fast-filesystem-mcp

A high-performance Model Context Protocol (MCP) server that provides secure filesystem access and AI-optimized code development tools for Claude and other AI assistants.

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

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

- 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.

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

- DEBUG_MCP=trueorMCP_DEBUG=true: Enable debug logging to stderr
- MCP_LOG_FILE=/path/to/log.txt: Write logs to file instead of stderr
- MCP_SILENT_ERRORS=trueorSILENT_ERRORS=true: Suppress error messages in responses

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

To update to the latest version, follow these steps.
- Uninstall previous version

npm uninstall -g fast-filesystem-mcp

npm cache clean --force pnpm store prune

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

- 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

- 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

- 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

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

- 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 } }

Extract specific lines by number, range, or pattern.

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

{ "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 } }

- 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

- 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

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.

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

A secure server for filesystem operations with controlled access to specified directories.