LangChain Debug Bundle (Python)

Overview

An on-call engineer pages you at 2am: the production agent loops, ToolMessage outputs are empty strings, the user sees "I could not find the answer." Someone asks the right question — what state was the graph in when it gave up? — and there is no answer, because the terminal that caught the failure is already gone, the Kubernetes pod has restarted, and the LangSmith URL was never recorded.

This skill produces one artifact: a single bundle-<incident_id>.tar.gz (typically 1-10 MB) containing everything a second engineer needs to reproduce the failure without a live terminal — environment and version manifest, filtered astream_events(version="v2") JSONL, a propagating callback stack, the LangSmith trace URL, and a post-write sanitization pass.

Four pitfalls make naive bundles useless: