The seam shipped without its own RFC — the reconstructable-requests RFC
was amended with the mechanics, but the decision record (why a
compose-once frozen prefix, and what the per-request before/after shape,
a system-prompt section, a durable history opener, per-turn composition,
and a dedicated session event each lost to) had no home. Implemented
lifecycle, feature class, dated to the first commit of the work.
createScope(ctx, key) mints a tagged context over a synchronously-usable
no-op-plugin fiber (one fact drives visibility AND lifetime); scopeOf reads
the tag through the prototype chain; scopeTarget(base, key) builds the
scope-filtered dispatch carrier over cordis Context.filter, composing the
base's own filter, branded Scoped<T> and runtime-marked for the dev
invariants. Scope.rawDispose exposes the exact cordis disposer so a
composite effect can nest the scope's teardown at its yield position.
- spill-policy validates maxInlineBytes as a non-negative integer at LOAD, so a
bad config fails the deployment instead of letting a negative value reach
TextRetainer and turn every oversized-result call into an isError.
- Document the spill seam vocabulary in docs/core-data-structures/spill.md
(SaveTextSpill/SpillOwner/SpillSource/SpillRef/SpillPath, verbatim + type-equiv
gated) and index it from core.md, matching the other capability seams.
The seam gained sessionPrefix between fullSystemPrompt and signal in
18d478bc, but the compact README member table and the compaction
core-data-structures page still showed the 3-arg form and listed only
agent/system/signal as what pre-step supplies. The generated service
catalog was already correct; only these two prose homes drifted.
A cancel/dispose landing inside the first agent/session-prefix waterfall
used to commit the listener chain's return value to the instance cache
before the interruption check dropped the turn; an abort-aware listener's
degraded fallback would then ship on every later request of the instance.
The commit now happens only after the composition survives the
interruption check — the cache only ever holds a fully composed prefix,
and the next turn recomposes under a live signal.
Oversized plain-text tool results now spill to a session-scoped file and
return a bounded preview plus the spill path, so a verbose result stays
readable via `read` without consuming the next model request in full.
- dsh-spill: minimal SpillFiles seam (saveText → session-scoped SpillPath)
- dsh-spill-local: private 0700 session dirs, traversal-safe names, exclusive
owner-only writes
- dsh-spill-policy: tools/post-execute transformer; no-op unless maxInlineBytes
is set; skips read; best-effort on save failure (never turns a success into
an isError)
web_fetch is the showcase — no tool-specific spill code. The coding-agent
example loads the stack so its keyless Loader smoke guards the namespace-plugin
export shape. Snapshot gap for a transcript-visible web_fetch spill is recorded
in the RFC's Consequences (ACP replay is keyless and cannot hit the web).
ds-review-bot critical (follow-up): on the first step of a resumed or
seeded/forked instance, auto-compaction ran before runStep composed
this instance's prefix, so the gate read the PREVIOUS instance's logged
prefix from the header fold — a contributor that grew across
resume/fork (skills added, AGENTS.md grown: exactly the
environment-dependent case) could under-gate and ship an over-window
first request.
The loop now composes agent/session-prefix before the instance's first
agent/pre-step (still once per instance; runStep just reads the cache),
and agent/pre-step carries the composed prefix to its listeners.
CompactService.compactIfNeeded gains the sessionPrefix parameter;
BasicCompactService.estimatePressure gates on the handed value — the
header-fold read is gone, so the estimate is exact at every step
including a resumed/forked instance's first. Composition moving before
the boundary snapshot also means a composing listener's session append
now joins the CURRENT request (documented on the seam).
New coverage: composition precedes pre-step and the seam receives the
composed prefix; cancel and disposal landing inside the composition
window drop the step cleanly; the compact gate test hands the prefix
directly.
Verifies the namespace plugin has no default export and preserves
name/inject/Config through Loader.unwrapExports — the same guard
pattern as dsh-tool-web, per the packages/AGENTS.md convention.
Connects to an external MCP server and registers its tools on
ctx.tools. Supports stdio (child process) and Streamable HTTP
transports. Credential-shaped env vars are scrubbed before forwarding
to child processes.
