Borrowing it
Nothing to install: this file belongs to youdotcom-oss/agent-skills. 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/youdotcom-oss/agent-skills/main/AGENTS.mdgit clone --depth 1 https://github.com/youdotcom-oss/agent-skillsWrote 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/youdotcom-oss/agent-skills/agents-md)<a href="https://agentmods.dev/instructions/youdotcom-oss/agent-skills/agents-md"><img src="https://agentmods.dev/badge/instructions/youdotcom-oss/agent-skills/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/youdotcom-oss/agent-skills/agents-md"><img src="https://agentmods.dev/badge/instructions/youdotcom-oss/agent-skills/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 | $0.01085 | $0.01085 |
| Opus 5.5 | $0.00434 | $0.00434 |
| Sonnet 5.5 | $0.00217 | $0.00217 |
| Haiku 4.5 | $0.00109 | $0.00109 |
Grade A, and why
agent-skills AGENTS.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.
How it starts
The opening of the file, as written. The whole thing — 69 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Instructions
This repo packages You.com skills and plugin manifests for multiple coding-agent surfaces. Keep changes small, verified, and tied to the requested surface.
Tooling discovery
- Prefer Bun for TypeScript, scripts, orchestration, and running checks. Use Bun to trigger Python and TypeScript tooling unless an existing script says otherwise.
- Bun MCP docs: https://bun.com/docs/mcp
- Before choosing commands, scan
package.json,biome.json, and relevantpackages/*/package.jsonscripts. Do not guess command names. - Root checks currently flow through Bun:
bun test,bun run check,bun run check:types,bun run check:ts,bun run check:package. - Package checks often differ. Use the package script in
packages/<name>/package.jsonfor package-scoped work.
Minimal-implementation directive
Before writing code, resolve the task at the FIRST step that holds:
- Does this capability need to exist for the stated task? If it is speculative, do not build it. Say so in one sentence and stop.
- Does something already in THIS codebase do it? Reuse it. Read before you write; re-implementing a helper that lives three files over is the most common waste.
- Does the standard library or the runtime/platform already do it? (
<input type="date">, a DB unique constraint, a CSS rule.) Use it. - Does an already-installed dependency do it? Use it. Do not add a new dependency for something a few lines cover.
- Can it be one clear expression? Write the one expression.
- Otherwise: the smallest code that fully handles the task.
NON-NEGOTIABLE FLOOR: none of the steps above may remove any of these, and "minimal" is never a reason to drop them:
- input validation at trust boundaries (anything crossing a process, network, file, or user edge),
- error handling that prevents data loss or silent corruption,
- authn/authz and other security checks,
- accessibility for anything a human interacts with.
If a step would require cutting one of these, that step does not apply.
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 Changed · +1 lines · +74 tokens per session 074aed8b11be
- 1mo ago Changed · -2 lines · -81 tokens per session 244d4fc5c7b2
- 1mo ago First seen · 70 lines · 1,092 tokens per session scan A 3d67329f50ab
agent-skills AGENTS.md is an instructions file published in the GitHub repository youdotcom-oss/agent-skills (94 stars, last pushed today), licensed MIT. It adds 1,085 tokens to every session, about $0.0043 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).
deno copilot-instructions.md
Copilot instructions for denoland/deno, covering deno development guide for github copilot, network access, high level overview, key directories and key files to understand first.