Fast Filesystem MCP README

Quick Start

Add to your Claude Desktop config.

• Basic setup

{
  "mcpServers": {
    "fast-filesystem": {
      "command": "npx",
      "args": ["-y", "fast-filesystem-mcp"]
    }
  }
}

• With backup files enabled

{
  "mcpServers": {
    "fast-filesystem": {
      "command": "npx",
      "args": ["-y", "fast-filesystem-mcp"],
      "env": {
        "CREATE_BACKUP_FILES": "true"
      }
    }
  }
}

Backup Configuration

Control backup file creation behavior.

• CREATE_BACKUP_FILES=false (default): Disables backup file creation to reduce clutter
• CREATE_BACKUP_FILES=true: Creates backup files before modifications

Note: Backup files are created with timestamps (e.g., file.txt.backup.1755485284402) to prevent data loss during edits.

Debug and Logging Configuration

The MCP server uses a safe logging system that prevents JSON-RPC communication errors.

• DEBUG_MCP=true or MCP_DEBUG=true: Enable debug logging to stderr
• MCP_LOG_FILE=/path/to/log.txt: Write logs to file instead of stderr
• MCP_SILENT_ERRORS=true or SILENT_ERRORS=true: Suppress error messages in responses

Note: Debug output is automatically suppressed by default to prevent JSON parsing errors in Claude Desktop.

New Version Update

To update to the latest version, follow these steps.

1. Uninstall previous version
   Terminal

   Copy

   npm uninstall -g fast-filesystem-mcp
   

2. Clean cache and dependencies
   Terminal

   Copy

   npm cache clean --force
   pnpm store prune
   

3. Install latest version
   Terminal

   Copy

   npm install -g fast-filesystem-mcp
   

4. Verify installation
   Terminal

   Copy

   npm list -g fast-filesystem-mcp
   fast-filesystem-mcp --version
   

Features

Core File Operations

• Fast File Reading/Writing: Optimized for Claude Desktop with chunking support
• Sequential Reading: Read large files completely with continuation token support
• Large File Handling: Stream-based writing for files of any size
• Directory Operations: Comprehensive directory listing, creation, and management
• File Search: Name and content-based file searching with filtering

Advanced Capabilities

• Pagination Support: Handle large directories efficiently
• Chunked Reading: Read large files in manageable chunks
• Streaming Writes: Memory-efficient writing for large files
• Backup & Recovery: Automatic backup creation and error recovery
• Retry Logic: Built-in retry mechanism for reliable operations

Performance Optimizations

• Claude-Optimized: Response sizes and formats optimized for Claude
• Memory Efficient: Streaming operations prevent memory overflow
• Smart Exclusions: Automatically excludes system files and directories
• Progress Tracking: Real-time progress monitoring for large operations

Available Tools

File Operations

Complex File Management

Archive Management

Directory Synchronization

Advanced Editing Tools

Directory Operations

Search Operations

System Operations

Editing Tools

Precise File Editing

The fast-filesystem MCP now includes powerful editing tools for source code and text files.

fast_edit_file - Single Block Editing

Supports multiple editing modes.

• replace: Replace text or entire lines
• replace_range: Replace multiple lines at once
• insert_before: Insert content before specified line
• insert_after: Insert content after specified line
• delete_line: Delete specific lines

{
  "tool": "fast_edit_file",
  "arguments": {
    "path": "/path/to/file.js",
    "mode": "replace",
    "line_number": 10,
    "new_text": "const newVariable = 'updated value';",
    "backup": true
  }
}

fast_edit_multiple_blocks - Batch Editing

Edit multiple parts of a file in a single operation.

{
  "tool": "fast_edit_multiple_blocks", 
  "arguments": {
    "path": "/path/to/file.js",
    "edits": [
      {
        "mode": "replace",
        "old_text": "oldFunction()",
        "new_text": "newFunction()"
      },
      {
        "mode": "insert_after",
        "line_number": 5,
        "new_text": "// Added comment"
      }
    ],
    "backup": true
  }
}

fast_extract_lines - Line Extraction

Extract specific lines by number, range, or pattern.

{
  "tool": "fast_extract_lines",
  "arguments": {
    "path": "/path/to/file.js",
    "pattern": "function.*",
    "context_lines": 2
  }
}

fast_search_and_replace - Advanced Replace

Powerful search and replace with regex support.

{
  "tool": "fast_search_and_replace",
  "arguments": {
    "path": "/path/to/file.js", 
    "search_pattern": "console\\.log\\(.*\\)",
    "replace_text": "logger.info($1)",
    "use_regex": true,
    "max_replacements": 10,
    "backup": true
  }
}

Editing Features

• Automatic Backup: Creates backups before modifications
• Error Recovery: Restores from backup on failure
• Line-based Operations: Precise control over specific lines
• Pattern Matching: Regular expression support
• Batch Operations: Multiple edits in single transaction
• Context Extraction: Extract lines with surrounding context

Large File Writing

• fast_large_write_file
  • Streaming: Writes files in chunks to prevent memory issues
  • Backup: Automatically creates backups before overwriting
  • Verification: Verifies file integrity after writing
  • Retry Logic: Automatic retry on failure with exponential backoff
  • Progress Tracking: Real-time monitoring of write progress

License

Apache 2.0

Copyright 2025 efforthye

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Repository

https://github.com/efforthye/fast-filesystem-mcp