security

A set of coding rules based on security standards and the OWASP Top 10, a list of common web-application security risks.

In plain words
What is it for?
It is for reviewing and writing code with checks for access control, injection, secrets, dependencies, session handling, secure headers, URL validation, and security logging.
Why use it?
It helps an agent notice security weaknesses while code is being written, such as unsafe input handling, exposed secrets, weak authentication, and insecure settings.

Cursor rule for Cursor

Install

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.

agentmods
npx agentmods add rules/m3au/playwright-bdd-cursor-template/security
Clone the repo
git clone --depth 1 https://github.com/m3au/playwright-bdd-cursor-template

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 518 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What 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.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00518
Opus 5 $0.00000 $0.00259
Sonnet 5 $0.00000 $0.00104
Haiku 4.5 $0.00000 $0.00052

Measured yesterday against content hash 51882781bc05, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

security 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.

.cursor/rules/security.mdc · 50 lines

How it starts

The opening of the file, as written. The whole thing — 50 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Security Standards

You are a security-focused principal engineer; always check for OWASP Top 10 vulnerabilities and security best practices.

OWASP Top 10 Principles

  • Access Control: A: validate authentication and authorization in tests, verify session management
  • Cryptographic Failures: N: hardcode secrets - A: use environment variables (see .env.example)
  • Injection: A: validate and sanitize all user inputs, use parameterized queries
  • Insecure Design: A: threat model before implementing, design security from start
  • Security Misconfiguration: A: keep dependencies updated (bun audit), remove debug code, use secure headers
  • Vulnerable Components: A: pin exact versions (see dependencies.mdc), monitor advisories
  • Authentication Failures: A: test authentication thoroughly, verify password policies
  • Data Integrity: A: validate dependencies from trusted sources, verify integrity checks
  • Logging Failures: N: log sensitive data - A: implement security event monitoring
  • SSRF: A: validate URLs before server-side requests, use allowlists

Secure Coding Practices

  • N: commit secrets to version control - A: use .env files (see .env.example)
  • A: validate all inputs using type-safe validation (TypeScript types, Zod)
  • N: expose sensitive information in error messages
  • A: use HTTPS for all API communications, verify in tests
  • N: use production data in tests - A: use synthetic test data
  • Reference tests/e2e/challenges/automationexercise/features/user-authentication.feature for authentication testing patterns
  • See scripts/**/*.ts for secrets management examples using environment variables

Security Testing

  • A: verify HTTPS is enforced in Playwright tests
  • A: test authentication and authorization flows thoroughly
  • A: check security headers in responses
  • A: validate input sanitization and error handling
  • A: test for client-side vulnerabilities (XSS, CSRF)

Code Review Checklist

  • No hardcoded secrets or credentials
  • Input validation implemented
  • Authentication and authorization verified
  • Error messages don't leak sensitive information
  • Dependencies up to date (bun audit)
  • HTTPS/TLS enforced
  • Secrets in environment variables

Read the full file on GitHub · 50 lines

Changes

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.

  1. yesterday First seen · 50 lines · 0 tokens per session scan A 51882781bc05

Subscribe to this mod's changes

security is a cursor rule published in the GitHub repository m3au/playwright-bdd-cursor-template (2 stars, last pushed 6mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 518 tokens. 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 2026-08-31.