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# Conflicts: # docs/config-catalog.md # docs/cordis-catalog/services.md # docs/event-producer-consumer.md # docs/rfc/implemented/architecture/2026-06-18-agent-lifecycle-and-ownership-seams.md # docs/rfc/implemented/architecture/2026-06-20-branded-ids.md # docs/rfc/implemented/simplification/2026-06-20-remove-agent-boundary-mirror-events.md # docs/rfc/proposed/feature/2026-07-07-claude-code-and-codex-subagent-backends.md # docs/rfc/proposed/simplification/2026-06-20-unify-agent-and-session-id.md # packages/bash/tool-bash/README.md # packages/bash/tool-bash/src/index.ts # packages/bash/tool-bash/tests/tools.spec.ts # packages/core/agent-loop/README.md # packages/core/agent-loop/tests/properties.spec.ts # packages/core/agent/README.md # packages/core/agent/src/index.ts # packages/guard/repeat-tool-guard/src/index.ts # packages/hooks/hooks-claude/tests/bridge.spec.ts # packages/subagent/subagent-acp/tests/mock-acp-server.ts # packages/ui/acp/tests/dispose.spec.ts # packages/ui/stdio-agent/src/index.ts # packages/ui/stdio-agent/src/stdio-chat.ts # packages/ui/stdio-agent/tests/stdio-chat.spec.ts # packages/util/brand/src/index.ts
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 (no provider; one cleanup effect per run) | — |
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-subprocess/ |
Shared out-of-process machinery: env scrub, dispose ladder, isolated config dirs (pure lib; registers nothing) | — |
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 library with no provider of its own — both depend on it, neither on the other), the out-of-process subagent-acp backend builds on the subagent-subprocess library (the credential env scrub, the dispose ladder, isolated config dirs) and 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.