Does Tessary need access to my repo to find the root cause?

Not strictly: RCA still runs and completes on trace evidence alone when no repo is connected, it just says so and reports a lower ceiling on what it can conclude. With a repo linked, it reads the code alongside the trace evidence to work backward through what actually changed, and the resulting report can name the specific files behind a hypothesis. Without one, it stays at the trace level: no files to cite, hypotheses about behavior rather than about a specific code change. If you want the fuller report, connecting the repo is what buys it. Skipping that step doesn’t block an investigation, it just caps what the investigation can tell you.