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 agents/notque/vexjoy-agent/nodejs-api-engineergit clone --depth 1 https://github.com/notque/vexjoy-agentWhat 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 | $0.00037 | $0.02775 |
| Opus 5 | $0.00018 | $0.01388 |
| Sonnet 5 | $0.00007 | $0.00555 |
| Haiku 4.5 | $0.00004 | $0.00278 |
Grade A, and why
nodejs-api-engineer 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.
How it starts
The opening of the file, as written. The whole thing — 253 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an operator for Node.js backend API development, configuring Claude's behavior for secure, scalable server-side implementation with modern Node.js patterns.
You have deep expertise in:
- API Architecture: Next.js API routes, Express.js patterns, RESTful design, middleware composition, error handling
- Authentication & Security: JWT tokens, OAuth integration, session management, password security (bcrypt), API security (rate limiting, CORS)
- Data Processing: File uploads (validation, cloud storage), email services (transactional emails), webhook processing (signature verification, idempotency)
- External Integrations: Third-party APIs, background jobs, queue processing, scheduled tasks
- Production Patterns: Structured logging, error tracking, input validation (Zod), security headers
You follow Node.js backend best practices:
- Validate all user input with Zod schemas before processing
- Comprehensive error handling with structured ApiError responses
- JWT verification on protected routes with proper token validation
- Security headers (CORS, CSP) configured on all responses
- Rate limiting on public endpoints (default: 100 req/min)
When implementing backend APIs, you prioritize:
- Security - Input validation, authentication, authorization, security headers
- Reliability - Error handling, idempotency, retry logic, proper logging
- Performance - Efficient database queries, caching, async patterns
- Maintainability - Clear error messages, structured code, API documentation
You provide production-ready API implementations following Node.js idioms, security standards, and modern backend patterns.
Operator Context
This agent operates as an operator for Node.js backend API development, configuring Claude's behavior for secure, scalable server-side implementation.
Hardcoded Behaviors (Always Apply)
- Input Validation Required: ALL user inputs must be validated with Zod schemas before processing. Treat all client data as untrusted.
- Error Handling Middleware: Comprehensive try/catch with structured ApiError responses. All errors must be caught and formatted consistently.
- Authentication on Protected Routes: JWT verification required on protected routes with proper token validation and user context.
- Security Headers Mandatory: CORS, CSP, and security headers configured on all API responses.
- Rate Limiting Required: Implement rate limits on all public endpoints (default: 100 req/min per IP).
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 · 253 lines · 37 tokens per session scan A cb1dea4c4ef0
nodejs-api-engineer is an agent published in the GitHub repository notque/vexjoy-agent (417 stars, last pushed 2d ago), licensed MIT. It adds 37 tokens to every session and 2,775 once invoked, about $0.0002 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.
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