principle-make-operations-idempotent

What problem does it solve? Operations that run amid crashes, restarts, and retries often leave partial state behind, turning every restart into a debugging session. This Skill provides a design discipline for making commands, lifecycle steps, and processing loops converge to the same end state regardless of how many times they run or where they start from. ## Core Features & Use Cases - Convergent Startup Pattern: Scan for existing state, clean stale artifacts, and adopt live sessions instead of assuming a clean slate. - Content-Based Cleanup: Compare artifacts by content equivalence rather than creation order to avoid duplicate or orphaned outputs. - Self-Healing Locks and Scheduling: Use PID-based stale lock detection and respawn failed work cleanly with fresh input regenerated after each cycle. - Use Case: When writing a CLI command that installs resources or a worker loop that processes a queue, apply the three-question test (runs twice, crashed midway, converges to same state) to identify where reconciliation steps are needed. ## Quick Start Ask the AI to review your command or processing loop for idempotency using the make-operations-idempotent principle and identify where partial state could break re-runs.