Error Handling

Specific Exceptions

• Catch specific exception types, never bare catch-all handlers
• Let unexpected exceptions propagate — they indicate bugs that need fixing, not hiding

Actionable Messages

• Error messages must tell the user what to do, not just what went wrong
• Bad: "File not found"
• Good: "Config file not found at ~/.config/app.toml — run app init to create one"

Graceful Fallback

• When multiple approaches exist, try alternatives before failing
• Example: try the preferred tool, fall back to an alternative, then fail with a clear message listing what was tried

Structured Logging

• Log at appropriate levels: DEBUG for internals, INFO for progress, WARN for recoverable issues, ERROR for failures
• Include enough context to diagnose without reproducing: input parameters, relevant state, error details
• Never log secrets, tokens, passwords, or credentials — not even at DEBUG level