LibreChat/packages/data-provider
Danny Avila d174d1a023 🛑 feat: Preemptive Steer — server half (Interrupt & Steer, PR 2 of 3)
Lets the steer route ask the generating replica to seal its live model
stream at the next provider-safe boundary instead of waiting for a tool
step. The run is never aborted, job status never changes, the partial
answer is kept, and generation resumes in the same assistant message
after the injected steer. Consumes the SDK seam in @librechat/agents
(danny-avila/agents#335, #346).

Transport: IEventTransport gains a fenced emitPreempt/onPreempt pair
beside abort. RedisEventTransport fans PREEMPT out on the SAME events
channel and subscription (no new connection, key, or subscribe call);
onPreempt returns a registration-scoped unsubscribe with the same
replacement-safe state-identity guard onAbort uses. InMemory implements
neither — single-process preempt lives entirely in the runtime set.

Runtime state: RuntimeJobState carries the per-generation request set,
createdAt-fenced and capped at STEER_QUEUE_MAX_DEPTH, plus a bounded
`cleared` tombstone so a late cross-replica arm cannot resurrect a
request whose steer already drained. registerPreemptSubscription
mirrors the abort registration's double fence (runtime identity +
generation createdAt); releaseAbortSubscription retires BOTH listeners
and the armed set, so every terminal path drops preempt state for free.
Public surface: requestPreempt (arm + fenced publish, never a rejection
surface, never touches job status), isPreemptRequested (O(1)
level-triggered poll), noteSteersRemoved (drain/cancel bookkeeping +
fenced clear), clearPreemptRequests (empty-boundary disarm).

One drain body, two boundaries: createSteerDrainHook (PostToolBatch)
and createSteerPreemptBoundaryHook (PreemptBoundary) share
drainAndBuildInjections, so the two injection sites cannot drift — the
SDK's provider-safety argument rests on identical HumanMessage shapes.
The shared body builds injections incrementally under a swallow-all
catch (a mid-loop throw still injects what was applied — those parts
are already persisted), clears preempt requests in finally, and
disarms the generation when a boundary drains nothing.

Request path: POST /chat/steer accepts preempt: true. The guard ladder
is unchanged in order and in every status code. A preempt request is
NEVER a rejection reason — without the capability the steer still
enqueues and the 202 echoes preempt: false. Armed strictly after a
successful enqueue; cancel disarms. The capability is read from the
OWNING replica's recorded `preemptCapable` rather than the route
replica's own SDK probe, so a rolling deploy cannot label a steer
"interrupting" that the older owner will only inject at a tool step.

Durable label: SteerQueueItem.preempt → TPendingSteer.preempt, so a
parked/claimed/replayed chip keeps its wording.

Run wiring: createRun registers the PreemptBoundary hook and threads
RunConfig.preemption, both gated on isSteerPreemptSupported() — a
separate probe from isSteeringSupported(), so the client affordance can
never arm against an SDK that only injects at tool boundaries.
buildSteerWiring builds both hooks from one shared closures object, so
preemption survives HITL pause/resume for free.

Honest finalization: an empty preempt boundary persists and emits with
unfinished: true — the same contract an abort gets — re-marked
explicitly because BaseClient has already saved the row as
unfinished: false by that point.

Not changed: no new job status, store method, Lua, SSE event type,
endpoint, or authorization surface. abortJob, completeJob,
transitionStatus, closeAndDrainSteers, getResumeState, emitChunk,
applySteerPart and the whole abort path are untouched.

Tests: 120 packages/api steering specs (preempt lifecycle, tombstone,
fences, caps, terminal release, both-boundary drain parity,
level-triggered poll, request/cancel arming, owner-capability
degradation) plus 5 in api for buildSteerWiring gating, and 2
Redis-gated cross-replica transport specs.
2026-07-30 08:28:14 -04:00
..
react-query 📦 chore: bump @librechat/agents to v3.2.42 (#13848) 2026-06-19 09:47:46 -04:00
specs 🪢 feat: Langfuse Fanout Connection Setting (#14108) 2026-07-29 18:33:10 -04:00
src 🛑 feat: Preemptive Steer — server half (Interrupt & Steer, PR 2 of 3) 2026-07-30 08:28:14 -04:00
.gitignore
babel.config.js
check_updates.sh
jest.config.js
package.json 🍂 chore: Prune Deprecated Packages From the Dependency Tree (#14483) 2026-07-28 09:28:06 -04:00
server-rollup.config.js
tsconfig.build.json refactor: Migrate data-provider Build to tsdown (split tsc dts) (#13597) 2026-06-08 11:09:16 -04:00
tsconfig.json 📦 chore: npm audit fixes and Mongoose 8.23 TypeScript follow-ups (#12996) 2026-05-07 09:47:40 -04:00
tsconfig.spec.json 📦 chore: Update TypeScript Config for TS v7 (#12794) 2026-04-23 12:51:03 -04:00
tsdown.config.mjs 🪟 fix: Cross-Platform Absolute-Path Check in tsdown neverBundle Predicates (#13700) 2026-06-13 11:04:46 -04:00