fix(sdk): show interrupts raised after a passive thread rejoin by eliornl · Pull Request #2813 · langchain-ai/langgraphjs

Elior Nataf Lackritz (eliornl) · 2026-09-09T15:36:49Z

Summary

Fixes LG-661. After a page refresh (or a second tab) while a run is in progress, an interrupt the run then raises never shows up in useStream until the next reload. isLoading still drops to false, so the agent looks stuck. Reproduced on a real server with a slow-then-interrupt graph: the original tab shows the interrupt, the refreshed tab shows interrupts: [].

Why it happens

After hydrate, the controller treats every input.requested it does not already know from state.tasks[].interrupts as replayed history, because the SSE replays the whole thread buffer on connect and the stream has no marker for where replay ends. #2807 parks those unknown interrupts until a checkpoints event carrying the hydrated checkpoint id arrives, then releases everything newer.

That event never arrives:

LangGraph Python emits the checkpoints stream mode as a get_state()-shaped snapshot. The server session only forwards a checkpoint envelope with a top-level string id, so nothing is forwarded. Zero checkpoints events on the wire in the reproduction, matching the customer's HAR.
LangGraph.js has no checkpoints emission at all (libs/langgraph/src).
The Redis replay buffer trims by age (120s), so on a long node the matching event is gone before the refresh even when it did exist.

So the parked interrupts wait forever.

The fix

Decide parked interrupts with the server's thread state instead of a stream marker.

Unknown interrupts are parked as before, now whether or not hydrate returned a checkpoint id (the release no longer needs it).
When a root terminal lifecycle (interrupted / completed / failed) arrives with interrupts parked, #settleParkedInterrupts runs the existing #reconcilePendingInterruptsFromServer: ids the server lists as pending are shown, the rest are dropped as history. Payloads come from state.tasks[].interrupts, the same source hydrate uses, so a refreshed tab and a fresh load agree by construction.
The server commits the interrupt to thread state slightly after it streams the event (the server has its own 5s settle poll for this), so the fetch retries every 500ms for up to 5s. One loop runs at a time, so a replay burst with many old terminals costs one loop, not one per event. The common path (no parked interrupts) makes no extra calls.
Rebased on revert(sdk): appropriately track persisted seq for stream replay (#2807) #2814, which reverts the checkpoints barrier from fix(sdk): appropriately track persisted seq for stream replay #2807. This PR carries the parking list itself; the barrier is gone, so the settle against server state is the only release path.

Tests

controller.test.ts:

shows an interrupt raised after a passive rejoin without a checkpoints event
waits for the server to commit the interrupt before showing it (second fetch returns it)
drops replayed interrupts the server no longer lists

All three fail on main. The two #2807 tests still pass. Full libs/sdk unit suite (794) and libs/sdk-react browser suite (244) pass.

Real-stack check (langgraph-api inmem, langgraph 1.2.6): submit a run, create a second StreamController on the same thread 1s in, let the run interrupt at 4s. Before: refreshed tab interrupts: []. After: refreshed tab shows the interrupt, respond() from that tab resumes the run, and it completes.

Follow-ups (not in this PR)

The checkpoints channel is dead on the wire for every current deployment; the server never forwards it because no runtime produces the {id, parent_id, step, source} envelope.
onCompleted not firing after a refresh (also reported in the thread): #runLifecycleListener requires isLoading to be true, and the buffer's running event is trimmed on long runs.

Changeset: @langchain/langgraph-sdk patch.

changeset-bot · 2026-09-09T15:36:56Z

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Latest commit: 105ba45

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 5 packages

Name	Type
@langchain/langgraph-sdk	Patch
@langchain/angular	Patch
@langchain/react	Patch
@langchain/svelte	Patch
@langchain/vue	Patch

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commit: 105ba45

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Open SWE Review found 1 potential issue.

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After a page refresh mid-run, the controller treated every input.requested it did not already know from the hydrated thread state as replayed history and dropped it. The SSE replays the thread buffer on connect with no marker for where the replay ends, so the interrupt the run then raised never reached the UI until the next reload, while isLoading still dropped to false. Unknown interrupts are now parked, and settled against the server's thread state when a root terminal lifecycle arrives: ids the server lists in tasks[].interrupts are shown, the rest are dropped as history. The state is written slightly after the event streams, so the fetch retries every 500ms for up to 5s, coalesced across a replay burst. A failed fetch keeps retrying until the deadline; only disposal, a thread swap, or a new submit stop the loop.

