Debug Gdansk

Use this workflow when gdansk is already present but something is broken. Diagnose from the failing boundary outward and prefer exact error strings over speculative fixes.

1) Identify the failing boundary first

Classify the issue before editing:

1. Registration-time failure:
   • Invalid Vite(...) root path.
   • Invalid @ship.widget(path=...) input.
   • Duplicate widget or tool registration.
2. Frontend startup or build failure:
   • Vite runtime never becomes healthy.
   • Production server bundle is missing.
   • Client bundle output is missing.
3. Render or browser runtime failure:
   • Render request returns an execution error.
   • Rendered HTML is invalid or missing scripts.
   • CSS is not emitted or not loaded.

If the repo does not have gdansk wired yet and the task is mainly setup, switch to $use-gdansk.

2) Validate the public contract before changing behavior

Start with structure and contract checks:

• Confirm Vite(...) points at the frontend package root.
• Confirm the frontend package contains package.json, vite.config.ts, and widgets/.
• Confirm the widget file exists at widgets/**/widget.tsx or widget.jsx.
• Confirm @ship.widget(path=...) uses a path relative to widgets/.
• Confirm the widget default-exports the React component.
• Confirm the frontend package declares @gdansk/vite, vite, @vitejs/plugin-react, react, react-dom, and @modelcontextprotocol/ext-apps.

Use path-contract.md for accepted and rejected widget path inputs.

3) Match the failure to the smallest likely fix

• For validation errors, fix the path or duplicate registration directly.
• For build and startup failures, inspect vite.config.ts, package dependencies, and bundle outputs under dist/.
• For runtime host or port issues, keep Vite(Path(...), host=..., port=...) on Ship(vite=...) and gdansk({ host, port }) aligned.
• For build output directory mismatches, keep Vite(Path(...), build_directory=...) and gdansk({ buildDirectory }) aligned.
• For render errors, isolate the widget's default export and runtime-safe imports first.
• For CSS issues, confirm the styles are imported from the widget tree and emitted into the bundle.

Use troubleshooting.md for error-to-fix mapping.

4) Verify after each fix

After each change:

1. Restart the server in development if the runtime configuration changed.
2. Confirm the Vite dev client becomes reachable at @vite/client.
3. Confirm expected bundle outputs exist under dist/.
4. Fetch or open the widget resource and verify the rendered HTML references the expected assets.
5. Re-run the failing user flow instead of assuming the previous error was the only problem.

Guardrails

• Do not rewrite the integration architecture when a path, dependency, or runtime mismatch explains the failure.
• Do not use absolute widget paths or widgets/... prefixes in @ship.widget(...).
• Do not debug by guessing at internal gdansk behavior when the public contract or emitted error already explains the problem.

Reference map

• Widget path contract and ui:// mapping: path-contract.md
• Error-driven diagnosis: troubleshooting.md