What is css-first AGENTS.md?

Repository instructions for css-first, a Bun monorepo containing several related packages. A monorepo keeps multiple packages in one repository; Bun is the tool used to install dependencies and run project commands.

Use them when working on the core library, command-line package, or Cloudflare Worker. They provide repository-wide and package-specific commands plus the project’s coding and naming conventions.

They explain the project structure and the commands needed to build, test, type-check, lint, deploy, and publish each package. This avoids running the wrong command or changing the wrong package.

How Luko248/css-first configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to Luko248/css-first. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/Luko248/css-first/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/Luko248/css-first

Made for: Codex, OpenCode.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/luko248/css-first/agents-md/github.svg)](https://agentmods.dev/instructions/luko248/css-first/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/luko248/css-first/agents-md"><img src="https://agentmods.dev/badge/instructions/luko248/css-first/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/luko248/css-first/agents-md"><img src="https://agentmods.dev/badge/instructions/luko248/css-first/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 611 This file is loaded in full into every session.

When invoked 611 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00611	$0.00611
Opus 5.5	$0.00244	$0.00244
Sonnet 5.5	$0.00122	$0.00122
Haiku 4.5	$0.00061	$0.00061

Measured 2mo ago against content hash 6552dd697c09, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

css-first 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 2mo 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.

AGENTS.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Repository Guidelines

Project Structure (Bun Monorepo)

mcp-css-first/
├── packages/
│   ├── core/           # @css-first/core - shared CSS services
│   │   └── src/        # MDN client, suggestions, features, types
│   ├── cli/            # @depthark/css-first - npm package (stdio/HTTP)
│   │   └── src/        # MCP server entrypoint
│   └── worker/         # @css-first/worker - Cloudflare Workers (SSE)
│       └── src/        # McpAgent class for remote MCP
├── wrangler.toml       # Cloudflare Workers deployment config
└── smithery.yaml       # Smithery registry config

Build, Test, and Development Commands

bun install               # Install all dependencies
bun run build             # Build all packages
bun run build:core        # Build @css-first/core only
bun run build:cli         # Build @depthark/css-first only
bun run typecheck         # Type check all packages
bun run lint              # Run ESLint
bun run deploy:worker     # Deploy to Cloudflare Workers
bun run publish:cli       # Publish CLI to npm

Package-specific commands (run from package directory)

packages/cli: bun run build - bundles with @vercel/ncc
packages/core: bun run build - compiles TypeScript
packages/worker: bun run dev - local Cloudflare development

Coding Style & Naming Conventions

TypeScript with strict mode enabled
Indentation is 2 spaces; prefer double quotes
Use camelCase for variables/functions, PascalCase for types/classes
Follow ESLint rules (unused args prefixed with _)

Package Dependencies

@css-first/core is internal (private: true), shared between cli and worker
@depthark/css-first is publishable to npm
@css-first/worker is private, deployed to Cloudflare only

Testing Guidelines

No automated test runner configured
Rely on bun run typecheck and manual CLI testing
Test worker locally with cd packages/worker && bun run dev

Commit & Pull Request Guidelines

Conventional Commits style: feat:, fix:, chore:, docs:, refactor:
Keep commits scoped to single changes
PRs should pass: build, lint, typecheck

Read the full file on GitHub · 61 lines

Changes

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.

2mo ago First seen · 61 lines · 611 tokens per session scan A 6552dd697c09

Subscribe to this mod's changes

css-first AGENTS.md is an instructions file published in the GitHub repository Luko248/css-first (5 stars, last pushed 9mo ago), licensed MIT. It adds 611 tokens to every session, about $0.0024 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 2026-08-31.

css-first AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
css-first AGENTS.mdLuko248/css-first	Instructions file	5	9mo ago	MIT	A	611	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

css-first: Instructions file for Codex