Configuration drifts quietly. A variable gets renamed in one environment, a default stops matching its type, an old name lingers after the code that read it was deleted — and none of it surfaces until a deploy fails.
This walkthrough uses the tool's public README and checked-in example files. Run the command from a repository checkout with Node.js 22+.
Run the checked-in example
node bin/env-var-contract-checker.mjs \
--contract examples/contract.json \
--env examples/production.env.jsonRead the result
Note the last line: the tool reports that a secret leaked into the manifest without repeating what leaked.