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Filesystem Context

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Secure, read-only filesystem exploration and analysis

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Secure, read-only filesystem exploration and analysis

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Filesystem MCP

Let your AI assistant work with your files, safely.

Read, search, edit, and patch files in the folders you choose.
Secret files stay hidden, and risky changes wait for your OK.

npm version CI License: MIT GitHub stars HOL Trust

Install in VS Code Install in VS Code Insiders Install in Visual Studio Install in Cursor Install in Claude Desktop

What is this?

Model Context Protocol (MCP) is how AI apps such as Claude, GitHub Copilot in VS Code, and Cursor connect to tools. Filesystem MCP is an MCP server: a small program that runs on your computer and gives the AI 14 tools for working with files. You choose which folders it can use, and everything outside them is off limits.

Once it is connected, you can ask things like:

  • "Find every TODO in this repo and group them by file."
  • "Rename getUser to fetchUser in all .ts files. Show me the diff first."
  • "What changed between config.dev.json and config.prod.json?"
  • "Read the last 50 lines of server.log and explain the error."
  • "Move the old screenshots into archive/2025/."

Why Filesystem MCP?

  • It is safe by default. The AI can use only the folders you allow, and .env files, private keys, and cloud credentials are blocked. The server asks you before the AI deletes a non-empty folder, opens a folder you did not allow, or writes over a file with create or move. Only create and copies can skip that question, by passing overwrite: true. Edits made with edit, patch, and replace_text apply without asking, but the AI can show you the diff first with dryRun. If the AI should never change anything, --read-only removes every tool that writes.
  • Search and editing are made for code. The AI can search inside files like grep, with a regex engine (RE2) that cannot hang, and by default the server skips .gitignored files and folders like node_modules. Edits are exact-match replacements that return an error when the text does not match, and you can preview them as a diff first.
  • It saves the AI's context. The AI can read many files in one call or only the lines it needs, and it can check a file's size and token estimate before reading it.
  • It works with any MCP client, over stdio or HTTP, on macOS, Linux, and Windows. You can install it with npx, Docker, or a one-click Claude Desktop extension, or build your own client on it.
  • It is private. It runs on your machine, has no telemetry, and makes no network calls.

Compared with the reference server

How this server differs from the official @modelcontextprotocol/server-filesystem, checked against its README on 2026-10-11:

Capability Filesystem MCP Reference server
Search inside files search_text: literal text or RE2 regex None; search_files matches names only
Secret files .env, keys, and credentials blocked by default Not blocked
Overwriting a file create asks you first (unless overwrite: true) write_file overwrites without asking
Delete files delete; asks before deleting a non-empty folder None
.gitignore Respected by listing and search tools Not supported
Read-only mode --read-only removes every tool that writes Docker ro mounts only
Apply a unified diff patch None
Compare two files diff None
Replace across many files replace_text over a folder or glob None
Watch files Subscribe to a file and get change notifications None
Transport stdio, or Streamable HTTP with --port stdio

Quick start

[!NOTE] You need Node.js 24 or later. Check with node --version.

  1. Add the server to your AI app. Pick yours below.
  2. Replace /path/to/project with the folder the AI may use. You can list several folders.
  3. Restart the app and ask: "Which folders can you access?"

[!TIP] VS Code currently shares the folders you have open with the server, so the one-click VS Code install works without a path. In other apps, or over HTTP, put the folder in args. If the AI says it has no folders, that is the fix.

VS Code

Click Install in VS Code above, or add this to .vscode/mcp.json:

{
  "servers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@j0hanz/filesystem-mcp@latest", "/path/to/project"]
    }
  }
}

Or from a terminal:

code --add-mcp '{"name":"filesystem","command":"npx","args":["-y","@j0hanz/filesystem-mcp@latest","/path/to/project"]}'
Cursor

Click Install in Cursor above, then add your folder to args. Or add this to .cursor/mcp.json in your project, or ~/.cursor/mcp.json for all projects:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@j0hanz/filesystem-mcp@latest", "/path/to/project"]
    }
  }
}
Claude Desktop

For a one-click install, download filesystem-mcp.mcpb, open it with Claude Desktop, and pick the folders to allow. Claude Desktop's built-in Node.js runs it. The extension's settings also let you turn on read-only mode and block more files.

To set it up by hand, add this to claude_desktop_config.json (Settings → Developer → Edit Config):

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@j0hanz/filesystem-mcp@latest", "/path/to/project"]
    }
  }
}
Claude Code
claude mcp add filesystem -- npx -y @j0hanz/filesystem-mcp@latest /path/to/project

Or install the plugin, which points the server at your current project:

/plugin marketplace add j0hanz/j0hanz-marketplace
/plugin install filesystem-mcp@j0hanz-marketplace
Visual Studio

Add this to .vs\mcp.json in your solution folder, or %USERPROFILE%\.mcp.json for all solutions:

{
  "servers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@j0hanz/filesystem-mcp@latest", "C:/path/to/project"]
    }
  }
}
GitHub Copilot CLI and Antigravity CLI (plugin)

The filesystem-mcp plugin sets the server up for your current project:

Client Install
Copilot CLI copilot plugin marketplace add j0hanz/j0hanz-marketplace, then copilot plugin install filesystem-mcp@j0hanz-marketplace
Antigravity CLI git clone https://github.com/j0hanz/j0hanz-marketplace, then agy plugin install ./j0hanz-marketplace/plugins/filesystem-mcp
Docker

The container can only see the folders you mount. This setup blocks writes twice, with the :ro mount and with the --read-only flag.

