fs-mcp 1.9.2

A secure MCP filesystem server with Stdio and Web UI modes.

fs-mcp 📂

The "Human-in-the-Loop" Filesystem MCP Server

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https://github.com/user-attachments/assets/132acdd9-014c-4ba0-845a-7db74644e655

💡 Why This Exists

I built this because I was tired of jumping through hoops.

The promise of the Model Context Protocol (MCP) is incredible, but the reality of using the standard filesystem server hit a few walls for my workflow:

1. The Container Gap: I do most of my work in Docker. Connecting a local agent (like Claude Desktop) to a filesystem inside a container via Stdio is a networking nightmare.
2. The Free Tier Lockout: I wanted to use the free tier of Google AI Studio to edit code, but you can't easily plug MCP into a web interface.
3. Schema Hell: Even if you do copy-paste schemas into Gemini, they often break because Gemini's strict validation is only a subset of the standard OpenAPI spec.

fs-mcp solves this. It is a Python-based server built on fastmcp that treats "Human-in-the-Loop" as a first-class citizen, enabling seamless and interactive collaboration between LLM agents and a developer's local environment.

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🚀 Key Features

1. HTTP by Default (Remote Ready)

It runs a background HTTP server alongside the CLI. You can finally connect agents to remote environments or containers without SSH tunneling wizardry.

2. Zero-Config Inspector

No npm install inspector. I baked a Streamlit Web UI directly into the package. Launch it, and you instantly have a visual form to test tools, view results, and generate configs.

3. Copy-Paste Gemini Schemas 📋

The UI automatically sanitizes and translates your tool schemas specifically for Google GenAI. It strips forbidden keys (default, title, etc.) so you can paste function definitions directly into AI Studio and start coding for free.

4. Human-in-the-Loop Diffing 🤝

The propose_and_review tool bridges the gap between agent proposals and human oversight. It opens a VS Code diff window for you to inspect changes.

How it Works:

1. The agent calls propose_and_review with a code change.
2. A VS Code window pops up showing the Diff.
3. To Approve: Add a double newline at the very end of the file and Save.
4. To Review: Just edit the code directly in the diff window and Save. The agent will receive your edits as feedback and try again!

sequenceDiagram
    participant User
    participant Agent
    participant MCP_Server

    User->>Agent: "Propose an edit to README.md"
    activate Agent
    Agent->>MCP_Server: call propose_and_review(path="README.md", old, new)
    activate MCP_Server
    Note right of MCP_Server: Creates temp files & prints vscode_command.<br/>Now enters "watch loop", waiting for user to save.
    MCP_Server-->>User: (via console) `code --diff ...`
    
    Note right of User: User opens VS Code, is happy with the change,<br/>adds a double newline to the end of the file, and saves.
    
    Note right of MCP_Server: Save detected! Checks file content.
    MCP_Server-->>Agent: return { user_action: "APPROVE", message: "User approved. Call commit_review." }
    deactivate MCP_Server

    Note right of Agent: Agent sees "APPROVE" and knows what to do next.
    Agent->>MCP_Server: call commit_review(session_path, original_path="README.md")
    activate MCP_Server
    Note right of MCP_Server: Copies 'future' file to original path,<br/>removes the trailing newlines,<br/>and cleans up the temp directory.
    MCP_Server-->>Agent: return "Successfully committed changes."
    deactivate MCP_Server
    
    Agent-->>User: "Changes have been committed!"
    deactivate Agent

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⚡ Quick Start

Run Instantly

By default, this command launches the Web UI (8123) and a Background HTTP Server (8124).

# Allow access to the current dir
uvx fs-mcp .

Selective Launch

Want to disable a component? Use the flags:

# UI Only (No background HTTP)
fs-mcp --no-http .

# HTTP Only (Headless / Docker mode)
fs-mcp --no-ui .

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🔌 Configuration

Claude Desktop (Stdio Mode)

Add this to your claude_desktop_config.json:

{
  "mcpServers": {
    "fs-mcp": {
      "command": "uvx",
      "args": [
        "fs-mcp",
        "/absolute/path/to/your/project"
      ]
    }
  }
}

Docker (HTTP Mode)

To run inside a container and expose the filesystem to a local agent:

# In your entrypoint or CMD
uvx fs-mcp --no-ui --http-host 0.0.0.0 --http-port 8124 /app

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The Toolbox 🧰

Tool	Description
propose_and_review	Interactive Review: Opens VS Code diff. Add a double newline to finalize.
commit_review	Finalizes the changes from an interactive review session.
read_multiple_files	Reads content of multiple files to save context window.
directory_tree	Fast: Returns recursive JSON tree. Skips .venv/.git automatically.
search_files	Recursive pattern discovery using rglob.
grounding_search	New: Natural language query for grounded search results.
read_text_file	Standard text reader (supports head/tail for large files).
list_directory_with_sizes	Detailed listing including formatted file sizes.
list_allowed_directories	List security-approved paths.
get_file_info	Metadata retrieval (size, modified time).
read_media_file	Returns base64 encoded images/audio.
write_file	Creates or overwrites files (atomic operations).
create_directory	Create a new directory.
move_file	Move or rename files.
append_text	Safe fallback for appending content to EOF.

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License & Credits

Built with ❤️ for the MCP Community by luutuankiet. Powered by FastMCP and Streamlit.

Now go build some agents. 🚀