Borrowing it
Nothing to install: this file belongs to saffron-health/libretto. 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/saffron-health/libretto/main/CLAUDE.mdgit clone --depth 1 https://github.com/saffron-health/librettoWrote 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/saffron-health/libretto/claude-md)<a href="https://agentmods.dev/instructions/saffron-health/libretto/claude-md"><img src="https://agentmods.dev/badge/instructions/saffron-health/libretto/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/saffron-health/libretto/claude-md"><img src="https://agentmods.dev/badge/instructions/saffron-health/libretto/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 | $0.00352 | $0.00352 |
| Opus 5 | $0.00176 | $0.00176 |
| Sonnet 5 | $0.00070 | $0.00070 |
| Haiku 4.5 | $0.00035 | $0.00035 |
Grade A, and why
libretto 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 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.
What it actually says
Libretto Monorepo
Releasing a New Version
Never manually edit packages/libretto/package.json version. Use the release script:
pnpm prepare-release [patch|minor|major]
This bumps the version, updates all SKILL.md files, syncs mirrors, validates parity, commits, pushes a release-v* branch, and opens a PR. The release CI workflow triggers automatically when the PR merges to main.
Publishing an Experimental Version
Temporarily set a pre-release version in packages/libretto/package.json and replace its workspace: and catalog: dependency ranges with published ranges. Then run:
pnpm publish:experimental
Approve npm's browser passkey prompt and verify the exact version installs in a clean project. Do not commit the temporary manifest edits.
Mirror System
Skill files and READMEs are mirrored across multiple locations. Do not hand-edit the mirrored copies. Edit source files only, then sync.
Source directories:
packages/libretto/skills/libretto/— interactive Libretto skill (source of truth)packages/libretto/skills/libretto-readonly/— read-only diagnosis skill (source of truth)
Mirror targets (generated — never edit directly):
.agents/skills/libretto/and.agents/skills/libretto-readonly/.claude/skills/libretto/and.claude/skills/libretto-readonly/
After any change to source skill files or READMEs:
pnpm sync:mirrors # sync all mirrored files
pnpm check:mirrors # validate everything is in sync
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 · 41 lines · 352 tokens per session scan A 77cbdad712ec
libretto CLAUDE.md is an instructions file published in the GitHub repository saffron-health/libretto (889 stars, last pushed 18d ago), licensed MIT. It adds 352 tokens to every session, about $0.0018 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 2026-08-30.
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