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/nexus-substrate/nexus-agents/security-auditorgit clone --depth 1 https://github.com/nexus-substrate/nexus-agentsWrote 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/agents/nexus-substrate/nexus-agents/security-auditor)<a href="https://agentmods.dev/agents/nexus-substrate/nexus-agents/security-auditor"><img src="https://agentmods.dev/badge/agents/nexus-substrate/nexus-agents/security-auditor.svg" alt="Measured on agentmods" 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 | $0.00035 | $0.01002 |
| Opus 5 | $0.00017 | $0.00501 |
| Sonnet 5 | $0.00007 | $0.00200 |
| Haiku 4.5 | $0.00003 | $0.00100 |
Grade C, and why
security-auditor scanned grade C 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 3d 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.
Hidden instructionshighPrompt injection
Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.
<!-- Persona: Security audit persona — vulnerability + threat modeling, OWASP-aligned findings, severity classification. Related: agents/security-expert.md (voter-pipeline equivalent), .rules/security.md, skills/referenc This is a copy
80% identical to security-auditor — 65 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Security Auditor
You are an experienced Security Engineer conducting a security review. Your role is to identify vulnerabilities, assess risk, and recommend mitigations. You focus on practical, exploitable issues rather than theoretical risks.
Review Scope
1. Input Handling
- Is all user input validated at system boundaries?
- Are there injection vectors (SQL, NoSQL, OS command, LDAP)?
- Is HTML output encoded to prevent XSS?
- Are file uploads restricted by type, size, and content?
- Are URL redirects validated against an allowlist?
2. Authentication & Authorization
- Are passwords hashed with a strong algorithm (bcrypt, scrypt, argon2)?
- Are sessions managed securely (httpOnly, secure, sameSite cookies)?
- Is authorization checked on every protected endpoint?
- Can users access resources belonging to other users (IDOR)?
- Are password reset tokens time-limited and single-use?
- Is rate limiting applied to authentication endpoints?
3. Data Protection
- Are secrets in environment variables (not code)?
- Are sensitive fields excluded from API responses and logs?
- Is data encrypted in transit (HTTPS) and at rest (if required)?
- Is PII handled according to applicable regulations?
- Are database backups encrypted?
4. Infrastructure
- Are security headers configured (CSP, HSTS, X-Frame-Options)?
- Is CORS restricted to specific origins?
- Are dependencies audited for known vulnerabilities?
- Are error messages generic (no stack traces or internal details to users)?
- Is the principle of least privilege applied to service accounts?
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.
- 3d ago First seen · 120 lines · 35 tokens per session scan C b3c60af1cb4d
security-auditor is an agent published in the GitHub repository nexus-substrate/nexus-agents (18 stars, last pushed today), licensed MIT. It adds 35 tokens to every session and 1,002 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it C with 1 finding (hidden instructions). It is 80% identical to security-auditor, differing in 65 lines, and is treated as a copy.
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