- Plugin lifecycle: connect, sync tools, re-sync on ToolListChanged,
dispose unregisters and closes
- Full JSDoc on all exports (@param/@returns on functions)
- 100% per-file coverage (apply lifecycle, args coercion, env scrubbing)
- Config catalog regenerated
The seam's structured-clone boundary admits values JSON does not (BigInt,
Map, circulars), while tool/code-dispatch events must be JSON-appendable —
left unhandled, a sub-call could execute and then fail at logging time.
The bridge now JSON-normalizes binding arguments BEFORE dispatch (a value
that does not survive rejects that one call), so the dispatched form and
the logged form are the same JSON value by construction.
Adds the missing core-data-structures coverage the catalog policy
requires for non-spine seam vocabulary: the code-runtime.md sub-page
with drift-checked type-equiv blocks for all six seam types, the core.md
sub-page row, the type-equiv manifest entries, and LINK_MAP entries so
the generated service signature links CodeRunRequest/CodeRunResult;
cordis/config catalogs regenerated.
New group packages/code-runtime/ with the interface package
@deepseek-ai/dsh-code-runtime, per the Code Mode RFC: abstract CodeRuntime
service (run() resolves program failures as an error field, rejects only
for seam misuse), the CodeRunRequest/CodeBindingNamespace/CodeRunResult/
CodeLogEntry/CodeRunFailure vocabulary, and readonly language/isolation
backend descriptors. Registered in the tsconfig maps, packages/README,
architecture service map, and the doc-graph service-role classification;
catalogs regenerated.
The RFC's one forward path token to the worker package becomes an npm-name
mention until PR3 creates that directory (verify-package-paths is
drift-scoped: the now-existing group made the token checkable).
docs/architecture.md ceiling 1630 -> 1640: the doc gained a genuinely new
capability-service row; the row itself is already minimal.
Budget expiry terminated the worker but nothing cancelled an in-flight
host-side sub-dispatch, and a late dispatch could append events after
run_code returned. The bridge now owns a run-scoped AbortController
(follows exec.signal; fired on any run settlement), sub-dispatches get
the run signal, and run_code returns only after the dispatch queue
drains — no post-settlement appends, per dispose-to-quiescence.
(A1) Scope the wire-collapse guarantee honestly: systemPrompt.tools() is
a public multi-provider API, so the mode governs the registry's
contribution (the only shipped source); deliberate extra providers own
what they add, and the shipped-configuration invariant is test-pinned.
(A2) Replace pause-on-pending-RPC timeout with two independent budgets:
computeMs metered by worker.performance.eventLoopUtilization() busy time
(unfoolable by an un-awaited decoy dispatch; probe-verified) plus a
never-pausing maxWallMs ceiling.
(A3) Specify sub-call additionalContext as deliberately suppressed in
the MVP (immediate inject would break call/result adjacency; the plural
channel is named follow-up work).
(B) Orphan-process caveat vs bash-local's group kill; null-prototype
binding namespaces (__proto__/constructor names); per-PR doc artifacts
(packages/README row, architecture service map in PR2, config/tool/
persistence catalogs per owning PR); engines range corrected to
^22.19.0 || >=24.0.0.
Research finding: a SessionEventMap member is a log event — JSDoc prose
required, @mode is a hard error there, and docs/persistence-catalog.md
must be regenerated (todo/write is the log-only precedent). PR4's plan
now names both.
Own adversarial pass finding: a static inject on the registry would gate
ctx.tools (and every tool plugin) on a code runtime existing even under
mode 'native'. The RFC now names the sanctioned pattern: soft
ctx.get('codeRuntime') at use time (the agent-loop sessionPersistence
precedent) with absence failing loud in the provider thunk.
Supersedes the add-on-plugin + node:vm-stub draft in place (still proposed/):
code mode becomes a first-class ToolRegistry presentation mode
('native' | 'code' | 'both'), execution goes behind a new ctx.codeRuntime
capability seam whose shipped backend is one fresh Node worker thread per
run (type-strip, empty env, resource limits, hard terminate), at
bash-equivalent trust with no unsafe-flag ceremony. Renames the file to
2026-06-15-code-mode.md and regenerates the RFC index.
