Borrowing it
Nothing to install: this file belongs to mcs-cli/mcs. 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/mcs-cli/mcs/main/CLAUDE.mdgit clone --depth 1 https://github.com/mcs-cli/mcsWrote 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/mcs-cli/mcs/claude-md)<a href="https://agentmods.dev/instructions/mcs-cli/mcs/claude-md"><img src="https://agentmods.dev/badge/instructions/mcs-cli/mcs/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/mcs-cli/mcs/claude-md"><img src="https://agentmods.dev/badge/instructions/mcs-cli/mcs/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 | $0.06562 | $0.06562 |
| Opus 5.5 | $0.02625 | $0.02625 |
| Sonnet 5.5 | $0.01312 | $0.01312 |
| Haiku 4.5 | $0.00656 | $0.00656 |
Grade B, and why
mcs CLAUDE.md scanned grade B 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 3d 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.
Reads agent configuration directoriesmediumAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
- **`mcs bootstrap` is project-scoped, additive-by-default, opt-in-authoritative**: reads `./mcs.yaml` (fixed filename, cwd only) and drives the current project's pack set. Like `mcs sync`, its non-dry-run tail refreshes How it starts
The opening of the file, as written. The whole thing — 230 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Project Overview
Swift CLI tool (mcs) that configures Claude Code with MCP servers, plugins, skills, hooks, and settings. Pure pack management engine with zero bundled content — all features come from external tech packs. Distributed via Homebrew.
Commands
# Development
swift build # Build the CLI
swift test # Run tests
swift build -c release --arch arm64 --arch x86_64 # Universal binary
# CLI usage (after install)
mcs sync [path] # Sync project: multi-select packs, compose artifacts (default command)
mcs sync --pack ios # Non-interactive: add/update specific packs (repeatable), keeping other configured packs
mcs sync --pack ios --prune # Make the named packs the exact set — removes the rest after confirmation
mcs sync --pack ios --prune --yes # Prune without the removal-confirmation prompt (CI)
mcs sync --all # Apply all registered packs without prompts
mcs sync --dry-run # Preview what would change
mcs sync --global # Sync global scope (MCP servers, brew, plugins to ~/.claude/)
mcs bootstrap # Apply ./mcs.yaml — install declared packs (additive; keeps other configured packs)
mcs bootstrap --prune # Also remove packs configured here but absent from mcs.yaml
mcs bootstrap --dry-run # Preview what would change
mcs bootstrap --prune --yes # Prune without the removal-confirmation prompt (CI)
mcs bootstrap --trust-all # Approve pack trust prompts automatically (no TTY needed)
mcs update # Fetch latest pack versions and re-apply across every configured scope
mcs update --global # Refresh only the global scope
mcs update --project # Refresh only the current project's scope
mcs update --all-projects # Refresh global + every project tracked in ~/.mcs/projects.yaml (asks confirmation)
mcs update --dry-run # Preview what would change
mcs update --trust-all # Trust changed executable content without prompting (no TTY needed)
mcs doctor # Diagnose installation health
mcs doctor --fix # Diagnose, then run fixes and re-sync scopes with repairable failures (one confirmation)
mcs doctor --pack ios # Only check a specific pack
mcs doctor --global # Check globally-configured packs only
mcs pack add <source> # Add a tech pack (git URL, GitHub shorthand, or local path)
mcs pack add user/repo # GitHub shorthand → https://github.com/user/repo.git
mcs pack add /path/to/pack # Add a local pack (read in-place, no clone)
mcs pack add <url> --ref <tag> # Add at a specific tag or branch (git only)
mcs pack add <url> --preview # Preview pack contents without installing
mcs pack remove <name> # Remove an external tech pack
mcs pack remove <name> --force # Remove without confirmation
mcs pack list # List registered external packs
mcs pack update [name] # Refresh pack registry only (low-level fetch; use 'mcs update' for fetch + apply)
mcs pack update --trust-all # Trust changed executable content without prompting (no TTY needed)
mcs pack validate [source] # Validate a tech pack (path, identifier, or current directory)
mcs cleanup # Find and delete backup files
mcs cleanup --force # Delete backups without confirmation
mcs cleanup --all-projects # Also scan every project tracked in ~/.mcs/projects.yaml
mcs export <dir> # Export current config as a tech pack
mcs export <dir> --global # Export global scope (~/.claude/)
mcs export <dir> --identifier id # Set pack identifier (prompted if omitted)
mcs export <dir> --non-interactive # Include everything without prompts
mcs export <dir> --dry-run # Preview what would be exported
mcs check-updates # Check for pack and CLI updates
mcs check-updates --hook # Run as SessionStart hook (24-hour cooldown, respects config)
mcs check-updates --json # Machine-readable JSON output
mcs check-updates --snooze # Silence the SessionStart update notice until tomorrow (local time)
mcs config list # Show all settings with current values
mcs config get <key> # Get a specific setting value
mcs config set <key> <value> # Set a configuration value (true/false)
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.
- 3d ago Changed · +58 tokens per session 5d5be3ddc837
- 6d ago Changed · +1 lines · +23 tokens per session 3021ff92e038
- 19d ago Changed · +1 lines · +206 tokens per session 865db89711a1
- 1mo ago Changed · +3 lines · +92 tokens per session 2fec969bbdca
- 1mo ago Changed · +142 tokens per session d646317237e3
- 1mo ago Changed · +2 lines · +582 tokens per session 5f5bfcb14c6d
- 1mo ago Changed · -4 tokens per session 1086682b07bf
- 1mo ago Changed · +3 lines · +353 tokens per session 42f7e4138a5d
- 1mo ago Changed · +1 lines · +21 tokens per session b5cc533f66b0
- 1mo ago First seen · 219 lines · 5,089 tokens per session scan B b85830b27357
mcs CLAUDE.md is an instructions file published in the GitHub repository mcs-cli/mcs (92 stars, last pushed 3d ago), licensed MIT. It adds 6,562 tokens to every session, about $0.0262 per session on Opus 5.5. A static security scan graded it B with 1 finding (reads agent configuration directories). 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).
vscode model-prompts.instructions.md
Model-specific prompt authoring and registry guidelines.