debugging-and-error-recovery

Guides systematic root-cause debugging and recovery instead of guessing fixes. Use when tests fail, builds break, commands error, logs or consoles show errors, runtime behavior differs from expectation, a bug is reported, a prior fix did not work, CI/deploy/smoke checks fail, or something worked before and stopped working. Also use when Codex encounters an unexpected tool, package, API, network, infrastructure, or vendor error during a task.