The group's convention is package suffix == provider default
(subagent-acp/'acp', subagent-spawn/'spawn', subagent-fork/'fork'), and the
provider default became dsh-sdk in the last review round — so the package
follows: @deepseek-ai/dsh-subagent-dsh-sdk at
packages/subagent/subagent-dsh-sdk, plugin name subagent-dsh-sdk,
diagnostics prefixed subagent-dsh-sdk:. The dsh echo has precedent
(dsh-llm-deepseek). Directory, fixture path, knip/tsconfig/examples
registrations, catalogs, READMEs (en+zh), and the Agent Note follow; the
sdk-client dispose ladder moves to its own module (src/dispose.ts) with the
deterministic FakeChild tier tests restored alongside it.
Master's #660 replaced dsh-subagent-subprocess with the dsh-subprocess
capability seam (ctx.subprocess + scrubbedParentEnv, tree-scoped teardown)
and moved subagent-acp onto it. Convergence for this branch's packages:
- The shared out-of-process provider vocabulary this branch had grown in
the deleted library (NO_START_CAPABILITIES, assertPositiveFinite, cwd
resolution, settleRunResult, subprocessRunHandle) moves into the subagent
seam package as out-of-process.ts — it enforces subagent-seam contracts,
not process mechanics, and both out-of-process backends now import it
from there (subagent-acp keeps master's shape otherwise).
- subagent-sdk spawns THROUGH the SDK client (the subprocess README's
documented exception for SDK-managed transports) and now applies the
seam's scrubbedParentEnv() + explicit-env merge in place of the deleted
buildChildEnv.
- sdk-client inlines the EOF→SIGTERM→SIGKILL ladder as private helpers (it
runs outside any harness context, so it cannot ride ctx.subprocess).
- The child harness fixture gains the now-required dsh-subprocess-local
entry for bash-local; the fixture cordis.yml keeps exercising the
shipped provider default.
- examples/jsonrpc-agent gains its first snapshot suite (sdk.snapshot.ts):
the real dsh-jsonrpc-agent runtime driven through the real dsh-sdk-client,
keyless llm-replay behind a new cordis.snapshot.yml overlay; three recorded
scenarios (text turn, bash tool, spawn subagent) pin the notification
stream, the SDK turn result, and the persisted parent+child session logs.
- Bilingual READMEs for dsh-sdk-protocol / dsh-sdk-client / dsh-subagent-sdk;
sdk/ and subagent/ group tables extended; dsh-jsonrpc README points at the
extracted protocol package; Agent Note (en+zh) owns the decision.
- The proposed make-jsonrpc-directional note is updated for the transport's
new home and its second (client) consumer.
- Model Experience sentence allowlist entries for the two client-side
packages; module graph + config catalog regenerated; i18n pairings
recorded. doc-sync passes 24/24.
Review direction (tianyicui, PR #660): in a stacked PR, change all other
process-running places to use the new service.
- lsp-local: LspConnection spawns through ctx.subprocess (piped protocol
streams + a no-spill collected stderr tail); its private process-tree
helpers (POSIX group signalling, Windows taskkill, liveness polling) are
deleted in favor of the seam's handle verbs, and its buildChildEnv now
rides scrubbedParentEnv (LSP children also stop inheriting stale DSH_*).
The plugin injects 'subprocess'; compositions/tests mount
dsh-subprocess-local.
- subagent-acp: the ACP child spawns through the seam (piped ndjson streams,
inherited stderr); spawn failure surfaces through done-rejection into the
same startup race; disposal is handle.dispose with the plugin's configured
graces. dsh-subagent-subprocess is DELETED — its dispose ladder and scrub
are the seam's, and the isolated-config-dir helper had no consumer.
- mcp-client, pty-local, sdk-helper: adopt scrubbedParentEnv as the one
scrub definition (their spawns stay put by ownership: the MCP SDK and
node-pty own those calls; the SDK wizard runs outside any composition).
- Coverage: per-file 100% over every touched src file, with each v8 ignore
carrying a platform or contract reason; new suites cover stdio
dispositions, the dispose ladder tiers, injected-win32 tree semantics,
waitForExit, settled-kill/terminate no-ops, and spawn-failure disposal.
