Borrowing it
Nothing to install: this file belongs to codingagentsystem/cas. 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/codingagentsystem/cas/main/CLAUDE.mdgit clone --depth 1 https://github.com/codingagentsystem/casWrote 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/codingagentsystem/cas/claude-md)<a href="https://agentmods.dev/instructions/codingagentsystem/cas/claude-md"><img src="https://agentmods.dev/badge/instructions/codingagentsystem/cas/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/codingagentsystem/cas/claude-md"><img src="https://agentmods.dev/badge/instructions/codingagentsystem/cas/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 | $0.02157 | $0.02157 |
| Opus 5.5 | $0.00863 | $0.00863 |
| Sonnet 5.5 | $0.00431 | $0.00431 |
| Haiku 4.5 | $0.00216 | $0.00216 |
Grade A, and why
cas 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 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.
How it starts
The opening of the file, as written. The whole thing — 271 lines — stays where its author put it; the contents beside it link to each section on GitHub.
IMPORTANT: USE CAS FOR TASK AND MEMORY MANAGEMENT
DO NOT USE BUILT-IN TOOLS (TodoWrite, EnterPlanMode) FOR TASK TRACKING.
Use CAS MCP tools instead:
mcp__cas__taskwith action: create - Create tasks (NOT TodoWrite)mcp__cas__taskwith action: start/close - Manage task statusmcp__cas__taskwith action: ready - See ready tasksmcp__cas__memorywith action: remember - Store memories and learningsmcp__cas__searchwith action: search - Search all context
CAS provides persistent context across sessions. Built-in tools are ephemeral.
CAS - Coding Agent System
Unified context system for AI agents: persistent memory, tasks, rules, and skills across sessions.
Design Philosophy: CAS is built for AI agents as the primary users. Humans are observers who review agent activity, provide feedback, and guide direction - but the tools and workflows are optimized for agent consumption and production.
Use CAS for Task & Memory Management
Agents use CAS MCP tools instead of built-in TodoWrite:
mcp__cas__task action=create - Create/track tasks
mcp__cas__task action=start - Start working on a task (sets status to in_progress)
mcp__cas__task action=notes - Add progress notes (progress, blocker, decision, discovery)
mcp__cas__task action=close - Complete tasks
mcp__cas__memory action=remember - Store learnings and context
mcp__cas__search action=search - Find relevant context (filter with doc_type: entry/task/rule/skill)
Human CLI:
cas init # Initialize CAS in a project
cas serve # Start MCP server
cas config list # View configuration
cas doctor # Run diagnostics
cas update # Self-update
Project Structure
cas-cli/ # Rust CLI & MCP server (primary)
crates/ # Workspace crates (cas-core, cas-store, cas-search, etc.)
cas-cli Architecture
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 · 271 lines · 2,157 tokens per session scan A e73b9d5e8319
cas CLAUDE.md is an instructions file published in the GitHub repository codingagentsystem/cas (177 stars, last pushed 7mo ago), licensed MIT. It adds 2,157 tokens to every session, about $0.0086 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 2026-08-30.
cas CLAUDE.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| cas CLAUDE.mdcodingagentsystem/cas | Instructions file | 177 | 7mo ago | MIT | A | 2,157 | Claude Code |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | today | 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 |