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/AGENTS.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/agents-md)<a href="https://agentmods.dev/instructions/understudylabs/understudy-agent-tools/agents-md"><img src="https://agentmods.dev/badge/instructions/understudylabs/understudy-agent-tools/agents-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/agents-md"><img src="https://agentmods.dev/badge/instructions/understudylabs/understudy-agent-tools/agents-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 | $0.01944 | $0.01944 |
| Opus 5.5 | $0.00778 | $0.00778 |
| Sonnet 5.5 | $0.00389 | $0.00389 |
| Haiku 4.5 | $0.00194 | $0.00194 |
Grade A, and why
understudy-agent-tools 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 8d 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 — 204 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
This file tells a coding agent how to operate in this repo. There are two audiences — serve the right one.
Are you helping a user, or editing the library?
- Helping a user get value from Understudy (improve an LLM app, cut cost/latency, run a local model, pick a route) → start with Install the agent adapter below, then run onboarding. This is the common case.
- Contributing to this repo (changing skills, CLI, docs) → skip to Working on this repo.
When unsure, assume the user wants help with their workload, not to edit the library.
Install the agent adapter (do this first for users)
Understudy is delivered through the coding agent's local skill/plugin surface (or, for cloud-based agents like Devin, through the globally installed CLI and repository rule injection). Install that adapter — do not try to operate from the raw source tree. The adapter loads the skills, and the skills are the product: they are what let you explain what Understudy is, why it matters, and walk the user from a captured trace to a measured, shipped improvement. Without them you are guessing; with them you have the playbooks, the execution contracts, and the adaptive optimization loop.
Recommend installation to the user in plain terms, e.g.: "Understudy works best
inside your coding agent — installation is local and reversible, and its hosted
workflows stay bound to the route and budget you choose. Want me to install it?"
Then use the install-agent-adapter
skill. Claude Code remains the preferred default when multiple agents are
available:
claude plugin marketplace add "$(git rev-parse --show-toplevel)"
claude plugin install understudy@understudy-skills
The user then types /reload-plugins once — no restart needed. You cannot
run that step yourself; surface it and wait.
It is reversible — say so
Installing is low-risk and fully reversible. Tell the user the uninstall path up front so saying yes feels safe:
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.
- 8d ago Changed · +1 lines · +20 tokens per session c56183471815
- 1mo ago Changed · +9 lines · +145 tokens per session f621d94b1983
- 1mo ago First seen · 194 lines · 1,779 tokens per session scan A e86fc1bc7a4d
understudy-agent-tools is an instructions file published in the GitHub repository understudylabs/understudy-agent-tools (18 stars, last pushed yesterday), licensed MIT. It adds 1,944 tokens to every session, about $0.0078 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.