Borrowing it
Nothing to install: this file belongs to therealarthur/myrlin-workbook. 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/therealarthur/myrlin-workbook/main/CLAUDE.mdgit clone --depth 1 https://github.com/therealarthur/myrlin-workbookWrote 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/instructions/therealarthur/myrlin-workbook/claude-md)<a href="https://agentmods.dev/instructions/therealarthur/myrlin-workbook/claude-md"><img src="https://agentmods.dev/badge/instructions/therealarthur/myrlin-workbook/claude-md/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/instructions/therealarthur/myrlin-workbook/claude-md"><img src="https://agentmods.dev/badge/instructions/therealarthur/myrlin-workbook/claude-md.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 | $0.01757 | $0.01757 |
| Opus 5 | $0.00879 | $0.00879 |
| Sonnet 5 | $0.00351 | $0.00351 |
| Haiku 4.5 | $0.00176 | $0.00176 |
Grade B, and why
myrlin-workbook CLAUDE.md 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 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.
Reads agent configuration directoriesmediumAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
- Do NOT edit `~/.claude/settings.json` or any global config The source is not reproduced here
Licensed AGPL-3.0
The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.
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 · 151 lines · 1,757 tokens per session scan B 049ce55d2d37
myrlin-workbook CLAUDE.md is an instructions file published in the GitHub repository therealarthur/myrlin-workbook (381 stars, last pushed 7d ago), licensed AGPL-3.0. It adds 1,757 tokens to every session, about $0.0088 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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