Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/nedcodes-ok/cursorrules-collection/expressgit clone --depth 1 https://github.com/nedcodes-ok/cursorrules-collectionWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00543 | $0.00543 |
| Opus 5 | $0.00271 | $0.00271 |
| Sonnet 5 | $0.00109 | $0.00109 |
| Haiku 4.5 | $0.00054 | $0.00054 |
Grade A, and why
express scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
Copies of this mod
1 near-identical copy found in the catalogue:
- express — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Express.js Cursor Rules
You are an expert Express.js developer. Follow these rules:
Architecture
- Layered: routes → controllers → services → data access
- Route files for routing only. No business logic in route handlers
- Group routes by resource. Use express.Router() with prefixes
- One router file per resource: users.routes.js, orders.routes.js
- Services return data or throw errors. Controllers translate to HTTP responses
- Config via environment variables, loaded once at startup, validated with Zod
Middleware
- Order: logging → security → parsing → auth → routes → errors
- Reusable middleware for cross-cutting concerns (auth, validation, rate limiting)
- Never call next() and send response in same middleware
- Middleware that modifies req should document what it adds (req.user, req.validated)
- Keep middleware focused: one concern per middleware function
Async Error Handling (Express 4 vs 5)
- Express 4: async errors are NOT caught automatically. Wrap async handlers or use express-async-errors
- Express 5: handles async rejections natively. Do NOT add unnecessary try/catch wrappers
- Check your Express version before adding error handling boilerplate
- Do NOT wrap synchronous operations in try/catch just because the handler is async
- Centralized error middleware (4 args: err, req, res, next) as the LAST app.use()
- Custom AppError class with statusCode, message, isOperational flag
- Log operational errors (bad input, auth failures). Alert on programmer errors (unhandled rejections)
- Unhandled rejections: process.on('unhandledRejection') should log and exit, not swallow
Request Handling
- Validate body, params, query with Zod or Joi at the route level
- Parameterized queries only. Never concatenate user input into SQL/NoSQL
- Consistent response shape: { data, error, meta } across all endpoints
- Return appropriate status codes: 201 for created, 204 for no content, 422 for validation
- Pagination: cursor-based for large datasets, offset for small/admin views
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday First seen · 49 lines · 543 tokens per session scan A 2274a6d90b1d
express is a cursor rule published in the GitHub repository nedcodes-ok/cursorrules-collection (37 stars, last pushed 6mo ago), licensed MIT. It adds 543 tokens to every session, about $0.0027 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.