Open-Source Vault of 150+ Production Cursor Rules & System Prompts (.mdc)

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1

Hey everyone,

To prevent prompt drift and repetitive instructions across projects, I put together a structured repository of 150+ production-tested rules (.mdc format):

  • SOLID architecture & domain boundaries
  • Hermetic unit testing & edge case verification
  • Framework-specific rules (FastAPI, Next.js, TypeScript)

Everything is open-source under MIT on GitHub:

Feel free to drop any of the rules into your .cursor/rules/ directory or suggest improvements!

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Quick update: we just tagged and published v1.0.0 on GitHub!

Added new .mdc architectural rulesets for:

  • FastAPI async boundary isolation & token rate limiting
  • Next.js 15 App Router & Supabase SSR cookie synchronization
  • Hermetic unit test generators (AAA pattern with zero ambient mocks)

Full changelog and release archive:

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Update: Added an architectural reference and .mdc rule for sub-100ms Edge token streaming with Next.js 15 App Router & Supabase SSR.

Includes:

  • Native ReadableStream SSE streaming route handler
  • Client-side zero-flicker stream reader loop
  • Sliding-window rate limiter to prevent API credit abuse

Available in the repository: AymaneWebDEV/developer-prompt-vault