped lifetime; the module-graph regenerates without the cycle edges.
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.