Use plan-validate-execute with a verifiable intermediate file for any batch or destructive agent operation

Claude Docs·medium signal

For multi-item changes (e.g., updating 50 fields from a spreadsheet), have the agent first emit a structured plan file (changes.json), run a verbose validation script against it, and only then execute — turning silent mistakes into machine-checkable errors caught before anything is mutated. Make validators verbose ('Field signature_date not found. Available: …') so the agent can self-correct in a loop. This pattern makes open-ended agent work reversible and debuggable.