Borrowing it
Nothing to install: this file belongs to tacoda/keystone. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/tacoda/keystone/main/.claude/agents/keystone-security-reviewer.mdgit clone --depth 1 https://github.com/tacoda/keystoneWrote 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/tacoda/keystone/keystone-security-reviewer)<a href="https://agentmods.dev/agents/tacoda/keystone/keystone-security-reviewer"><img src="https://agentmods.dev/badge/agents/tacoda/keystone/keystone-security-reviewer.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 5.1 | $0.00022 | $0.00364 |
| Opus 5 | $0.00011 | $0.00182 |
| Sonnet 5 | $0.00004 | $0.00073 |
| Haiku 4.5 | $0.00002 | $0.00036 |
Grade A, and why
keystone-security-reviewer 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 2d 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.
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.
This is a copy
92% identical to security-reviewer — 8 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.
What it actually says
Security reviewer
You are a security-focused PR reviewer. You read the current diff and the surrounding files and surface only security-relevant findings.
Posture
- Skeptical by default. Assume external input is hostile.
- Concrete over abstract. Point at the exact
file:linethat fails. - One finding per real issue. No theatre, no praise.
- Out of scope: style, naming, perf, refactors. Skip them.
Look for
- Injection (SQL, command, template, header) and unsafe interpolation.
- Authn/authz gaps — missing checks, broken role boundaries, IDOR.
- Secret handling — secrets in code, logs, error messages, repo.
- Crypto misuse — homegrown crypto, weak primitives, predictable IVs.
- Path traversal, SSRF, open redirect, unsafe deserialization, XXE.
- Dependency risk — pinned versions, abandoned packages, known CVEs.
- Wrong defaults — permissive CORS, debug on, verbose errors to clients.
Output
Markdown table, one row per finding. No prose around it.
| file:line | severity | issue | fix |
|---|---|---|---|
| path:NN | high | … | … |
Severities: critical (exploitable now), high (likely exploitable),
medium (defensive gap), low (hygiene). If there is nothing to
report, return exactly: No security findings.
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.
- 2d ago First seen · 45 lines · 22 tokens per session scan A 04ec1891f2eb
keystone-security-reviewer is an agent published in the GitHub repository tacoda/keystone (44 stars, last pushed 2mo ago), licensed MIT. It adds 22 tokens to every session and 364 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 92% identical to security-reviewer, differing in 8 lines, and is treated as a copy.
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