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 skills/marcecandil/agent-context-kit/securitynpx skills add MarceCandil/agent-context-kit --skill securitygit clone --depth 1 https://github.com/MarceCandil/agent-context-kitWhat 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 | $0.00020 | $0.00275 |
| Opus 5 | $0.00010 | $0.00138 |
| Sonnet 5 | $0.00004 | $0.00055 |
| Haiku 4.5 | $0.00002 | $0.00028 |
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.
What it actually says
Skill: Security
Secrets & credentials
- Never commit secrets (API keys, tokens, passwords) to the repo.
- Use environment variables; document required vars in
.cursor/rules/00-agents.mdcor.env.example. - If a secret is accidentally committed, rotate it immediately and scrub from history.
Input validation
- Validate and sanitize all user input on the server side.
- Use allowlists over denylists where possible.
- Escape output to prevent XSS (HTML, URL, SQL contexts).
Authentication & authorization
- Verify auth on every protected endpoint; don't rely on client-side checks alone.
- Use established libraries (e.g., bcrypt for hashing, JWT with short expiry).
- Implement proper session management (secure cookies, CSRF protection).
API security
- Use HTTPS for all external calls.
- Validate Content-Type and reject unexpected payloads.
- Rate-limit sensitive endpoints (login, password reset).
Logging & observability
- Never log sensitive data (passwords, tokens, PII).
- Configure redaction for common sensitive fields.
- Log auth failures and suspicious activity for audit.
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 · 35 lines · 20 tokens per session scan A a5cf189a83e7
security is a skill published in the GitHub repository MarceCandil/agent-context-kit (2 stars, last pushed 6mo ago), licensed MIT. It adds 20 tokens to every session and 275 once invoked, about $0.0001 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 2026-08-31.
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