Structured output on the subagent seam: schema subset, capture runtime, spawn/fork support

Carved out of #170 per review feedback — the foundation the workflow tool
builds on, now standing alone on master:

- dsh-tools: the structured-output JSON Schema subset (StructuredOutputSchema,
  assertSupportedOutputSchema, validateStructuredValue) — rejects loud outside
  the enforced subset, listing every violation
- dsh-subagent: SubagentStartRequest.outputSchema / SubagentResult.structured
  become a real capability; the service rejects a schema'd request whose
  provider lacks it
- dsh-subagent-inprocess: the shared structured runtime — one global
  structured_output capture tool, a prepend final-assembly listener that
  strips the placeholder for plain agents and swaps in the run's own schema
  (plus the calling instruction as a trailing section) for structured
  children, an agent/turn-continuation veto once captured, and the
  capture/nudge loop in the run driver (structuredNudgeRetries, cancellation
  honored mid-nudge); lifetime refcounted by backends and live runs
- subagent-spawn / subagent-fork flip outputSchema: true

One deliberate divergence from the #170 revision: the backends do NOT add
'tools' to their plugin inject. Doing so deferred their apply past the todo
plugin, and the delegation tool mirrors provider lifecycle — so the
model-visible tool order of every existing prompt changed, invalidating every
recorded snapshot fixture. The runtime now gates its capture-tool registration
on tools availability itself (sync when live, a scoped inject fiber when the
Loader starts the backend first), keeping this PR byte-invisible to existing
transcripts: all 35 snapshot scenarios pass against master's fixtures
unchanged.
This commit is contained in:
Tianyi Cui
2026-07-06 23:29:08 +08:00
parent 0606cd559c
commit 74502fa8c2
28 changed files with 1570 additions and 62 deletions

View File

@@ -20,7 +20,7 @@ interface SubagentCapabilities {
## The start request
What a caller asks for when starting a subagent. The tool layer builds this from the model's `{ description, prompt }` plus its own config; the service validates the start-time capabilities against the named provider, then passes it to `provider.start`. `parent` is REQUIRED — in-process backends read `parent.session.header` for the working directory, the `parentSession` lineage, and the delegation depth. The three optional fields (`outputSchema`, `maxDepth`, `toolFilter`) each gate on the matching `SubagentCapabilities` flag.
What a caller asks for when starting a subagent. The tool layer builds this from the model's `{ description, prompt }` plus its own config; the service validates the start-time capabilities against the named provider, then passes it to `provider.start`. `parent` is REQUIRED — in-process backends read `parent.session.header` for the working directory, the `parentSession` lineage, and the delegation depth. The three optional fields (`outputSchema`, `maxDepth`, `toolFilter`) each gate on the matching `SubagentCapabilities` flag. `outputSchema` is an object-rooted JSON Schema within the subset `assertSupportedOutputSchema` (dsh-tools) enforces — a schema outside it is rejected loud at start; the in-process backends realize it with a forced `structured_output` capture tool (see the [driver README](../../packages/subagent/subagent-inprocess/README.md)).
```ts type-equiv
interface SubagentStartRequest {
@@ -28,7 +28,7 @@ interface SubagentStartRequest {
parent: Agent
signal?: AbortSignal
agentOptions?: AgentOptions
outputSchema?: SchemaSpec
outputSchema?: StructuredOutputSchema
maxDepth?: number
toolFilter?: { allow?: string[]; deny?: string[] }
}