@eliornl

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⚠️ # Releases ## @langchain/langgraph-sdk@1.10.3-rc.2 ### Patch Changes - [#2813](#2813) [`4fc118f`](4fc118f) Thanks [@eliornl](https://github.com/eliornl)! - fix(sdk): show interrupts raised after a passive thread rejoin After a page refresh mid-run, `useStream` filtered every interrupt it did not already know from the hydrated thread state as replayed history, and waited for a `checkpoints` event to lift that filter. Current runtimes never emit that event and the replay buffer trims it on long runs, so interrupts raised after the refresh never appeared until the next reload. Unknown interrupts are now settled against the server's thread state when the run reaches a terminal lifecycle: the ones the server lists as pending are shown, the rest are dropped as history. - [#2812](#2812) [`db4bdad`](db4bdad) Thanks [@eliornl](https://github.com/eliornl)! - fix(sdk): recover from a server-side thread stream drop instead of freezing The protocol SSE transport now reconnects when the server closes the event stream cleanly. The thread stream is open-ended, so a clean close only happens when the server's own upstream consumer died or it is restarting; before, the client treated it as the end of the thread and the UI froze mid-run with no error. A connection that delivered events also resets the reconnect budget, so long-lived pages survive repeated deploys. `maxReconnectAttempts: 0` keeps the old end-on-close behavior. Unsolicited server error frames (no command id) and a shared stream that gives up reconnecting now reach `stream.error`: `ThreadStream.onError` exposes them, `useStream` sets `error`, clears `isLoading`, and settles the in-flight `submit()` as failed. ## @langchain/angular@1.0.36-rc.2 ### Patch Changes - Updated dependencies [[`4fc118f`](4fc118f), [`db4bdad`](db4bdad)]: - @langchain/langgraph-sdk@1.10.3-rc.2 ## @langchain/react@1.0.36-rc.2 ### Patch Changes - Updated dependencies [[`4fc118f`](4fc118f), [`db4bdad`](db4bdad)]: - @langchain/langgraph-sdk@1.10.3-rc.2 ## @langchain/svelte@1.0.36-rc.2 ### Patch Changes - Updated dependencies [[`4fc118f`](4fc118f), [`db4bdad`](db4bdad)]: - @langchain/langgraph-sdk@1.10.3-rc.2 ## @langchain/vue@1.0.36-rc.2 ### Patch Changes - Updated dependencies [[`4fc118f`](4fc118f), [`db4bdad`](db4bdad)]: - @langchain/langgraph-sdk@1.10.3-rc.2 Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

