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deepseek-harness/packages/subagent/subagent-spawn
Tianyi Cui 74502fa8c2 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.
2026-07-06 23:29:08 +08:00
..

@deepseek-ai/dsh-subagent-spawn

The in-process spawn subagent backend: a SubagentProvider that runs each child as a fresh child Agent on the same cordis context (ctx.agents) — its own session, its own (or the parent's) model, zero inherited conversation. The cheapest transport, reusing the agent factory's quiescent AgentHandle teardown.

The run mechanics live in the shared @deepseek-ai/dsh-subagent-inprocess driver (startInProcessRun); this backend just passes no seed (a fresh child). The fork backend is an independent peer over the same driver — neither knows about the other.

What it does

start(request) delegates to startInProcessRun(ctx, request, { providerName, structuredNudgeRetries }) with no seed: a fresh child agent with the parent's cwd/parentSession lineage and (by default) the parent's model. See the driver README for the full lifecycle (depth check, one-shot drive, result read, dispose).

Capabilities

{ outputSchema: true, depthLimit: true, toolFilter: false }. It constructs the child, so it enforces a recursion cap, and it supports structured output via the driver's shared structured runtime (the backend acquires it for its plugin lifetime; each structured run holds its own acquisition until it settles). Tool-scoping is deferred (the service rejects a request needing it before start runs).

Config

Key Meaning
providerName Registry name on ctx.subagents (default spawn).
structuredNudgeRetries How many times a structured run re-prompts a child that finished cleanly without calling structured_output (default 1).