claude-code-system-prompts is a repository that records the system prompts, tool descriptions, agent prompts, and utility prompts used by Claude Code. It serves people who want to inspect how Claude Code structures its built-in agents and tools across releases. The catalogue instruction provides access to material documenting that workflow.
Borrowing it
Nothing to install: this file belongs to Piebald-AI/claude-code-system-prompts. 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/Piebald-AI/claude-code-system-prompts/main/CLAUDE.mdgit clone --depth 1 https://github.com/Piebald-AI/claude-code-system-promptsWrote 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/piebald-ai/claude-code-system-prompts/claude-md)<a href="https://agentmods.dev/instructions/piebald-ai/claude-code-system-prompts/claude-md"><img src="https://agentmods.dev/badge/instructions/piebald-ai/claude-code-system-prompts/claude-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/piebald-ai/claude-code-system-prompts/claude-md"><img src="https://agentmods.dev/badge/instructions/piebald-ai/claude-code-system-prompts/claude-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 | $0.00362 | $0.00362 |
| Opus 5 | $0.00181 | $0.00181 |
| Sonnet 5 | $0.00072 | $0.00072 |
| Haiku 4.5 | $0.00036 | $0.00036 |
Grade A, and why
claude-code-system-prompts 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 9d 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.
What it actually says
Claude Code System Prompts
What this repository is
System prompts extracted via script from the Claude Code npm package's compiled JavaScript source. Maintained by Piebald AI, not by Anthropic.
See the Extraction section in README.md for details on the extraction method.
What Claude Code is
Claude Code is Anthropic's CLI tool for agentic coding. It is distributed as a compiled npm package (@anthropic-ai/claude-code). Source code is not publicly available. The anthropics/claude-code GitHub repository contains issues and releases only.
How to use these files
- Reference: Understand what prompts Claude Code uses and how they change across versions
- Local patching: Use tweakcc to customize individual prompt pieces in your local Claude Code installation
- Feature requests: For changes to Claude Code's prompts, file issues at anthropics/claude-code/issues
For AI agents working with this repository
- These files are extracted reference material, not modifiable source code
- Editing files here does not change Claude Code's behavior
- The
system-prompts/directory contains markdown files with YAML frontmatter noting the Claude Code version and template variables - Template variables like
${BASH_TOOL_NAME}are interpolated at runtime by Claude Code — they appear as literal strings in these files - The CHANGELOG.md tracks prompt changes across Claude Code versions
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.
- 9d ago First seen · 26 lines · 362 tokens per session scan A 6fb0cae37ab2
claude-code-system-prompts CLAUDE.md is an instructions file published in the GitHub repository Piebald-AI/claude-code-system-prompts (12,609 stars, last pushed 2d ago), licensed MIT. It adds 362 tokens to every session, about $0.0018 per session on Opus 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.
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