Borrowing it
Nothing to install: this file belongs to aarora79/claude-code-usage-analyzer. 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/aarora79/claude-code-usage-analyzer/main/.claude/skills/security-check/SKILL.mdgit clone --depth 1 https://github.com/aarora79/claude-code-usage-analyzerWrote 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/skills/aarora79/claude-code-usage-analyzer/security-check)<a href="https://agentmods.dev/skills/aarora79/claude-code-usage-analyzer/security-check"><img src="https://agentmods.dev/badge/skills/aarora79/claude-code-usage-analyzer/security-check/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/skills/aarora79/claude-code-usage-analyzer/security-check"><img src="https://agentmods.dev/badge/skills/aarora79/claude-code-usage-analyzer/security-check.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 | $0.00096 | $0.01544 |
| Opus 5.5 | $0.00038 | $0.00618 |
| Sonnet 5.5 | $0.00019 | $0.00309 |
| Haiku 4.5 | $0.00010 | $0.00154 |
Grade B, and why
security-check scanned grade B 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.
Harvests environment variablesmediumData exfiltration
Enumerating or grepping the environment for keys collects credentials unrelated to what the mod says it does.
- **Secret / PII leakage (R3, #7):** reports, logs, and committed example data record counts/costs/model ids, never file paths that reveal project names, credentials, or prompt content. `--debug` logging must not dump se Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
How it starts
The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Security Check Skill (Cipher)
Run a focused security review over the repository's pending changes, adopting the Cipher security-engineer persona, and fix any security problems found before code is committed.
This skill is the security gate referenced by CLAUDE.md. It MUST be run:
- Before any commit on any branch.
- Before opening or updating a PR.
- Whenever a new enhancement, feature, or refactor is added — both before writing security-sensitive code (to know the rules) and after implementing it (to catch regressions).
Reference material (read first)
Two bundled files define the review:
- personas/security-engineer.md — the Cipher persona: scope, evaluation areas, review questions, and the output format.
- personas/security-patterns.md — the catalog of security anti-patterns and the Review Checklist. This is the substantive source of truth for what counts as a defect.
Read security-patterns.md before reviewing. For every changed file, walk its Review Checklist and flag any pattern the diff reintroduces. Treat a matched anti-pattern as a blocker until it is justified or fixed.
What this repository is
This is a command-line usage-and-cost analysis tool for Claude Code. It shells out to the ccusage CLI (via npx) to gather usage data, downloads a pricing table from LiteLLM over HTTPS, computes statistics, and writes JSON/Markdown/Quarto reports plus charts. There is no web server, no authentication surface, and no database.
So the dominant security surface here is narrow but real: spawning a subprocess (npx ccusage), fetching a remote URL, parsing untrusted JSON from both, and writing reports that could leak data. The classic web-auth patterns (broken access control, CSRF, token boundaries) do not apply unless a change adds an HTTP surface; the day-to-day risk lives in subprocess safety, SSRF/URL handling, untrusted-input parsing, and log/report hygiene.
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 · 90 lines · 96 tokens per session scan B f107b2e4feb1
security-check is a skill published in the GitHub repository aarora79/claude-code-usage-analyzer (6 stars, last pushed 2mo ago), licensed MIT. It adds 96 tokens to every session and 1,544 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it B with 1 finding (harvests environment variables). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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