@ramon-langchain

This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## @langchain/langgraph-sdk@1.11.0 ### Minor Changes - [#2831](#2831) [`3234c69`](3234c69) Thanks [@ramon-langchain](https://github.com/ramon-langchain)! - Expose connection lifecycle callbacks for built-in streaming transports. `onConnected` runs after the initial SSE or WebSocket connection becomes usable and after every successful reconnect. Its payload distinguishes an `initial` connection from a `reconnected` connection and includes the reconnect attempt number. `onReconnect` now also receives the scheduled `delayMs`, allowing applications to display accurate retry state before the next connection attempt. React, Vue, Svelte, and Angular stream hooks forward both callbacks. ### Patch Changes - [#2831](#2831) [`3234c69`](3234c69) Thanks [@ramon-langchain](https://github.com/ramon-langchain)! - Recover cleanly when a thread's root event stream terminates unexpectedly. If the stream fails or closes while a run is active, the controller now records the transport error and clears `isLoading` rather than leaving the UI in a permanently running state. Once the failed pump settles, a later submission can start a fresh root subscription without recreating the thread stream or replaying the failed command. - [#2809](#2809) [`11a4535`](11a4535) Thanks [@hntrl](https://github.com/hntrl)! - fix(sdk): appropriately track persisted seq for stream replay Sequences weren't being appropriately attributed when rehydrating the page (e.g. on refresh). This meant we'd lose stream information on `useStream` on reloads. This has been fixed by adding a lookup step to determine what the most appropriate sequence index is to track in the event stream.:x - [#2762](#2762) [`2fab6fd`](2fab6fd) Thanks [@JessYanCoding](https://github.com/JessYanCoding)! - Send `checkpoint_id` in the `runs.stream()` request body, so a `checkpointId` passed to `client.runs.stream()` forks from the requested checkpoint instead of being silently dropped. Matches `runs.create()` and `runs.wait()`, which already send it. - [#2813](#2813) [`4fc118f`](4fc118f) Thanks [@eliornl](https://github.com/eliornl)! - fix(sdk): show interrupts raised after a passive thread rejoin After a page refresh mid-run, `useStream` filtered every interrupt it did not already know from the hydrated thread state as replayed history, and waited for a `checkpoints` event to lift that filter. Current runtimes never emit that event and the replay buffer trims it on long runs, so interrupts raised after the refresh never appeared until the next reload. Unknown interrupts are now settled against the server's thread state when the run reaches a terminal lifecycle: the ones the server lists as pending are shown, the rest are dropped as history. - [#2812](#2812) [`db4bdad`](db4bdad) Thanks [@eliornl](https://github.com/eliornl)! - fix(sdk): recover from a server-side thread stream drop instead of freezing The protocol SSE transport now reconnects when the server closes the event stream cleanly. The thread stream is open-ended, so a clean close only happens when the server's own upstream consumer died or it is restarting; before, the client treated it as the end of the thread and the UI froze mid-run with no error. A connection that delivered events also resets the reconnect budget, so long-lived pages survive repeated deploys. `maxReconnectAttempts: 0` keeps the old end-on-close behavior. Unsolicited server error frames (no command id) and a shared stream that gives up reconnecting now reach `stream.error`: `ThreadStream.onError` exposes them, `useStream` sets `error`, clears `isLoading`, and settles the in-flight `submit()` as failed. - [#2808](#2808) [`55fa26b`](55fa26b) Thanks [@hntrl](https://github.com/hntrl)! - fix(sdk): coalesce locally resolved interrupts when resolving interrupts using `useStream`, there was a case where we prioritized the remote state values (which we lookup in React Strict mode on every page transition) over the local interrupt responses we know we've responded with. This has since been fixed to first prioritize the local cache of interrupts, resolved against the remote state values when a run hits a terminal event ## @langchain/angular@1.1.0 ### Minor Changes - [#2831](#2831) [`3234c69`](3234c69) Thanks [@ramon-langchain](https://github.com/ramon-langchain)! - Expose connection lifecycle callbacks for built-in streaming transports. `onConnected` runs after the initial SSE or WebSocket connection becomes usable and after every successful reconnect. Its payload distinguishes an `initial` connection from a `reconnected` connection and includes the reconnect attempt number. `onReconnect` now also receives the scheduled `delayMs`, allowing applications to display accurate retry state before the next connection attempt. React, Vue, Svelte, and Angular stream hooks forward both callbacks. ### Patch Changes - Updated dependencies [[`3234c69`](3234c69), [`3234c69`](3234c69), [`11a4535`](11a4535), [`2fab6fd`](2fab6fd), [`4fc118f`](4fc118f), [`db4bdad`](db4bdad), [`55fa26b`](55fa26b)]: - @langchain/langgraph-sdk@1.11.0 ## @langchain/react@1.1.0 ### Minor Changes - [#2831](#2831) [`3234c69`](3234c69) Thanks [@ramon-langchain](https://github.com/ramon-langchain)! - Expose connection lifecycle callbacks for built-in streaming transports. `onConnected` runs after the initial SSE or WebSocket connection becomes usable and after every successful reconnect. Its payload distinguishes an `initial` connection from a `reconnected` connection and includes the reconnect attempt number. `onReconnect` now also receives the scheduled `delayMs`, allowing applications to display accurate retry state before the next connection attempt. React, Vue, Svelte, and