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
Two ds-review-bot findings:
The seam JSDoc claimed extending 'await next()' composes in
registration order — false for the append form: the waterfall unwinds
innermost-first, so appending places later-registered contributions
first. The canonical contribution is now documented as the PREPEND
'[mine, ...await next()]' (registration order on the wire), with the
append form's reverse-order behavior stated explicitly; the ordering
test now uses the canonical pattern in both listeners.
scrubRequestHeaders tokenized only system/tools, so a fixture recording
a composed session prefix would carry its raw text (workspace-specific
churn/leak). The scrubber now maps each header/delta messagePrefix
entry to a {{messagePrefix}} token — count stays a structural fact,
absence stays absent, the empty-array transition stays visible — with
normalize.spec coverage for the header, delta, absence, and odd-shape
paths.
Brings in the refreshed base (master merged through the stack after #203
and #205 landed), including the acp-snapshot extraction (#204), and
re-ports this PR's snapshot-suite extensions onto the extracted package:
- dsh-acp-snapshot's Scenario gains headerClass and configPath; the suite
factory pins the request header PER CLASS (construction rejects a
missing or duplicated class pin), forwards a scenario's configPath to
the harness (RunOptions.configPath overrides AgentUnderTest.configPath),
and a new fixtures meta-test asserts every pinning fixture carries
exactly one request/header and no deltas.
- The acp-agent example's thin scenario table re-registers code-mode-turn
and both-mode-turn with their overlay configs and per-class pins; the
committed fixtures replay unchanged.
- The package's synthetic suites cover the new surface (explicit
headerClass on one suite, the default on the other, a configPath
override through the fake bin, and the two construction throws).
Review discussion converged on the industry shape (Claude Code caches
user context per conversation; Codex separates initial context from
diffs; Kimi appends at continuation boundaries to protect prompt
caching): stable openers belong in a compose-once prefix, mid-session
changes belong in append-only history — not in a per-request slot.
agent/session-prefix fires ONCE per loop instance, lazily on its first
request-building step: the composed Message[] is deep-frozen, cached on
the transmission bookkeeping, recorded as EpochHeader.messagePrefix on
the anchoring 'initial'/'resume' snapshot, and reused verbatim for
every request the instance sends — prefix stability is structural, not
a producer discipline, and a resume recomposes with attributable drift.
The request is messagePrefix + boundary snapshot.
The per-step RequestAdvice/RequestAdviceContext surface and the
messageSuffix header field are dropped: the tail slot had no consumer,
and every current update pattern (new AGENTS.md discovered, memory
update, skills change) routes through the existing append-only history
channels — inject(), tools/post-execute additionalContext,
prompt-submit additionalContext — each paid once and prefix-cached
thereafter. The messagePrefix delta arm stays for codec totality; the
loop never produces one in practice.
The RFC's deployment-policy decision is unchanged; state the current
mechanism in place — the per-tool budget is declared on ToolDefinition
(timeoutMs, set by the owning tool plugin from its config) and the
enforcer is zero-config, so a mistyped tool name is impossible.
Regenerate config-catalog (timeout-policy -> no-config; tool-web gains
fetch/searchTimeoutMs), the event graph (tools/change loses its
timeout-policy consumer), the ToolDefinition type-equiv block, and a
source-line drift in the cordis services catalog.
