Borrowing it
Nothing to install: this file belongs to understudylabs/understudy-agent-tools. 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/understudylabs/understudy-agent-tools/main/CLAUDE.mdgit clone --depth 1 https://github.com/understudylabs/understudy-agent-toolsWrote 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/understudylabs/understudy-agent-tools/claude-md)<a href="https://agentmods.dev/instructions/understudylabs/understudy-agent-tools/claude-md"><img src="https://agentmods.dev/badge/instructions/understudylabs/understudy-agent-tools/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/understudylabs/understudy-agent-tools/claude-md"><img src="https://agentmods.dev/badge/instructions/understudylabs/understudy-agent-tools/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 | $0.00478 | $0.00478 |
| Opus 5.5 | $0.00191 | $0.00191 |
| Sonnet 5.5 | $0.00096 | $0.00096 |
| Haiku 4.5 | $0.00048 | $0.00048 |
Grade A, and why
understudy-agent-tools 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 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.
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
CLAUDE.md
Guidance for Claude Code (and any coding agent) working in this repository.
The operating guide for agents is AGENTS.md. Read it first.
It covers the two ways an agent is used here and what to do in each.
Prime directive (the 10-second version)
There are two kinds of visitor to this repo. Figure out which one you have before doing anything else:
- A user who wants to use Understudy — improve an LLM app, cut cost, run a
local model, pick a route. Install the plugin first (the
install-pluginskill), then run theonboardskill. The plugin's skills are what let you explain what Understudy is, why it matters, and actually solve their problem. Don't try to wing it from the source tree. - A contributor working on this repo — follow the boundary, architecture,
and extraction rules in
AGENTS.md.
When in doubt, assume the first. Most people here want help with their LLM workload, not to edit the library.
How to behave
Adopt the engagement doctrine in
docs/engagement-and-pacing.md: plan up front,
say how long things take before you start them, background long-running work
and stay interactive while it runs, and meet the user where they are using their
~/.understudy/profile.json. The
understudy skill is the orchestrator for the
whole improvement loop.
Run on Fable, parallelize like the model card
For your own reasoning and orchestration, prefer Claude Fable 5 when the
harness offers a choice, and follow
docs/agent-model-and-parallelism.md:
fan out independent work to non-blocking subagents, reserve parallelism for
the hard slow tail, keep workers long-lived instead of respawning, and verify
subagent claims before reporting them.
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 · 43 lines · 478 tokens per session scan A 08f150c87b46
understudy-agent-tools CLAUDE.md is an instructions file published in the GitHub repository understudylabs/understudy-agent-tools (18 stars, last pushed yesterday), licensed MIT. It adds 478 tokens to every session, about $0.0019 per session on Opus 5.5. 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.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
vscode model-prompts.instructions.md
Model-specific prompt authoring and registry guidelines.