Angular stream hooks forward both callbacks. ### Patch Changes - Updated dependencies [[`3234c69`](3234c69), [`3234c69`](3234c69), [`11a4535`](11a4535), [`2fab6fd`](2fab6fd), [`4fc118f`](4fc118f), [`db4bdad`](db4bdad), [`55fa26b`](55fa26b)]: - @langchain/langgraph-sdk@1.11.0 ## @langchain/svelte@1.1.0 ### Minor Changes - [#2831](#2831) [`3234c69`](3234c69) Thanks [@ramon-langchain](https://github.com/ramon-langchain)! - Expose connection lifecycle callbacks for built-in streaming transports. `onConnected` runs after the initial SSE or WebSocket connection becomes usable and after every successful reconnect. Its payload distinguishes an `initial` connection from a `reconnected` connection and includes the reconnect attempt number. `onReconnect` now also receives the scheduled `delayMs`, allowing applications to display accurate retry state before the next connection attempt. React, Vue, Svelte, and Angular stream hooks forward both callbacks. ### Patch Changes - Updated dependencies [[`3234c69`](3234c69), [`3234c69`](3234c69), [`11a4535`](11a4535), [`2fab6fd`](2fab6fd), [`4fc118f`](4fc118f), [`db4bdad`](db4bdad), [`55fa26b`](55fa26b)]: - @langchain/langgraph-sdk@1.11.0 ## @langchain/vue@1.1.0 ### Minor Changes - [#2831](#2831) [`3234c69`](3234c69) Thanks [@ramon-langchain](https://github.com/ramon-langchain)! - Expose connection lifecycle callbacks for built-in streaming transports. `onConnected` runs after the initial SSE or WebSocket connection becomes usable and after every successful reconnect. Its payload distinguishes an `initial` connection from a `reconnected` connection and includes the reconnect attempt number. `onReconnect` now also receives the scheduled `delayMs`, allowing applications to display accurate retry state before the next connection attempt. React, Vue, Svelte, and Angular stream hooks forward both callbacks. ### Patch Changes - Updated dependencies [[`3234c69`](3234c69), [`3234c69`](3234c69), [`11a4535`](11a4535), [`2fab6fd`](2fab6fd), [`4fc118f`](4fc118f), [`db4bdad`](db4bdad), [`55fa26b`](55fa26b)]: - @langchain/langgraph-sdk@1.11.0 ## @langchain/langgraph-api@1.4.6 ### Patch Changes - [#2751](#2751) [`0a9611a`](0a9611a) Thanks [@t3s7r](https://github.com/t3s7r)! - fix(api): `run.start` with input on a cancelled thread no longer folds the input into `Command(resume)`. A cancelled run shares the "interrupted" status with a genuine `interrupt()` pause, but has no pending interrupt to consume the resume value, so the submitted message was silently dropped. The input-vs-resume decision now keys on whether the thread actually has pending interrupts (both in the protocol service and the embed protocol). - Updated dependencies []: - @langchain/langgraph-ui@1.4.6 ## @langchain/langgraph-cli@1.4.6 ### Patch Changes - Updated dependencies [[`0a9611a`](0a9611a)]: - @langchain/langgraph-api@1.4.6 ## @langchain/langgraph@1.4.15 ### Patch Changes - [#2794](#2794) [`83a4b62`](83a4b62) Thanks [@hntrl](https://github.com/hntrl)! - feat(langgraph): add per-node `tracePolicy` input/output processors and `omitPayload` Transform the payloads recorded on a node's own trace run while retaining its span and timing. Processors receive raw values and fall back to the original payload if they throw. Graph state, root runs, and child runs remain unchanged when processors do not mutate their arguments. Matches Python's callback-level behavior: transforms also affect chain events and message streaming, so omitting outputs can suppress messages returned directly by nodes and omitting inputs can affect message deduplication. - Updated dependencies [[`3234c69`](3234c69), [`3234c69`](3234c69), [`11a4535`](11a4535), [`2fab6fd`](2fab6fd), [`4fc118f`](4fc118f), [`db4bdad`](db4bdad), [`55fa26b`](55fa26b)]: - @langchain/langgraph-sdk@1.11.0 ## @langchain/langgraph-cua@1.0.3 No changes in this release. ## @langchain/langgraph-supervisor@1.1.2 No changes in this release. ## @langchain/langgraph-swarm@1.0.3 No changes in this release. ## @langchain/langgraph-ui@1.4.6 No changes in this release. Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

open-swe Bot reviewed Sep 9, 2026

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Elior Nataf Lackritz (eliornl) and others added 3 commits September 9, 2026 13:22

chore(sdk): use promise class member to track settle routine

dcc202a

chore(sdk): format settle routine

105ba45

Elior Nataf Lackritz (eliornl) force-pushed the fix/sdk-passive-rejoin-interrupts branch from eb79e73 to 105ba45 Compare September 9, 2026 17:24

Hunter Lovell (hntrl) approved these changes Sep 9, 2026

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Elior Nataf Lackritz (eliornl) merged commit 4fc118f into main Sep 9, 2026
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Elior Nataf Lackritz (eliornl) deleted the fix/sdk-passive-rejoin-interrupts branch September 9, 2026 17:38

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chore: version packages (rc) #2816

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chore: version packages mexicanamerican/langgraphjs#17

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chore: version packages #2832

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chore: version packages praxstack/langchain-ai-langgraphjs#2

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Rahul Raj Purohit (rrajpuro) mentioned this pull request Sep 16, 2026

SDK v2: hydrated interrupt stays pending after another client resumes the thread #2842

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fix(sdk): show interrupts raised after a passive thread rejoin - #2813

fix(sdk): show interrupts raised after a passive thread rejoin#2813
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