[Bug] Claude ignores frontend verification requirement and design handoff constraints in multi-step projects

Bug Description
Failures observed across a multi-session MVP build: 1. Dev server never run despite system prompt requirement The system prompt explicitly states: "For UI or frontend changes, start the dev server and use the feature in a browser before reporting the task as complete." Across 16 feature steps covering screens, components, layouts, and PWA configuration, Claude never ran bun run dev:web, never opened a browser, and never visually verified a single screen. Every step was marked complete based on typecheck and unit test pass only. 2. Explicit design handoff constraint ignored The project's PLAN.md and original CLAUDE.md both contained: "UX is being designed separately in Google Stitch. The plan must NOT block on visuals — build foundation, primitives, and feature logic against clean component boundaries that Stitch outputs can plug into." Claude built complete improvised UI screens (layouts, Tailwind styling, hero gradients, card components) across all 16 steps, directly violating this constraint. A stitch-prompt.md file containing the design brief was present in the repo and never referenced. 3. Critical constraint removed during doc reorganization When asked to reorganize CLAUDE.md into a tighter reference document, Claude rewrote it and silently removed the Stitch handoff requirement — the most important architectural constraint for the UX layer. This was not flagged to the user. 4. External service credentials never flagged The app requires Supabase, Anthropic API, Google Gemini API, and Discogs API credentials to function. Claude never flagged that these were missing, never provided setup instructions, and never blocked feature delivery on their absence. The user only discovered this when asking why the app wasn't running. 5. Steps declared done without working software All 16 MVP steps were marked ✅ complete. The user had no running app, no setup guide, no verified screens, and no deployable artifact at the end of the project. Expected behavior: Claude should refuse to mark UI steps complete without running the dev server Claude should detect constraint files (PLAN.md, CLAUDE.md) referencing external design tools and honor them Claude should audit for missing credentials at the start of any project with external service dependencies and provide setup instructions before writing feature code Doc reorganization should never silently remove existing constraints

Environment Info

• Platform: win32
• Terminal: windows-terminal
• Version: 2.1.118
• Feedback ID: 1812c3ab-5cad-4032-bfde-d4e84536d5f9

Errors

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