{
  "mcpServers": {
    "filesystem": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-v",
        "/path/to/project:/workspace:ro",
        "ghcr.io/j0hanz/filesystem-mcp:latest",
        "--read-only",
        "/workspace"
      ]
    }
  }
}

Drop :ro and --read-only to let the AI make changes. VS Code and Visual Studio use "servers" instead of "mcpServers". See Running in Docker for more.

Other MCP clients

Windsurf, Cline, and most other clients use the same mcpServers JSON as Claude Desktop above. In any client, the server is:

  • command: npx
  • args: -y, @j0hanz/filesystem-mcp@latest, then one or more folders

You can also install it globally and run filesystem-mcp /path/to/project:

npm install -g @j0hanz/filesystem-mcp

Tools

Tool What it does
list_roots Shows the folders the server may use.
list Lists a folder as a tree, like ls or tree.
find_files Finds files by name or glob, such as **/*.test.ts.
search_text Searches inside files for text or a regex, like grep, with optional context lines.
stat Gets size, dates, type, permissions, and a token estimate without reading the file.
read Reads text files whole or by lines, head, or tail. Images and audio come back as media; others with binary.
diff Compares two files and returns a unified diff.
create ✎ Writes new files, appends, or makes empty folders. Asks before replacing a file, unless overwrite: true.
edit ✎ Replaces exact text in files. All edits to a file apply, or none do. dryRun shows the diff first.
patch ✎ Applies a unified diff to a file. All hunks apply, or none do.
replace_text ✎ Finds and replaces text or a regex across many files. dryRun shows what would change.
move ✎ Moves, renames, or copies files and folders. Asks before overwriting, unless a copy passes overwrite: true.
delete ✎ Deletes files and folders. Asks before deleting a non-empty folder.
undo ✎ Reverts earlier changes by undo id or the last N calls, while the server runs. Skips files changed since.

✎ changes files. --read-only removes these tools.

Search and listing tools skip hidden files, .gitignored files, and folders like node_modules, dist, and .git unless the AI asks for them.

Configuration

Most people only need the folder argument. These options cover the common cases:

Option What it does
--read-only Removes every tool that changes files.
--deny '<pattern>' Blocks more files, for example --deny 'private/**' or --deny '*.sqlite'.
--allow '<pattern>' Unblocks one built-in secret pattern, for example --allow '.env.example'.
--allow-cwd Also allows the folder the server was started from.
--max-file-size <n> Largest file read will load, in bytes. Default 10 MiB.
--port <n> Serves over HTTP at http://127.0.0.1:<n>/mcp instead of stdio.
--print-config Prints the settings the server would use, then exits.

Flags go in args after the package name, for example ["-y", "@j0hanz/filesystem-mcp@latest", "--read-only", "/path/to/project"].

The full configuration reference covers every flag and environment variable, the complete secret-file list, limits, HTTP setup with API keys, Docker, and troubleshooting.

Security

Protection How it works
Folder sandbox The server resolves every path, including symlinks, and the resolved path must stay inside an allowed folder.
Secret files .env, *.pem, *.key, SSH keys, .npmrc, cloud credentials, and more are blocked and hidden from listings.
You stay in charge The server asks you before the AI deletes a non-empty folder, gets access to a new folder, or writes over a file with create or move. Only create and copies skip that question, when the AI passes overwrite: true. In-place edits (edit, patch, replace_text) do not ask, but dryRun previews them. A client that cannot ask gets an error instead.
Off-limits folders Neither the AI nor the client can ever add your home folder itself, system folders, or ~/.ssh, ~/.aws, and similar folders.
Safe writes New content goes to a temporary file that is then renamed into place, so a crash never leaves a half-written file. Writes keep the file's permissions.
No regex hangs RE2 runs in linear time, so no search pattern can freeze the server.
HTTP The server listens only on localhost by default. Any other address requires an API key.
Container The Docker image runs as a non-root user.

If you find a vulnerability, please report it privately. SECURITY.md explains how.

