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LangStitch Documentation

Dev run events

LangStitch documentation

Dev run events¶

When debugging locally, enable the RunEvent SSE stream so LangTailor (or any dev client) can visualize graph execution. RunEvents are development-only — the endpoint is not mounted unless explicitly enabled.

Enable locally¶

export LANGSTITCH_DEV_EVENTS=1
export LANGSTITCH_API_KEY=dev
langstitch run
# GET /runs/{run_id}/events  (localhost SSE; per-run seq numbers)

LangTailor's Build and Run commands set these variables automatically in the integrated terminal when using the SDK compiler path.

Production posture¶

Do not set LANGSTITCH_DEV_EVENTS in production. When dev events are off, invoke paths avoid extra JSON-safe serialization work.