Borrowing it
Nothing to install: this file belongs to youdotcom-oss/dx-toolkit. 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/dx-toolkit/main/AGENTS.mdgit clone --depth 1 https://github.com/youdotcom-oss/dx-toolkitWrote 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/dx-toolkit/agents-md)<a href="https://agentmods.dev/instructions/youdotcom-oss/dx-toolkit/agents-md"><img src="https://agentmods.dev/badge/instructions/youdotcom-oss/dx-toolkit/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/dx-toolkit/agents-md"><img src="https://agentmods.dev/badge/instructions/youdotcom-oss/dx-toolkit/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 | $0.01314 | $0.01314 |
| Opus 5.5 | $0.00526 | $0.00526 |
| Sonnet 5.5 | $0.00263 | $0.00263 |
| Haiku 4.5 | $0.00131 | $0.00131 |
Grade A, and why
dx-toolkit 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 — 203 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You.com DX Toolkit
Bun workspace for You.com developer packages and integrations.
Prefer the root README.md for user-facing setup. This file is for maintainers and coding agents working inside the repo.
Behavioral Guidelines
Think Before Coding
State assumptions. Surface tradeoffs. If multiple interpretations exist, present them instead of picking silently. If the repo already answers the question, use the codebase as the source of truth.
Simplicity First
Make the smallest change that solves the request. Do not add abstractions, fallbacks, or cleanup outside the task unless the change requires them.
Surgical Changes
Touch only the files the task needs. Match existing style. Remove imports or variables you orphan, but leave unrelated code alone.
Goal-Driven Execution
Turn work into verifiable outcomes. For behavior-changing feature or fix work,
use the tdd skill and work in red-green-refactor slices. For docs-only or
instruction-only edits, targeted doc validation is enough.
Validate Before Handoff
Run the narrowest checks that prove the change. If you skip executable tests,
say why. Before trusting repo docs, verify the current state with rg, find,
git log, or the relevant workflow/package files.
Repo Shape
Core Paths
| Path | Purpose |
|---|---|
.agents/skills/ |
Canonical skill directory for this repo |
packages/ |
Publishable packages |
.github/workflows/ |
CI, review, publish, and security workflows |
scripts/ |
Repo utilities and validation scripts |
docs/ |
Supporting docs such as performance notes |
Current Packages
packages/clipackages/mcppackages/ai-sdk-pluginpackages/langchain
Skill Surface
Prefer .agents/skills/ as the canonical agent workflow surface. Current
shared skills:
grill-mefor stress-testing plans or designsoptimize-agents-mdfor tightening repo instructionsreview-guidelinesfor code review conventionstddfor behavior-changing feature and fix worktypescript-lspfor type-aware TypeScript symbol exploration
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 · 203 lines · 1,314 tokens per session scan A a93e6426c400
dx-toolkit AGENTS.md is an instructions file published in the GitHub repository youdotcom-oss/dx-toolkit (25 stars, last pushed 1mo ago), licensed MIT. It adds 1,314 tokens to every session, about $0.0053 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.