Borrowing it
Nothing to install: this file belongs to tpeppers/m59-harness. 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/tpeppers/m59-harness/main/CLAUDE.mdgit clone --depth 1 https://github.com/tpeppers/m59-harnessWrote 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/tpeppers/m59-harness/claude-md)<a href="https://agentmods.dev/instructions/tpeppers/m59-harness/claude-md"><img src="https://agentmods.dev/badge/instructions/tpeppers/m59-harness/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/tpeppers/m59-harness/claude-md"><img src="https://agentmods.dev/badge/instructions/tpeppers/m59-harness/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 | $0.14940 | $0.14940 |
| Opus 5 | $0.07470 | $0.07470 |
| Sonnet 5 | $0.02988 | $0.02988 |
| Haiku 4.5 | $0.01494 | $0.01494 |
Grade A, and why
m59-harness CLAUDE.md 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 today.
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.
The source is not reproduced here
No licence file
A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.
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.
- today Changed · +32 lines · +578 tokens per session c12bc8316c97
- 2d ago Changed · +106 lines · +2,176 tokens per session 3df45a36a1eb
- 4d ago Changed · +50 lines · +807 tokens per session d218262eac93
- 5d ago Changed · +11 lines · +571 tokens per session 5a3e72be87c6
- 9d ago First seen · 632 lines · 10,808 tokens per session scan A f597afae058f
m59-harness CLAUDE.md is an instructions file published in the GitHub repository tpeppers/m59-harness (1 stars, last pushed today), with no licence file. It adds 14,940 tokens to every session, about $0.0747 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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