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.
git clone --depth 1 https://github.com/matank001/cursor-security-rulesWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/rules/matank001/cursor-security-rules/secure-dev-python)<a href="https://agentmods.dev/rules/matank001/cursor-security-rules/secure-dev-python"><img src="https://agentmods.dev/badge/rules/matank001/cursor-security-rules/secure-dev-python/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/rules/matank001/cursor-security-rules/secure-dev-python"><img src="https://agentmods.dev/badge/rules/matank001/cursor-security-rules/secure-dev-python.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00000 | $0.00565 |
| Opus 5.5 | $0.00000 | $0.00226 |
| Sonnet 5.5 | $0.00000 | $0.00113 |
| Haiku 4.5 | $0.00000 | $0.00056 |
Grade A, and why
secure-dev-python scanned grade A with 1 finding 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 1mo ago.
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.
Runs shell commandslowCapability
Expected in a hook, worth knowing in a rule or an instructions file.
- **Rule:** Avoid using `os.system`, `subprocess.run`, or similar functions. Use parameterized APIs or sandboxed environments if needed. How it starts
The opening of the file, as written. The whole thing — 47 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Secure Python Development
These rules apply to all Python code in the repository and aim to prevent common security risks through disciplined use of input validation, output encoding, and safe APIs.
All violations must include a clear explanation of which rule was triggered and why, to help developers understand and fix the issue effectively.
if code is in violation add a comment explaining why. don't generate code that violates these rules.
1. Do Not Use User Input in File Paths
- Rule: Never use
input(),request.args,request.form,sys.argv, or similar sources directly in file paths or file operations.
2. Always Sanitize and Validate External Input
- Rule: All external input must be sanitized and validated before being used in logic, database queries, file access, or rendering.
3. Avoid eval, exec, and compile on Dynamic Input
- Rule: Do not use
eval(),exec(), orcompile()on any user-controllable input.
4. Use Constant-Time Comparison for Secrets
- Rule: Use
hmac.compare_digest()for comparing secrets like tokens, passwords, or signatures to prevent timing attacks.
5. Do Not Log Sensitive Data
- Rule: Logs must not contain passwords, tokens, API keys, private keys, or personally identifiable information (PII).
6. Avoid Subprocess Calls with User Input
- Rule: Avoid using
os.system,subprocess.run, or similar functions. Use parameterized APIs or sandboxed environments if needed.
7. Escape Output in Web Contexts
- Rule: When rendering user-generated content into HTML, JSON, or command-line output, always apply appropriate escaping.
8. Avoid Hardcoded Secrets
- Rule: Do not hardcode passwords, tokens, or secret keys in source code. Use environment variables or a secure configuration service.
9. Restrict Dynamic Imports
- Rule: Avoid
__import__()orimportlibwith dynamic or user-controlled values.
10. Avoid Loose Type Comparisons in Security Logic
- Rule: Use strict type checks and avoid logic that relies on implicit truthiness (e.g.,
if token == 0:) when handling authentication or access control.
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.
- 1mo ago First seen · 47 lines · 565 tokens per session scan A c4cc160b53c1
secure-dev-python is a cursor rule published in the GitHub repository matank001/cursor-security-rules (381 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 565 tokens. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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