filesystem-slim

> Filesystem MCP server optimized for AI assistants — Reduce context window tokens by 62.7% while keeping full functionality. Compatible with Claude, ChatGPT, Gemini, Cursor, and all MCP clients.


What is filesystem-slim?

A token-optimized version of the Filesystem Model Context Protocol (MCP) server.

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MCP tool schemas consume significant context window tokens. When AI assistants like Claude or ChatGPT load MCP tools, each tool definition takes up valuable context space.

The original @modelcontextprotocol/server-filesystem loads 14 tools consuming approximately ~10,563 tokens — that's space you could use for actual conversation.

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filesystem-slim intelligently groups 14 tools into 6 semantic operations, reducing token usage by 62.7% — with zero functionality loss.

Your AI assistant sees fewer, smarter tools. Every original capability remains available.

Performance

| Metric | Original | Slim | Reduction |
|--------|----------|------|-----------|
| Tools | 14 | 6 | -54% |
| Schema Tokens | 2,583 | 518 | 79.9% |
| Claude Code (est.) | ~10,563 | ~3,938 | ~62.7% |

> Benchmark Info
> - Original: @modelcontextprotocol/server-filesystem@2025.12.18
> - Schema tokens measured with tiktoken (cl100k_base)
> - Claude Code estimate includes ~570 tokens/tool overhead

Quick Start

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``bash


Claude Desktop - auto-configure

npx filesystem-slim --setup claude

Cursor - auto-configure

npx filesystem-slim --setup cursor

Interactive mode (choose your client)

npx filesystem-slim --setup
`

Done! Restart your app to use filesystem.

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`bash


Claude Code (creates .mcp.json in project root)

claude mcp add filesystem -s project -- npx -y filesystem-slim@latest

Windows: use cmd /c wrapper

claude mcp add filesystem -s project -- cmd /c npx -y filesystem-slim@latest

VS Code (Copilot, Cline, Roo Code)

code --add-mcp '{"name":"filesystem","command":"npx","args":["-y","filesystem-slim@latest"]}'
`

Manual Setup

Click to expand manual configuration options

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Add to your claude_desktop_config.json:

| OS | Path |
|----|------|
| Windows | %APPDATA%\Claude\claude_desktop_config.json |
| macOS | ~/Library/Application Support/Claude/claude_desktop_config.json |

`json
{
"mcpServers": {
"filesystem": {
"command": "npx",
"args": ["-y", "filesystem-slim@latest"]
}
}
}
`

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Add to .cursor/mcp.json (global) or /.cursor/mcp.json (project):

`json
{
"mcpServers": {
"filesystem": {
"command": "npx",
"args": ["-y", "filesystem-slim@latest"]
}
}
}
`

How It Works

MCPSlim acts as a transparent bridge between AI models and the original MCP server:

`
┌─────────────────────────────────────────────────────────────────┐
│ Without MCPSlim │
│ │
│ [AI Model] ──── reads 14 tool schemas ────→ [Original MCP] │
│ (~10,563 tokens loaded into context) │
├─────────────────────────────────────────────────────────────────┤
│ With MCPSlim │
│ │
│ [AI Model] ───→ [MCPSlim Bridge] ───→ [Original MCP] │
│ │ │ │ │
│ Sees 6 grouped Translates to Executes actual │
│ tools only original call tool & returns │
│ (~3,938 tokens) │
└─────────────────────────────────────────────────────────────────┘
`

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1. AI reads slim schema — Only 6 grouped tools instead of 14
2. AI calls grouped tool — e.g., interaction({ action: "click", ... })
3. MCPSlim translates — Converts to original: browser_click({ ... })
4. Original MCP executes — Real server processes the request
5. Response returned — Result passes back unchanged

Zero functionality loss. 62.7% token savings.

Available Tool Groups

| Group | Actions |
|-------|---------|
| create | 2 |
| delete | 2 |
| file | 3 |
| move | 2 |
| query | 2 |
| read | 2 |

Compatibility

- ✅ Full functionality — All original @modelcontextprotocol/server-filesystem features preserved
- ✅ All AI assistants — Works with Claude, ChatGPT, Gemini, Copilot, and any MCP client
- ✅ Drop-in replacement — Same capabilities, just use grouped action names
- ✅ Tested — Schema compatibility verified via automated tests

FAQ

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No. Every original tool is accessible. Tools are grouped semantically (e.g., click, hover, drag → interaction), but all actions remain available via the action` parameter.

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AI models have limited context windows. MCP tool schemas consume tokens that could be used for conversation, code, or documents. Reducing tool schema size means more room for actual work.

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MCPSlim is a community project. It wraps official MCP servers transparently — the original server does all the real work.

License

MIT

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Powered by MCPSlim — MCP Token Optimizer


_{Reduce AI context usage. Keep full functionality.}