Ctxbleach
FreeNot checkedLocal CLI and MCP server that redacts secrets from logs, files, and diffs before sending them to AI agents, with stable placeholders and token-budgeted truncati
About
Local CLI and MCP server that redacts secrets from logs, files, and diffs before sending them to AI agents, with stable placeholders and token-budgeted truncation.
README
ctxbleach
Local CLI and MCP server that bleaches secrets from logs, files, and diffs before AI agents see them.

🎯 Why?
Trending agent-context projects focus on giving agents more code and memory, while guardrail tools mostly block commands. Developers still need a tiny local middleware that transforms raw logs, env files, and command output into safe, token-budgeted context before it reaches an LLM. Existing secret scanners are CI-oriented and do not provide interactive redaction placeholders, MCP tools, or context budgeting.
Target audience: Developers and platform engineers using Claude Code, Cursor, Codex, or MCP-enabled agents who need to share logs, .env files, stack traces, and CI output without leaking credentials.
✨ Features
- ✨ Regex-based redaction for AWS keys, GitHub/Slack tokens, JWTs, bearer headers, URL passwords, private keys, and generic secret assignments
- ✨ Stable placeholders and masked scan output so no secret values are echoed back
- ✨ Token-budgeted truncation with head or tail preservation for large logs
- ✨ CLI commands for scan, redact, and MCP stdio serving
- ✨ Zero-dependency Python implementation that can be dropped into agent workflows
🚀 Quick Start
# Install
pip install ctxbleach
# Run
ctxbleach --help
📦 Installation
From Source
git clone https://github.com/YOUR_USERNAME/ctxbleach.git
cd ctxbleach
# Create virtual environment
python -m venv .venv
source .venv/bin/activate # Windows: .venv\Scripts\activate
# Install in development mode
pip install -e ".[dev]"
# Run tests
pytest -v
🎬 Demo
The GIF above was recorded using Charm VHS:
vhs < demo.tape
📖 Usage
# Show help
ctxbleach --help
# Common usage examples
ctxbleach --example
🏗️ Architecture
graph LR
A[Input] --> B[Core Engine]
B --> C[Output]
B --> D[Plugins]
D --> E[Extensions]
🤝 Contributing
Contributions are welcome! Please:
- Fork the repo
- Create a feature branch (
git checkout -b feature/amazing-feature) - Commit your changes (
git commit -m 'Add amazing feature') - Push to the branch (
git push origin feature/amazing-feature) - Open a Pull Request
📄 License
MIT © 2026 — See LICENSE for details.
If this project helped you, please ⭐ star it!
Installing Ctxbleach
This server has no published package — it is built from source. Open the repository and follow its README.
▸ github.com/yulinlina/ctxbleachFAQ
Is Ctxbleach MCP free?
Yes, Ctxbleach MCP is free — one-click install via Unyly at no cost.
Does Ctxbleach need an API key?
No, Ctxbleach runs without API keys or environment variables.
Is Ctxbleach hosted or self-hosted?
Self-hosted: the server runs locally on your machine via the install command above.
How do I install Ctxbleach in Claude Desktop, Claude Code or Cursor?
Open Ctxbleach on unyly.org, pick your client tab (Claude Desktop, Claude Code, Cursor) and press Install — the config is generated automatically, no JSON editing.
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