# Conflicts: # .agents/notes/implemented/architecture/2026-06-14-session-persistence.md # .agents/notes/implemented/architecture/2026-06-20-package-hierarchy.md # .agents/notes/implemented/architecture/2026-07-02-tool-render-intent-union.md # .agents/notes/implemented/feature/2026-06-14-acp-agent-client-protocol.md # .agents/notes/implemented/feature/2026-06-14-acp-multi-session.md # .agents/notes/implemented/feature/2026-06-18-acp-terminal-and-tool-rendering.md # .agents/notes/implemented/feature/2026-07-19-model-facing-goal-tools.i18n.yaml # .agents/notes/implemented/feature/2026-07-19-model-facing-goal-tools.md # .agents/notes/implemented/feature/2026-07-19-model-facing-goal-tools.zh.md # .agents/notes/implemented/simplification/2026-07-04-trim-acp-bridge-unreachable-surface.md # docs/architecture.i18n.yaml # docs/cookbook/extension-cookbook.i18n.yaml # docs/cookbook/extension-cookbook.md # docs/cookbook/extension-cookbook.zh.md # docs/core-data-structures/approval.md # docs/core-data-structures/user-interaction.md # docs/event-producer-consumer.md # docs/persistence-catalog.md # docs/testing.md # docs/tool-catalog.md # examples/acp-agent/tests/fixtures/live-mode-switching-2026-07-07.session.jsonl # examples/acp-agent/tests/snapshots/cordis-inspect-jsdoc/stdout.expected.jsonl # examples/acp-agent/tests/snapshots/permission-switching/session.jsonl # packages/goal/tool-goal/README.md # packages/ui/acp/README.md # packages/ui/acp/acp-feature-support.md # packages/ui/acp/src/index.ts # packages/ui/acp/tests/bridge.spec.ts # packages/ui/acp/tests/dispose.spec.ts # packages/ui/acp/tests/edges.spec.ts # packages/ui/acp/tests/turns.spec.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), and the out-of-process subagent-acp backend builds on the subagent-subprocess library (the credential env scrub, the dispose ladder, isolated config dirs). Tests replace only the child boundary with package-local fixtures.
The proposal and design rationale: .agents/notes/implemented/feature/2026-06-21-subagent-capability-seam.md.