ax CLAUDE.md

A development guide for applications built with Bun, a JavaScript and TypeScript runtime. It specifies Bun-based choices for servers, databases, APIs, frontend code, dependencies, and tests instead of equivalent Node.js tools.

In plain words
What is it for?
Building and serving APIs, using SQLite, Redis, or Postgres, handling WebSockets, installing packages, loading environment settings, and writing or running tests with Bun.
Why use it?
It keeps the codebase consistent and avoids mixing incompatible tools or project conventions.

Instructions file

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/yusukebe/ax/claude-md
Clone the repo
git clone --depth 1 https://github.com/yusukebe/ax
Per session 722 This file is loaded in full into every session.
When invoked 722 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin 88% copy Near-identical to another mod 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.

ModelPer sessionOnce invoked
Fable 5 $0.00722 $0.00722
Opus 5 $0.00361 $0.00361
Sonnet 5 $0.00144 $0.00144
Haiku 4.5 $0.00072 $0.00072

Measured 2d ago against content hash 978f9f20cffb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ax 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 2d 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.

Origin

This is a copy

88% identical to claude-peers-mcp CLAUDE.md — 36 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

CLAUDE.md · 106 lines

How it starts

The opening of the file, as written. The whole thing — 106 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Default to using Bun instead of Node.js.

  • Use bun <file> instead of node <file> or ts-node <file>
  • Use bun test instead of jest or vitest
  • Use bun build <file.html|file.ts|file.css> instead of webpack or esbuild
  • Use bun install instead of npm install or yarn install or pnpm install
  • Use bun run <script> instead of npm run <script> or yarn run <script> or pnpm run <script>
  • Use bunx <package> <command> instead of npx <package> <command>
  • Bun automatically loads .env, so don't use dotenv.

APIs

  • Bun.serve() supports WebSockets, HTTPS, and routes. Don't use express.
  • bun:sqlite for SQLite. Don't use better-sqlite3.
  • Bun.redis for Redis. Don't use ioredis.
  • Bun.sql for Postgres. Don't use pg or postgres.js.
  • WebSocket is built-in. Don't use ws.
  • Prefer Bun.file over node:fs's readFile/writeFile
  • Bun.$ls instead of execa.

Testing

Use bun test to run tests.

import { test, expect } from "bun:test";

test("hello world", () => {
  expect(1).toBe(1);
});

Frontend

Use HTML imports with Bun.serve(). Don't use vite. HTML imports fully support React, CSS, Tailwind.

Server:

import index from "./index.html"

Bun.serve({
  routes: {
    "/": index,
    "/api/users/:id": {
      GET: (req) => {
        return new Response(JSON.stringify({ id: req.params.id }));
      },
    },
  },
  // optional websocket support
  websocket: {
    open: (ws) => {
      ws.send("Hello, world!");
    },
    message: (ws, message) => {
      ws.send(message);
    },
    close: (ws) => {
      // handle close
    }
  },
  development: {
    hmr: true,
    console: true,
  }
})

HTML files can import .tsx, .jsx or .js files directly and Bun's bundler will transpile & bundle automatically. <link> tags can point to stylesheets and Bun's CSS bundler will bundle.

<html>
  <body>
    <h1>Hello, world!</h1>
    <script type="module" src="./frontend.tsx"></script>
  </body>
</html>

Read the full file on GitHub · 106 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.

  1. 2d ago First seen · 106 lines · 722 tokens per session scan A 978f9f20cffb

Subscribe to this mod's changes

ax CLAUDE.md is an instructions file published in the GitHub repository yusukebe/ax (700 stars, last pushed 28d ago), licensed MIT. It adds 722 tokens to every session, about $0.0036 per session on Opus 5. A static security scan graded it A with 0 findings. It is 88% identical to claude-peers-mcp CLAUDE.md, differing in 36 lines, and is treated as a copy.

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