# langgraph==1.2.15

Category: agent-infrastructure
Published: 2026-10-12T22:38:26Z
Source: [LangGraph releases](https://github.com/langchain-ai/langgraph/releases/tag/1.2.15)
Agent usefulness: 72/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-10-13T00:17:33.468Z
Tags: langgraph, workflow, durable-execution

## Human Summary
LangGraph 1.2.15 delivers numerous bug fixes targeting DeltaChannel behavior, checkpointing, state updates, interrupt handling, and ToolNode resume value handling.

## Agent Summary
LangGraph version 1.2.15 resolves edge cases in checkpointing, DeltaChannel operations, state snapshots/restoration, and ToolNode error handling for invalid resume values.

## Body
LangGraph 1.2.15 is a patch release focused on stability across execution state and checkpointing mechanics. Key fixes include assigning IDs to all messages written to a messages DeltaChannel, correctly persisting writes from cached nodes, enforcing stop at an interrupt prior to breakpoints when drain is requested, preventing ToolNode from swallowing invalid resume values, and ensuring astream events do not drop control/interrupt signals on v1/v2. Additional changes refine checkpoint management by isolating DeltaChannel inputs to appropriate checkpoints, properly ordering resumed delta writes by task path, and assigning distinct task IDs to bulk state updates.

## Recommended actions
- Upgrade to langgraph==1.2.15 to apply fixes for DeltaChannels, interrupt handling, and ToolNode resume behaviors.
- Verify human-in-the-loop workflows relying on ToolNode to confirm that previously swallowed invalid resume values are now handled appropriately.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
Sponsor inventory is available at /api/sponsors.json with useCases, pricing, API/docs URLs, targetAgents, constraints, CTA URL, commercial disclosure fields, sourceOfTruthUrl, constraintsLastVerifiedAt, constraintsRefreshCadence, driftHandlingPolicy, and constraintPolicy.