P1 review finding: extractMeta timed only the literal's vm evaluation;
materializing the RESULT then read properties ordinarily on the HOST
stack, so a meta literal smuggling a getter (get name() { while(true){} })
could wedge the host outside any timeout — defeating the exact spin
isolation the worker thread exists for.
Rather than harden the evaluator (descriptor walks, AST validation),
delete the mechanism: the workflow's identity now reaches the seam as a
plain JSON field (WorkflowStartRequest.meta), carried by the tool as a
schema-validated `meta` object parameter the model fills directly. The
engine only shape-validates data (validateMeta, every violation named)
and pre-parses the body; the scanner, the vm evaluation, and the
host-side materialization are gone, and with them the hole. A body
still opening with a Claude Code-style `export const meta` statement
gets a pointed SCRIPT_PARSE message (the likeliest authoring slip; a
CC script's body stays drop-in, only its meta header moves into the
parameter). syncTimeoutMs now governs exactly one thing: the initial
synchronous slice inside the worker.
The RFC's decision section is rewritten in place (implemented-RFC
rule); the embedded-meta format moves to alternatives-considered with
the hole as the reason. Tool description, presentation (title now reads
meta.name directly — the textual sniff is gone), seam vocabulary docs,
and catalogs follow.
Pure mechanical rename now that the package's internals are the
worker-thread engine: directory, package name, spec/e2e filenames,
module tags and logger prefixes, tsconfig/knip/run-gates/AGENTS.md
references, example cordis.yml plugin ids, doc links; catalogs
regenerated and the lockfile refreshed.
In-place port of dsh-workflow-vm from the in-process node:vm execution
to one worker thread per run (the workflow-workerthread engine of
PR #215, adopted as THE engine): the script's vm context moves inside
the worker, agent() bridges to ctx.subagents over the message port
(host.ts/protocol.ts/session.ts/worker.ts are new; runtime.ts loses the
abandon channel — the host's grace timer force-settles and TERMINATES
instead), start() pre-parses the body host-side to keep the seam's
synchronous SCRIPT_PARSE throw, and a ready→go handshake keeps a run
cancelled before start from ever executing the body. start() no longer
blocks the host, termination is real, and the value boundary is
serialization by construction. The package keeps its name until the
follow-up rename commit; scripts see the identical hook surface, and
the seam-contract tests hardened ahead of this swap pass unchanged.
The run and child-RPC surfaces are class-shaped rather than literal
bundles: WorkerRun IMPLEMENTS the seam's WorkflowRun (id/meta are its
own clone, separate from event payloads') and start() returns the
instance directly — interface parity with the seam is compiler-checked;
worker-side, ChildRpcBridge (implements ChildPort; callId allocation +
pending book-keeping settled by onChild* entry points) and
RpcChildHandle (every member an RPC keyed by its callId) carry names in
stacks. ChildPort's method is startAgent — it names what it starts,
matching the script-side agent() hook and the agentsStarted /
workflow/agent-* vocabulary; the Child* type names deliberately stay
(the worker side is cordis- and subagent-free; these are reduced JSON
projections, not the seam's types).
Review findings from the reference PR are folded in rather than
re-introduced:
- cancel() drives BOTH child-cancel channels host-side: the request
signal aborts AND each registered child's explicit cancel() is
called — a worker wedged in a synchronous spin cannot relay its own
ChildCancel RPCs (regression: cancel-only provider + wedged worker).
- All host warn paths render through the total renderThrown; a child
dispose() rejecting a value whose coercion throws still acks
ChildDisposed instead of wedging the script's finally (regression).
- built-worker.e2e.ts is wired into builtBinSmokeGate and the AGENTS.md
CI sequence — the built lib/worker.js resolution contract now runs in
an automated gate.
- workflow/end payload pinned on the worker-death path (with the
cancelled and grace-force-settle pins riding the ported spec).
- Real-Worker scripted timing budgets widened (50-300ms → 150-1000ms)
for starved CI hosts.
Workspace plumbing: the "./worker" subpath export sanctions the second
runtime bundle (check-workspace-constraints), tsdown builds two
single-entry passes, tsx becomes a devDependency for the unbuilt worker
spawn.