- Docs: consumer-migration Agent Note (en; zh follows in this PR), seam note
updated in place, subprocess.md rewritten for the reshaped vocabulary
(type-equiv re-registered), READMEs and SERVICE_ROLES updated, taskkill
added to knip ignoreBinaries.
The extracted library's name sat one edit away from @deepseek-ai/dsh-subagent-inprocess
(process/inprocess), inviting a typo'd import to silently resolve to the wrong
package. subagent-subprocess also reads as the deliberate counterpart to
subagent-inprocess (in-process vs. subprocess), matching how the two shared
drivers actually differ.
Package directory, npm name, module doc, JSDoc module tags, test-file name and
its temp-dir prefixes, the subagent-acp import and its Config/tsconfig/package.json
references, root tsconfig.json/tsconfig.build.json/knip.json entries, and the
packages/subagent group README all renamed together; regenerated
docs/module-graph.md and docs/config-catalog.md. Pure rename — no behavior,
export, or Config shape changed.
The credential env scrub (SENSITIVE_ENV_PATTERN/buildChildEnv), the
spawn-failure capture (spawnFailure), the child-exit waits
(waitForExit/exitsWithin), and the stdin-EOF -> SIGTERM -> SIGKILL dispose
ladder move out of subagent-acp into a new pure library package (the
subagent-inprocess shape), with the ladder taking its two grace periods as
parameters — defaults stay in the plugin Config. New isolated-config-dir
helpers (mkdtemp create, best-effort remove; a pinned dir is never removed)
land alongside for the CLAUDE_CONFIG_DIR / CODEX_HOME redirection the RFC
names.
The ACP backend migrates onto the library with no semantic change: its suite
passes with import-path edits only. bash-local keeps its sibling copy, per
the RFC's blast-radius call.
RFC: docs/rfc/proposed/feature/2026-07-07-claude-code-and-codex-subagent-backends.md
The shared run driver lived inside dsh-subagent-spawn, so the spawn package
carried fork-aware seeding logic and dsh-subagent-fork depended backward on
dsh-subagent-spawn — the two in-process backends were not independent.
Move the driver (startInProcessRun, depthOf, SubagentDepthError,
InProcessRunOptions) into a new pure-library package
@deepseek-ai/dsh-subagent-inprocess that registers nothing. spawn and fork now
both depend only on that driver and neither knows about the other; spawn no
longer re-exports it and fork no longer imports from spawn.
Also wire BOTH backends in examples/coding-agent/cordis.yml (config-only): load
dsh-subagent-spawn + dsh-subagent-fork + two dsh-tool-subagent instances with
distinct toolNames (subagent → spawn, subagent_fork → fork), demonstrating that
exposing multiple transports needs no code change.
The first OUT-OF-PROCESS subagent backend, proving the seam generalizes past the
in-process backends. @deepseek-ai/dsh-subagent-acp runs each child agent in a
spawned subprocess, driven over the Agent Client Protocol as the CLIENT — the
direction-inverted twin of the dsh-acp server bridge. Point the configured
command at the acp-agent example and the harness talks to its own process.
- Fresh process per run: start spawns, runs one ACP session (initialize →
newSession → prompt), dispose kills the subprocess and awaits its exit.
- Minimal client stub: advertises no fs/terminal; accumulates agent_message_chunk
text as the result output; auto-answers session/request_permission by a
configured policy (reject default / allow). No start-time capabilities (an
out-of-process child can't enforce the parent's depth/tool-filter); ignores
request.parent; injects only `subagents`.
- StopReason mapping (end_turn→completed, cancelled→aborted, …); result resolves
error/aborted on a child failure, never rejects (seam contract).
- Security: credential-shaped ambient env vars are scrubbed; the child's own key
is forwarded only via explicit config.env. A spawn-level error (ENOENT) is
captured and raced against the ACP drive so a bad command settles error rather
than crashing the parent.
Testing designed at every tier: keyless integration drives a scripted mock ACP
server subprocess (cancellation incl. the pre-newSession race and a
torn-pipe-after-cancel, permission auto-answer, non-message updates, spawn
failure, HMR, export shape) at 100% coverage; a with-key e2e drives the REAL
acp-agent example process (PONG + real file write, verified on disk) — the
harness driving itself. Snapshot coverage of an ACP child is deferred as
TODO(acp-subagent-replay) (each child is its own process with its own replay).
