langgraph-code-review

Review LangGraph code against a checklist covering state mutations, reducers, checkpointing, graph structure, entrypoints, edges, async patterns, and tool integration. This catches common issues like improper state handling, missing checkpointers for interrupts, and incorrect edge wiring that break correctness.

Ensure state uses reducers to prevent mutations, define proper schemas with annotations, and avoid direct state modification. LangGraph requires immutable state handling; violations cause state corruption and unpredictable graph behavior.

Checkpointers are required to enable interrupts and resumable workflows in LangGraph. Without one, your graph cannot pause, resume, or recover from failures, limiting its ability to handle long-running or interactive tasks.

Validate that edges return correct types matching your StateGraph definition and that entrypoints are properly established. Incorrect wiring causes runtime errors and prevents the graph from executing as intended.

Check that async functions are properly awaited, tool calls follow messaging conventions, and tool outputs integrate correctly into state. Misaligned patterns cause execution failures and tool communication breakdowns.