new·The score now tells you which way it movedA brain's exam only ever grows: its own material writes questions, and so does every question a real caller asked and did not get answered. The score is a percentage over that growing set, so a brain that learned more could post a smaller number — and this week three did. One of them answered two MORE questions than the week before and showed eighteen points less. Printed as a single percentage, that reads as decline to a reader and as punishment to anyone who contributes material.all news →
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LangChain · LangGraph · all subjects

error handling & fault tolerance

9 notes, read out of this brain and free to use. Each one was extracted from a source and is re-checked against its exam.

Send.timeout serialization rejection in gRPC

v0.13 rejects Send.timeout in gRPC serialization to prevent silent loss of per-task timeout semantics. This ensures that timeout configurations in tool routing are properly validated and not silently ignored.

Cancelled runs retry prevention fix

v0.13 fixes a bug where cancelled runs could be retried if the worker died before acknowledging the cancellation. This ensures cancellation acknowledgment is properly persisted before a run can be retried.

Null bytes replaced with U+FFFD replacement character

Null bytes are replaced with U+FFFD in all handling paths to prevent key collisions in store operations.

Structured error payloads in webhooks

Webhook error payloads now include `error` and `message` fields in a structured format, replacing the previous flat string format. This may affect systems parsing the `error` field.

Error message sanitization in streams

Error messages in streams and A2A responses are sanitized to protect sensitive information like database connection strings and internal hostnames.

Deserialization vulnerability fix in langgraph-checkpoint

Agent-server v0.5.0+ requires langgraph-checkpoint versions later than 3.0 to prevent a deserialization vulnerability in earlier versions. The langgraph-checkpoint library is compatible with langgraph minor versions 0.4, 0.5, 0.6, and 1.0.

Run stream event duplicate handling with race condition fix

Race condition handling for run streaming was ensured by fully subscribing before execution starts, with added support for the `FF_LOG_DROPPED_EVENTS` environment variable to track dropped events.

Reserved metadata keys stripped from request payloads

Reserved metadata keys in request payloads are now silently stripped rather than causing a 422 error, enhancing user experience and preventing validation failures.

A2A validation checks for message format

A2A validation checks were added in `message/stream` and `message/send` routes for `parts`, `role`, and `messageId` fields to ensure proper message format compliance.

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