Stayed on @agentclientprotocol/sdk 0.25.1: the proposed 0.28.x bump only
deprecates the stable ClientSideConnection/AgentSideConnection API this layer
uses (33 sites incl. the server bridge), turning no-deprecated red across code
this PR shouldn't rewrite — that fluent-API migration is its own follow-up. The
backend needs nothing 0.28.x adds.
This completes the subagent seam stack (PR1 interface → PR2 in-process → PR2.5
snapshot infra → PR3 ACP); the seam RFC moves to implemented/, amended.
The second PR of the subagent seam: the two in-process backends that run a
child agent on the same cordis context, reusing the agent factory's quiescent
AgentHandle teardown. Both register on ctx.subagents (PR1's named-provider
registry) and share one run driver.
- dsh-subagent-spawn: a FRESH child via ctx.agents.create — own session, the
parent's model by default (overridable), zero inherited conversation. Also
exports the shared in-process run driver (startInProcessRun): mint ids, stamp
cwd/parentSession-lineage/depth, drive the one-shot (send → whenIdle), read
the last assistant/message + turn/end reason, dispose to quiescence.
- dsh-subagent-fork: a child SEEDED with the parent's balanced completed-turn
prefix (the log up to and including its last turn/end), so the child inherits
context. The in-flight unbalanced turn is excluded — a raw seed would fail the
invariants replay. Proven: a regression test goes red if the boundary seeds
the open turn.
- Seam extension: CreateAgentOptions.seed, threaded through AgentLoop.createAgent
→ ctx.sessions.prepare({ seed }) (the primitive resume already used). This is
the fork-lineage path the TODO(sub-agents) markers anticipated.
- Depth: a merge-extensible AgentOptions.subagentDepth (0 top-level, parent+1 for
a child); the depthLimit capability refuses a spawn past request.maxDepth.
Tests: real-loop unit tests for both backends (mock MODEL only, real loop +
invariants), a multi-subagent test (one parent drives a fork AND a spawn child
then keeps working), and a with-key e2e (a real parent delegates via the
`subagent` tool to a real child that writes a file on disk — world-verified).
100% per-file coverage. The coding-agent demo wires the spawn backend + tool.
Snapshot coverage of nested agents is deferred to a stacked follow-up
(TODO(subagent-snapshots)): dsh-llm-replay is a single global positional cursor
that cannot route calls to a parent vs. a child on one context. Recorded in the
RFC's deferrals and a new AGENTS.md rule: designing a subsystem must design its
test infrastructure END TO END up front, verifying the snapshot/e2e harness can
express the new shape — a gap this plan hit.
Introduce the `packages/subagent/` group and the abstract subagent seam — an
agent delegating to a child agent — as a named-provider registry (`ctx.subagents`),
unlike the single-implementation bash seam, so multiple transports (in-process,
ACP, future A2A) coexist. This first PR lands the interface, a scripted test
backend, and the model-facing tool, validated through the real cordis load path.
- dsh-subagent: SubagentService registry + SubagentProvider/SubagentRun
vocabulary + subagent/start|end events. Start-time capabilities (outputSchema,
depthLimit, toolFilter) are checked pre-start and rejected loud; runtime
capabilities (sendMessage, resume) are optional methods on SubagentRun.
- dsh-subagent-mock (support): scripted provider for keyless, deterministic
tests through the real Loader/export path.
- dsh-tool-subagent: the model-facing `subagent` tool, config-bound to one
provider; synchronous collect with try/finally dispose, signal->cancel
bridging, and non-completed-stop-reason -> isError mapping.
- Proposed RFC documenting the seam, the fork-vs-spawn-as-separate-backends
decision, own-session isolation, synchronous-collect scope, and the deferral
of background/poll/spill to a future unification with bash.
- Wire the new group into tsconfigs, build refs, package hierarchy docs, the
module graph, and the cordis catalog.
RFC: docs/rfc/proposed/feature/2026-06-21-subagent-capability-seam.md
