Fail-Fast CLI Catches Silent YAML/JSON Config Drift Before Production Deploys

Configuration drift in large distributed systems often slips past basic linters, since errors like missing fields, mistyped values, or misplaced nested mappings only surface at runtime. To address this, the author built a CLI validator that parses YAML and JSON files and checks them against strict Pydantic v2 schemas inside CI/CD pipelines. The tool selects a parser based on file extension, using orjson for JSON and safe YAML loading for YAML files, and reports all validation errors in a single pass. It returns exit code 0 on success, 2 on schema violations, and 1 for other crashes. During QA testing, the script exited early because the orjson dependency was missing, a failure caused by the environment rather than the code's logic.