The app is a self-contained offline HTML file: ../../apps/staged-paths.html. The method note defines the model and claim boundaries.

Exact finite checks

No dependencies beyond Node.js:

node project-co-design/docs/rail-staged-codesign/verify.mjs

This imports model.cjs, the exact engine embedded in the app, and compares it with the independently written all-history oracle.mjs. The command writes results.json beside the checker. Optional arguments replace the engine path and output path. results.json is the retained successful run, including the parameter rows and a temporary-bridge witness.

Browser action checks

Install Playwright and its Chromium browser in your own test environment, serve the repository root on port 8770, then run:

REQUIRE_INDEX=1 node project-co-design/docs/rail-staged-codesign/browser.cjs

Optional environment variables: APP_URL selects another local or deployed page; PLAYWRIGHT_MODULE supplies a Playwright module path; CHROMIUM_PATH selects an installed Chromium browser; QA_DIR changes the temporary result directory. The checked action loops cover valid and invalid inputs, correction, reload, URL sharing, JSON export, the seven worked cases, keyboard selection, responsive layouts, earlier-app return and gallery discovery. browser-results.json records the successful migration test run; the local experiment receipt records the commit, served-file comparisons and retained screenshots.

The application creates no account or server record. Sharing retains the applied brief in a URL. Export downloads a local calculation file. Path selection and replay position are deliberately temporary. No file is overwritten by application controls.