Remove the one-consumer bounded-read primitive and shared terminal lifecycle controller, make terminal cleanup one awaited provider operation, and reuse one Code Runtime contract suite. Keep only reproduced cancellation and policy fixes; defer unproven replacement, prompt-attribution, and streaming-frame concerns to scoped markers.
The inline comment called every dunder entry "the Python backend's" slot,
but `__debug__` is a CPython compile-time constant, not a seeded slot;
align the comment with the seam declaration, which is the single home for
why each entry is reserved.
- Worker consumes PORTABLE_RESERVED_WORDS / RESERVED_ERROR_MEMBERS by
their seam names directly, dropping the local re-alias (symmetry with
the other two imported constants).
- Split the reserved-vs-duplicate diagnostics: a backend-owned global now
reports "reserved binding global", not the misleading "duplicate".
- DUNDER_MEMBER uses `__.+__` so a bare `__` (empty middle, not a real
CPython dunder) is not matched; add coverage.
- Worker misuse tests add `a$b` (second-char `$`) and `lambda` (Python
keyword) so the identifier narrowing and reserved-word adoption are
each pinned directly, not only transitively.
- Clarify the seam JSDoc (dunder-vs-explicit-set wording, Python backend
is a later stack PR) and record in the Agent Note the obligation to
widen RESERVED_BINDING_GLOBALS when the bootstrap seeds more globals.
Move the reserved-word, reserved-global, reserved-error-member, and
dunder exclusion sets from the worker backend up to the code-runtime
seam package, and narrow the portable identifier subset to drop the
JS-only `$`. Every backend now imports one contract so a binding
namespace list valid on one backend is valid on all.
Delivers only the seam extension and the worker's adoption; the Python
backend, py-types renderer, and Code Mode language dispatch are later
PRs in the stack that depend on these exports.
The load-time range check rejects a maxWallMs above Node's maximum
setTimeout delay, but the constraint appeared only in the README design
section. Deployments reading the Config field JSDoc, the generated config
catalog, or the README config summary saw maxWallMs described as a
positive finite wall-clock ceiling, so an out-of-range value looked valid
until plugin load failed.
`config.maxWallMs` is only checked for positivity, and it is handed to
`setTimeout`, which clamps any delay above 2^31-1 ms to 1 ms. A deployment
configuring a 25-day wall ceiling therefore gets the opposite of what it asked
for: every run times out on the first tick. The runtime now range-checks the
field at load against MAX_TIMER_DELAY_MS from dsh-timeout and throws, so the
misconfiguration fails loud where it is self-contained instead of silently
inverting the budget.
`computeMs` needs no matching bound: it is compared against measured event-loop
utilization rather than fed to a timer.
The test asserts both the rejection and that the boundary value itself loads.
A direct runtime import of the session package made the unbuilt worker depend on sibling lib output. Use a parity-tested local JSON snapshotter and pin the isolated source closure with a real-worker test.
pkg stores application files in a virtual filesystem, and its
worker_threads hook discovers worker entry points only when they are passed
as filesystem strings. Convert the code-runtime entry with fileURLToPath()
and return the workflow built entry as a string while retaining its
source-mode data URL bootstrap.
Emit worker entry bundles as CommonJS .cjs files. pkg executes a VFS-backed
string-path worker through Module._compile, so an ESM-only entry can be
present in the executable yet still fail when launched. Keep the public hosts
ESM, adapt worker startup accordingly, and align exports, package file lists,
workspace constraints, documentation, and built-worker tests with the actual
artifact format.
Expand the custom-config executable smoke to load the Code Mode and workflow
plugins and script real run_code and zero-agent workflow calls. Require both
tools to return 42 from workers launched inside the pkg VFS, turning worker
support from an asset-presence assumption into an end-to-end runtime
contract.
Update the implemented RFC and verification gates to describe and exercise
the supported built-worker path. This adds no tool or JSON-RPC protocol shape;
it fixes how existing worker-backed capabilities are located and executed in
the single-file distribution.
Two [P1] review findings on the worker runtime:
- maxValueBytes gated and sliced the rendered fallback by UTF-16 code
units, so a multibyte string ("€€€€" under a 4-byte cap) crossed whole
and a truncated multibyte rendering could still run ~3x over budget.
New truncateUtf8Bytes cuts at code-point boundaries under a real byte
budget; prepareValue's fallback and the host's forged-error-text bound
both use it, and the VALUE_RENDER_SLACK comment drops its now-obsolete
"sliced by characters" wrinkle.
- The patched stream write dropped Node's optional encoding/callback
arguments, so a program awaiting flush completion
(write(chunk, resolve)) hung to the wall ceiling and misreported as a
timeout. The shim now fires the callback asynchronously once the chunk
is admitted — including for writes the exhausted budget drops.
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.
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).
The shipped backend of the code-execution seam, per the Code Mode RFC's
worker-thread section: one fresh Node worker per run, executing the
model's TypeScript after a host-side type-strip (wrapped in an
async-function shell so top-level return/await parse, sliced back out
position-preserved), bindings bridged over the message port under
hostile-peer rules (own-property name lookup, at-most-once replies,
post-settlement drops, null-prototype namespaces), logs streamed eagerly
with an in-band truncation marker, and two independent budgets — measured
event-loop busy time (computeMs) plus a never-pausing wall ceiling
(maxWallMs) — funneling into worker.terminate(). env: {} and execArgv: []
keep the isolate hermetic; disposal aborts in-flight runs and awaits
worker exits.
The worker entry loads unbuilt via Node's native type stripping
(src/worker.ts, erasable-only) and ships built as a sibling tsdown bundle
(lib/worker.js); tests/built-lib.e2e.ts pins the built load path under
plain node and joins the built-artifact smoke gate. Unit suites cover the
bootstrap in-process (fake port) and the runtime over real workers,
per-file 100%.
Tianyi Cui
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