feat(subagent): enrich subagent/start + subagent/end lifecycle events (observe-only)

A hooks bridge translating SubagentStart/SubagentStop needs to know WHICH kind of
subagent ran and WHAT it produced — Claude Code's hooks carry subagent_type and the
child's final message. Enrich the existing lifecycle emits to match, observe-only:

- agentType: an optional caller-supplied subagent-kind label (CC's subagent_type),
  added to SubagentStartRequest and carried VERBATIM onto both subagent/start
  (SubagentRunInfo) and subagent/end (SubagentRunEndInfo). The seam never interprets
  it. dsh-tool-subagent threads it from a new optional Config.agentType, so a
  deployment exposing multiple subagent kinds (one tool load per kind) labels each.
- lastAssistantMessage: the child's final output (SubagentResult.output), added to
  SubagentRunEndInfo on the settle path so an observer sees what the subagent
  produced without holding the run. Absent on the reject path (no result produced).

Strictly observe-only: both events stay plain emits (subagent/end fires from a
detached .then and awaits no listener). A control-flow subagent/end (awaited
waterfall returning a decision) would need the emit→waterfall reshape, awaiting
listeners before settling, and a provider resume capability — deferred to the
background/steering redesign (FIXME(subagent-continuation) anchors it). RFC:
implemented/feature/2026-06-30-subagent-observe-enrich.md.
This commit is contained in:
Tianyi Cui
2026-06-30 21:29:08 +08:00
parent 60418a5779
commit 7cc7b9cf7f
11 changed files with 225 additions and 10 deletions

View File

@@ -25,6 +25,7 @@ What a caller asks for when starting a subagent. The tool layer builds this from
```ts type-equiv
interface SubagentStartRequest {
prompt: ContentBlock[]
agentType?: string
parent: Agent
signal?: AbortSignal
agentOptions?: AgentOptions
@@ -85,7 +86,7 @@ interface SubagentProvider {
}
```
The service (`ctx.subagents`) emits `subagent/start` when a run begins and `subagent/end` when it settles (see the [events catalog](../cordis-catalog/events-and-services.md)). Both emits contain a thrown listener **per listener** (logged, never propagated): one bad subscriber can neither strand a live run, surface as an unhandled rejection on the detached settle hook, nor starve the listeners registered after it.
The service (`ctx.subagents`) emits `subagent/start` when a run begins and `subagent/end` when it settles (see the [events catalog](../cordis-catalog/events-and-services.md)). Both payloads carry the caller's optional `agentType` label (verbatim from the request — Claude Code's `subagent_type`); `subagent/end` additionally carries `lastAssistantMessage` (the child's final `output`) on the settle path, so an observer sees WHAT the subagent produced without holding the run (absent when the run rejected at the infrastructure level — no result was produced). These are **observe-only** enrichments: both events are plain `emit`s (the `subagent/end` fires from a detached `.then` after the result settles and awaits no listener), so a subscriber observes but cannot change the run. Both emits contain a thrown listener **per listener** (logged, never propagated): one bad subscriber can neither strand a live run, surface as an unhandled rejection on the detached settle hook, nor starve the listeners registered after it.
## In-process backends: depth and seed