The dsh-tools half of the Code Mode RFC (its fourth, final change): the
registry gains its first config — mode: native | code | both — and OWNS how
its tools reach the model. 'code' contributes exactly one wire tool,
run_code, plus a lazy tools:sdk prompt section declaring every other tool
as a generated TypeScript API (jsonSchemaToTs: total over the defineTool
subset, unknown degradation, lexicographic byte-identical rendering);
'both' ships both representations; 'native' is byte-for-byte the old
behavior. Non-native modes fail every assembly loudly without a
typescript-language ctx.codeRuntime.
run_code's dispatch bridge: JSON-normalizes each binding argument before
dispatch (what dispatches is what the tool/code-dispatch event logs — the
append can never fail on payload shape; BigInt/circulars reject that one
call), serializes all program tool calls through a per-run queue (even
Promise.all — no concurrency-safety metadata yet), routes every sub-call
through tools/pre-execute → tools/post-execute (a deny rejects the
program-side promise), drops sub-call additionalContext (no safe outlet
mid-run; pinned), owns a run-scoped abort that follows the outer signal in
and fires on settlement (in-flight sub-dispatch aborted, queued abandoned,
queue drained before returning), and converts a failed run into
CodeRunFailedError → a structured isError carrying kind + captured logs.
tool/code-dispatch joins SessionEventMap by declaration merging (log-only;
deriveMessages ignores it).
The composed surface: the tools config forwards through agent-core and
both app packages; examples/code-agent + demo:code run the worker runtime
under mode code (keyless boot smoke + a with-key e2e proving the collapsed
[run_code] header, the dispatch events, and the file the program wrote);
two new snapshot scenarios (code-mode-turn, both-mode-turn) record the SDK
section, collapsed header, dispatch events, and result card — each its own
header-pinning class (the harness gains per-scenario config overlays and
per-class pins). Catalogs, graphs, cookbook, hooks-bridge notes, and the
RFC (moved to implemented/, restructured to decision-era headings) updated
in the same change.
Two findings from the GitHub review bot on the ready PR:
The tsdown two-entry build emitted the shared bootstrap module as a
lib/bootstrap-*.js chunk imported by both bundles, which the package.json
files whitelist (deliberately exact) omitted — a packed install had
dangling imports. The package now runs two single-entry builds, so each
bundle inlines its own bootstrap copy and every shipped file is
self-contained.
prepareValue admitted any cloneable value whose BOUNDED inspect rendering
fit maxValueBytes, so a huge container with a compact rendering (a
50k-element array renders as '... N more items') crossed the port raw,
bypassing the cap on both sides. The cap now measures the value's real
cross-boundary size — exact bytes for strings, the structured-clone wire
size (v8.serialize) for everything else — and oversized containers cross
as their bounded rendering instead.
ds-review-bot flagged that a typo'd or stale config key (e.g. web_fech for
web_fetch) silently applies the timeout to nothing — the tools/execute lookup
just never matches. Mirror dsh-tool-subagent's lifecycle-driven handling of a
configured-but-unregistered provider: on every tools/change (and once at load),
logger.warn each configured name still absent from ctx.tools, warning each name
at most once so a late registration silences it. Not a load-time throw — the
tool set is dynamic (cordis.yml load order, HMR), so a real tool may register
later.
Declare inject = ['tools'] since the plugin now reads ctx.tools synchronously
in apply (previously only inside event callbacks). Regenerate config-catalog
(Requires: tools) and event-producer-consumer graph.
The host's message listener trusted the compile-time WorkerToHost shape on
traffic from a peer that runs model code: postMessage(null) threw in the
listener and crashed the host process; forged log/done messages bypassed
maxLogBytes/maxValueBytes (the worker-side LogBuffer and prepareValue cap
only honest flows); and the error-reply renegotiation re-echoed a forged
non-cloneable call id, throwing outside any catch.
Every inbound message now passes a runtime shape gate that validates and
REBUILDS it field by field (junk drops without a throw; call ids must be
numbers, so replies are always clone-plain; forged extra fields never ride
along). One host-side ledger bounds everything landing in logs — honest
port entries, forged ones, and stray pipe bytes — at the single documented
maxLogBytes, with the shared in-band truncation marker emitted host-side
when the ledger trips first; the completion value is re-capped host-side
through the same prepareValue (with exactly the truncation suffix as slack
so honest worker-capped values pass unchanged), and done error text is
bounded. Also folds the stray-capture budget into that shared ledger
(round-1 finding B: it was a second maxLogBytes on top of the documented
shared cap).
Tianyi Cui
Yichen Jiang
Dudu-0223
lintianle
pku-xht
kingwl
Ziya