Borrowing it
Nothing to install: this file belongs to axiomantic/spellbook. 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/axiomantic/spellbook/main/.claude/skills/spellbook-auditing/SKILL.mdgit clone --depth 1 https://github.com/axiomantic/spellbookWrote 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/axiomantic/spellbook/spellbook-auditing)<a href="https://agentmods.dev/skills/axiomantic/spellbook/spellbook-auditing"><img src="https://agentmods.dev/badge/skills/axiomantic/spellbook/spellbook-auditing/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/axiomantic/spellbook/spellbook-auditing"><img src="https://agentmods.dev/badge/skills/axiomantic/spellbook/spellbook-auditing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00042 | $0.04102 |
| Opus 5 | $0.00021 | $0.02051 |
| Sonnet 5 | $0.00008 | $0.00820 |
| Haiku 4.5 | $0.00004 | $0.00410 |
Grade A, and why
spellbook-auditing 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 9d 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.
How it starts
The opening of the file, as written. The whole thing — 567 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Audit Spellbook
You are auditing the spellbook project itself. This skill orchestrates parallel subagents to comprehensively analyze skills, commands, docs, and prompts for optimization opportunities.
Invariant Principles
- Parallelism maximizes audit coverage - All audit agents launch simultaneously; sequential execution wastes context
- Token efficiency compounds - Small savings multiply across always-loaded descriptions, skill bodies, and runtime
- CSO prevents workflow leak - Descriptions trigger only; workflow in description = Claude follows description not skill
- Evidence over claims - Every finding requires file/line/example proof; no unsubstantiated optimization recommendations
- Actionable over diagnostic - Report must produce implementable items with clear priority
Trigger Conditions
Use this skill when:
- User asks to "audit spellbook", "optimize skills", "review spellbook"
- Before major releases to ensure quality
- When concerned about token usage or instruction bloat
- Periodically for maintenance
Execution Flow
Phase 1: Launch Parallel Audit Subagents
Launch ALL of these subagents in a SINGLE message (parallel execution):
1. Factcheck Agent
Audit all documentation in spellbook for factual accuracy.
Files to check:
- README.md
- docs/**/*.md
- CHANGELOG.md
- Any claims in skill/command descriptions
For each claim found:
1. Identify the assertion
2. Verify against: code, external sources, logical consistency
3. Flag unverifiable or incorrect claims
Output: JSON array of {file, line, claim, status: "verified"|"unverified"|"incorrect", evidence}
2. Instruction Engineering Compliance Agent
Audit all instruction files against instruction-engineering principles.
Files: skills/*/SKILL.md, commands/*.md, rules/*.md
Check for:
- Clear role definition
- Explicit trigger conditions
- Structured output formats
- Edge case handling
- Appropriate use of examples (not excessive)
- Action-oriented language
- Avoidance of ambiguity
Output: JSON array of {file, issues: [{principle, violation, suggestion}], score: 0-100}
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.
- 9d ago First seen · 567 lines · 42 tokens per session scan A bb5c21feabf7
spellbook-auditing is a skill published in the GitHub repository axiomantic/spellbook (10 stars, last pushed yesterday), licensed MIT. It adds 42 tokens to every session and 4,102 once invoked, about $0.0002 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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