Three engine-agnostic pins, landed BEFORE the worker-thread port so the
port commit demonstrates contract preservation against them:
- tool-workflow: the tool:<toolName> prompt-section registration was
entirely unasserted — assemble() now pins the section present under
the CONFIGURED name and gone after fiber dispose (the packages
AGENTS.md dispose-and-assert-cleanup rule; tool-bash is the template).
- tool-workflow: drop the dead `??` re-defaulting of already-
schemastery-resolved config (the hidden-fallback shape AGENTS.md
bans) and the direct-apply test that existed only to cover those
branches; both engines' `config as ResolvedConfig` is the pattern.
- workflow-vm: workflow/end was asserted only on completed runs — the
cancelled path and the grace force-settle path now pin the event and
its stopReason/error/agentsStarted payload (an observer's only death
signal on those paths).
Beyond the mechanical conflicts (provider capability lines vs master's new
inheritsParentContext field; generated catalogs regenerated rather than
hand-merged; knip/lockfile), three master-side reworks required semantic
adaptation of this branch:
- The persona rework removed AgentOptions.systemPrompt, which was the
structured-output instruction's channel. The instruction now rides the
SAME final-request enforcement listener that injects the schema'd tool:
appended per request to final.system (per-request wire state, not agent
prompt state). Tests assert the wire request (adapter.requests) instead
of child.options; the bare-direct-dispatch test pins the no-system arm.
- Tool guidance moved out of deployment prompts into per-tool prompt
sections; the examples' workflow paragraph became a tool:<toolName>
section contributed by dsh-tool-workflow (explicit-ask-only policy),
and both example personas resolve to master's minimal identity+behavior
form. tool-workflow gains inject: systemPrompt (+ peer dep, tsconfig
ref); the export-shape guard updated.
- The uniform-RFC-format gate: the dynamic-workflows RFC restructured to
the implemented/ skeleton (bare Status line; Proposal -> Decision;
What-was-rejected -> Alternatives considered; new Consequences), and
the overall-run-timeout deferral is now recorded in the RFC's Deferred
list. The doc-graphs atlas classification gains the workflows seam
(workflow-vm implementation, tool-workflow consumer).
Master's harness-identity section made "empty assembled prompt" states
unreachable through the loop, so the instruction-append is a plain
undefined-ternary and the structured tests assert append-not-replace.
All snapshot goldens (including workflow-run) replay unchanged. Full
local CI-equivalent gate sequence green on the merged tree.
Two review responses that belong together — the same review argued the
engine was defending the wrong threat while a benign-input bug wedged
the product.
1) Drop hostile-value containment; state the trust premise.
Scripts are model-written — the same trust level as the model's bash
access — yet successive pre-push review rounds had ratcheted in defenses
that only matter against an adversarial author: trap-free proxy
rejection, accessor-never-invoked descriptor walks, realm-side
pre-rendering of thrown values, realm-built promises/arrays/error clones
with structural fatal recognition. That same author keeps a documented,
accepted, unkillable event-loop spin, so containing its error VALUES is
cost without a threat model — and the planned hardened engine
(worker/isolated-vm) gets value isolation by serialization and deletes
all of this machinery anyway.
What stays, because benign scripts hit it constantly: result never
rejects; dropped hook promises cannot become unhandled rejections; the
value boundary rejects LOUD everything JSON cannot carry (now a plain
recursive walk — getters are read ordinarily and their result is what
crosses; a throwing read fails loud); a "__proto__" key still copies as
a data property; the fatal-vs-null combinator discipline (now host
instanceof — unforgeable from the realm and simpler than clone-shape
recognition). What changes for scripts (documented in the engine
README): hooks hand back host values and host errors — in-script
`instanceof Error` on a hook failure is false (branch on e.name/e.code)
— and args are host-cloned once so a script cannot mutate the caller's
object. realm.ts drops 289 → 173 lines; the hostile-value test tables go
with it. The premise now leads the engine module doc, the README, and
the RFC's engine section, with the removed machinery recorded under
What was rejected.
