Agent Prompt: CLAUDE.md creation

Agent Prompt: CLAUDE.md creation is an agent for Claude Code from openonion/connectonion. It costs 23 tokens per session (381 once invoked), scanned C, original, Apache-2.0.

A system prompt for examining a codebase and creating or improving a CLAUDE.md file, project instructions that help future Claude Code sessions work in the repository. It focuses on useful commands, high-level architecture, and relevant existing project rules.

In plain words
What is it for?
Use it to document how to build, test, lint, and understand a codebase for future Claude Code work.
Why use it?
It gathers repository-specific guidance in one place without filling the file with generic advice or details that are easy to discover. It also accounts for existing README, Cursor, and Copilot instructions.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: mentions CLAUDE.md; mentions Claude Code; mentions Cursor.

Good fit Use it to document how to build, test, lint, and understand a codebase for future Claude Code work.

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Install with agentmods
npx agentmods add agents/openonion/connectonion/agent-prompt-claudemd-creation
About the project

ConnectOnion is an open-source, template-first toolkit for building, debugging, deploying, and operating AI agents. Developers use its command-line tools and Python runtime to create agents, add tools, connect services, deploy them, and make them callable by other agents, while the catalogue entries are related agents, skills, and instructions.

openonion/connectonion · 1,480 stars · on GitHub · docs.connectonion.com

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.

Clone the repo
git clone --depth 1 https://github.com/openonion/connectonion

Made for: Claude Code.

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.

agentmods badge for Agent Prompt: CLAUDE.md creation

README.md
[![agentmods](https://agentmods.dev/badge/agents/openonion/connectonion/agent-prompt-claudemd-creation/github.svg)](https://agentmods.dev/agents/openonion/connectonion/agent-prompt-claudemd-creation)
Your own site
<a href="https://agentmods.dev/agents/openonion/connectonion/agent-prompt-claudemd-creation"><img src="https://agentmods.dev/badge/agents/openonion/connectonion/agent-prompt-claudemd-creation/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.

agentmods 80×15 button for Agent Prompt: CLAUDE.md creation

Your own site · 80×15
<a href="https://agentmods.dev/agents/openonion/connectonion/agent-prompt-claudemd-creation"><img src="https://agentmods.dev/badge/agents/openonion/connectonion/agent-prompt-claudemd-creation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 23 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 381 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00023 $0.00381
Opus 5 $0.00012 $0.00191
Sonnet 5 $0.00005 $0.00076
Haiku 4.5 $0.00002 $0.00038

Measured 10d ago against content hash 96ad3f2b5f1c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade C, and why

Agent Prompt: CLAUDE.md creation scanned grade C with 1 finding 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 10d 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.

Hidden instructionshighPrompt injection

Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.

<!-- name: 'Agent Prompt: CLAUDE.md creation' description: System prompt for analyzing codebases and creating CLAUDE.md documentation files ccVersion: 2.0.14 -->
connectonion/useful_prompts/cc_prompt/prompts/agents/agent-prompt-claudemd-creation.md · 27 lines

What it actually says

Please analyze this codebase and create a CLAUDE.md file, which will be given to future instances of Claude Code to operate in this repository.

What to add:

  1. Commands that will be commonly used, such as how to build, lint, and run tests. Include the necessary commands to develop in this codebase, such as how to run a single test.
  2. High-level code architecture and structure so that future instances can be productive more quickly. Focus on the "big picture" architecture that requires reading multiple files to understand.

Usage notes:

  • If there's already a CLAUDE.md, suggest improvements to it.
  • When you make the initial CLAUDE.md, do not repeat yourself and do not include obvious instructions like "Provide helpful error messages to users", "Write unit tests for all new utilities", "Never include sensitive information (API keys, tokens) in code or commits".
  • Avoid listing every component or file structure that can be easily discovered.
  • Don't include generic development practices.
  • If there are Cursor rules (in .cursor/rules/ or .cursorrules) or Copilot rules (in .github/copilot-instructions.md), make sure to include the important parts.
  • If there is a README.md, make sure to include the important parts.
  • Do not make up information such as "Common Development Tasks", "Tips for Development", "Support and Documentation" unless this is expressly included in other files that you read.
  • Be sure to prefix the file with the following text:
# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
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. 10d ago First seen · 27 lines · 0 tokens per session scan C 96ad3f2b5f1c

Subscribe to this mod's changes

Agent Prompt: CLAUDE.md creation is an agent published in the GitHub repository openonion/connectonion (1,480 stars, last pushed yesterday), licensed Apache-2.0. It adds 23 tokens to every session and 381 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it C with 1 finding (hidden instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.