Tianyi Cui
7c5133488a
The exact-disposer fix (5fbac8be B1) repaired agents.register but left the same wrapper (return () => void dispose()) at seven sibling sites: tools.register, tools.restrict, systemPrompt.section/tools/variable, agents.setFactory, and subagents.registerProvider. A wrapper makes correct composite usage unrepresentable — the exact disposer cannot be recovered, so a generator effect yielding it leaves the inner effect disposing as a CONCURRENT SIBLING on owner unload, silently reproducing B1's ordering corruption. The exact disposer serves both usages (composite-nestable AND fire-and-forget callable); all seven now return it, typed () => Promise<void> | void, with the convention pinned by a discriminating test: an async-link composite probe that passes with the exact disposer and observes the sibling unregistration firing mid-drain with a wrapper. Re-auditing also surfaced that B1 itself SHIPPED a full-lint failure: it changed register()'s return type without updating cross-file consumers (agent.spec.ts dispose() statements, tool-bash's disposer list), which the staged-scoped pre-commit lint never saw — pnpm run lint was red at HEAD. Those three sites and this change's own fallout are fixed together: tests now await disposers (stronger — they observe the full unwind), sync paths void them, and the two annotation sites carry the honest union type. agents.register's README line had drifted the same way (B1 updated the JSDoc, not the README) — all seven README signatures now match; services catalog regenerated.
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.