Build your own client

You can also call Filesystem MCP from your own code: an agent, an editor plugin, a web app, a CI job, or a script. The same rules apply as for an AI app, so your code cannot reach outside the allowed folders or read secret files.

import { Client } from '@modelcontextprotocol/client';
import { StdioClientTransport } from '@modelcontextprotocol/client/stdio';

const dir = '/path/to/project';
const client = new Client(
  { name: 'my-app', version: '1.0.0' },
  { capabilities: { elicitation: { form: {} } }, versionNegotiation: { mode: 'auto' } },
);
client.setRequestHandler('elicitation/create', async () => ({ action: 'decline' }));
await client.connect(
  new StdioClientTransport({
    command: 'npx',
    args: ['-y', '@j0hanz/filesystem-mcp', dir],
    cwd: dir,
  }),
);

const result = await client.callTool({ name: 'search_text', arguments: { searchPattern: 'TODO' } });
const { matches } = (result.structuredContent ?? result._meta) as { matches: unknown[] };
console.log(matches);
await client.close(); // stops the server process; without it the script never exits

The basics:

  • Where the data is. The text block is written for a model. The same data as JSON is in _meta for tools that write their own text (list, search_text, edit, ...) and in structuredContent for stat, create, and list_roots. read is the exception: the file's text is only in the text block, and _meta holds metadata about it.
  • Paths. A relative path resolves against the server's working directory when that is inside a root, and against the root otherwise. With several roots, it must exist under exactly one of them. Absolute paths are never ambiguous. Search results are printed relative to the root, so a result can be passed straight back. A name that differs from the one on disk only in Unicode form (NFC or NFD) or in its space characters (U+00A0, U+202F) finds that entry.
  • Confirmations. Overwrites, recursive deletes, and paths outside the roots are questions for the user. Declare the elicitation capability and answer them in a handler, or, on the 2026-07-28 protocol, take them as data (input_required) and answer later.
  • Protocol versions. The server speaks the 2025 protocol and 2026-07-28, over stdio and Streamable HTTP. Over HTTP, 2025-era clients get no confirmations or change notifications.
  • Resources. Read and subscribe to any file as filesystem-mcp://file/{+path}; internal://instructions and the get-help prompt hold the server's guide for models.

The client guide has the details, tested with the TypeScript and Python SDKs, and examples/ has six runnable clients:

Example What it is
fsq Any tool from your shell, over stdio or HTTP; --json for scripts
browser A local web UI where the server's questions appear in the page
tail tail -f through file subscriptions, locally or on a remote server
gatekeeper A coding agent that shows each change's diff and waits for your y/N
hooks Runs a task through a model whenever the workspace changes
python A TODO report for a workspace, with the Python SDK

Privacy policy

Filesystem MCP runs entirely on your machine. This policy covers the npm package, the Docker image, and the .mcpb desktop extension.

  • Data collection: none. The server has no telemetry, analytics, or crash reporting, and makes no outbound network requests.
  • Use and storage: the server reads and writes files only inside the folders you allow, and only when your MCP client calls a tool. Tool results go to that client and nowhere else. Short-lived result caches and the undo history (saved file contents) live in memory and disappear when the server exits.
  • Third-party sharing: none by this server. Your MCP client may send tool results to its model provider under that client's own privacy policy.
  • Retention: the server keeps nothing after the process exits. Diagnostic logs go to stderr on your machine; your MCP client may save them in its own log files.
  • Contact: open an issue at https://github.com/j0hanz/filesystem-mcp/issues, or report security problems privately through GitHub Security Advisories.

Contributing

Bug reports, ideas, and pull requests are welcome. Start with CONTRIBUTING.md. It covers setup, running the server from source, and the checks a pull request needs.

If Filesystem MCP is useful to you, a star on GitHub helps other people find it.

Contributors

License

MIT

from github.com/j0hanz/filesystem-mcp

Install Filesystem Context in Claude Desktop, Claude Code & Cursor

Recommended · one command, every IDE
unyly install filesystem-context

Installs into Claude Desktop, Claude Code, Cursor & VS Code — handles npx, uvx and build-from-source repos for you.

First time? Get the CLI: curl -fsSL https://unyly.org/install | sh

Or configure manually

Run in your terminal:

claude mcp add filesystem-context --env FS_ALLOWED_DIRS="" --env FS_API_KEY="" --env REDIS_URL="" -- npx -y @j0hanz/filesystem-mcp

Step-by-step: how to install Filesystem Context

FAQ

Is Filesystem Context MCP free?

Yes, Filesystem Context MCP is free — one-click install via Unyly at no cost.

Does Filesystem Context need an API key?

Yes, it requires environment variables: FS_ALLOWED_DIRS, FS_API_KEY, REDIS_URL. Unyly injects them into the config during install.

Is Filesystem Context hosted or self-hosted?

Self-hosted: the server runs locally on your machine via the install command above.

How do I install Filesystem Context in Claude Desktop, Claude Code or Cursor?

Open Filesystem Context on unyly.org, pick your client tab (Claude Desktop, Claude Code, Cursor) and press Install — the config is generated automatically, no JSON editing.

Changes

Versions and requested access over time.

  • New version published
  • New version published
  • New version published
  • New version published
  • New version published
  • New version published
  • New version published
  • New version published

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