Undertaker tool diagnoses stuck Temporal workflows using a local 4B model

A developer built Undertaker, a tool that scans a Temporal server for running workflows that will never finish. It classifies each stuck workflow into one of nine causes using rules based on Temporal's own data, such as pending activities, history events, and task-queue pollers. The tool then writes a certificate for each one, citing evidence, relevant code lines, and a command to fix or end the workflow. Gemma 4 running locally via Ollama drafts the wording, while plain code makes the diagnosis and verifies every fact the model cites. The author emphasizes local processing because workflow histories can contain sensitive payloads and stack traces that teams may not want to send to hosted models.