Tianyi Cui
25eccdaedc
Address four findings from the first Codex review round: - Contain subagent/start|end listener throws (emitContainedStart/End): a thrown lifecycle listener could escape SubagentService.start() before the caller received the live run to dispose it (a leaked child), and a thrown subagent/end listener could surface as an unhandled rejection on the detached result-settle hook. Both emits now log-and-contain, mirroring the agent registry's agent/created|disposed containment. - Make the model-facing tool name configurable (Config.toolName, default subagent). The docs say to load dsh-tool-subagent once per provider to expose multiple transports, but the hardcoded name made the second load throw a duplicate-tool-name error; a distinct toolName per load is now required and documented. - Reach the per-file 100% coverage gate: tests for the subagent/end error branch, lifecycle-listener containment, every stopReasonError arm + the merge-extensible default, the multi-provider toolName path, agentOptions forwarding, and the direct-apply schema-bypass fallbacks. - Document the seam vocabulary in docs/core-data-structures/subagent.md with verbatim type-equiv blocks + manifest entries, and link it from core.md (a brand-new core/seam type the doc-sync gate cannot detect on its own).
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 |
tool-subagent/ |
Model-facing subagent delegation tool over ctx.subagents |
(registers on ctx.tools) |
The interface lives at subagent/subagent/. Provider implementations live in their own packages — the in-process dsh-subagent-spawn / dsh-subagent-fork and the out-of-process dsh-subagent-acp — plus the test-only dsh-subagent-mock in support. All product packages except the mock.
The proposal and design rationale: docs/rfc/proposed/feature/2026-06-21-subagent-capability-seam.md.