2) result settles within the dispose grace of a cancellation.
Review finding (verified through the real registry + tool + engine): a
script parked on a promise no hook owns — `await new Promise(() => {})`,
`await Promise.race([])`, a returned never-settling thenable — could not
be settled by cancel(): hooks reject and children abort, but nothing
touches a promise the engine does not own, so `result` stayed pending
FOREVER (the previous cut even pinned that as intended). The tool awaits
run.result BEFORE its disposing finally, the registry awaits the tool,
the loop awaits the registry — one such script wedged the whole agent
turn past any abort, unrecoverable in-process; the mock engine in the
tool's abort test settles result on cancel, which is exactly the
behavior the real engine lacked, so no existing test could see it.
The seam contract now says it out loud: once a run is cancelled, result
SETTLES within the implementation's bounded grace even if the script
never does. The vm engine arms an abandon channel in cancel(); drive()
races the script against it, force-settling 'cancelled' at the grace
(the abandoned settlement stays contained; a post-slice synchronous spin
remains the documented limitation). dispose()'s outer race now exists
for child quiescence only, and `workflow/end` again fires exactly once
per started run. The old 'result stays pending' pin is FLIPPED to the
new contract (the pinned behavior was the bug); new regressions cover
cancel-then-settle on a parked script, a never-settling returned
thenable, and the full composition through the REAL registry + tool +
vm engine (tool-workflow gains workflow-vm/subagent devDeps for it).
agentsStarted JSDoc clarified while touching the vocabulary (accepted
calls, including ones still queued at cancellation).
A new capability family at packages/workflow/ in the bash seam shape,
modeled on Claude Code's dynamic workflows: the model writes a JavaScript
orchestration script (export const meta = {...} + plain-JS body), a runtime
executes it, and the script — not the conversation — holds the loop, the
branching, and the intermediate results.
- dsh-workflow (ctx.workflows): abstract WorkflowService + run vocabulary
(WorkflowRun whose result NEVER rejects) + observe-only workflow/* events
carrying data snapshots (id + meta, never the live run), per-listener
contained like subagent/*.
- dsh-workflow-vm: in-process node:vm engine. Meta extraction via a
string/comment-aware scanner (template interpolation rejected; literal
evaluated alone in an empty timed context; statement blanked line-
preservingly so stacks keep script line numbers). Hooks: agent(prompt,
{label, phase, schema, model}) over ctx.subagents, parallel(), pipeline()
(no cross-stage barrier), phase(), log(), args. Fatal-vs-null discipline:
hook misuse (unknown/deferred options, bad arguments, unsupported
schemas, tripped caps, seam start failures, cancellation) throws fatal
WorkflowErrors the combinators RE-THROW — never dissolved into the
per-item null reserved for child failures. Realm boundary: inbound values
materialized by descriptor walks that never invoke accessors (defineProperty
copies, __proto__-safe); outbound values rebuilt in-realm via the
context's own JSON.parse. Determinism bans (Date.now/Math.random/argless
new Date) kept so future resume support cannot break scripts. Caps and
timeouts are validated Config. Every hook promise carries a no-op
rejection consumer (app-boot exits on unhandled rejections).
- dsh-tool-workflow: the model-facing workflow tool, synchronous like
dsh-tool-subagent (start → await → try/finally dispose; abort bridged;
non-completed → isError). Generic render card titled by a textual
meta.name sniff. The tool description carries the authoring contract.
Wired into examples/{coding-agent,acp-agent} with explicit-ask-only
guidance. Coverage at every tier: unit (meta scanner, materializer incl.
counting-getter and __proto__ regressions, combinator semantics,
concurrency ceiling, caps, cancellation, no-unhandled-rejection abandon),
integration over the real spawn stack, with-key e2e (real two-phase run +
the tool through the registry pipeline), and a recorded ACP snapshot
scenario (workflow-run, 1 child session). RFC:
docs/rfc/implemented/feature/2026-07-05-dynamic-workflows.md (deferred
work explicitly listed). AGENTS.md budget 1575 → 1590 for the new group's
layout line.
Tianyi Cui
imccyu