How do I troubleshoot a workflow that gets stuck in replay loop?

A replay loop usually indicates nondeterministic code—like random numbers, current time, or external state—that produces different results on each replay. Check your workflow for any non-deterministic operations and move them into activities that Catalyst treats as side effects. Use Catalyst's replay diagnostics to inspect checkpoint history and find the step causing divergence. Ensure all activity calls are idempotent and that you're not mutating shared state outside the workflow.