Fast FilesystemCAUTION
A high-performance Model Context Protocol (MCP) server that provides secure filesystem access for Claude and other AI assistants.
Overview
From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.
Advanced filesystem operations for Claude Desktop with large file handling capabilities and Claude-optimized features.
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 clutterCREATE_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=trueorMCP_DEBUG=true: Enable debug logging to stderrMCP_LOG_FILE=/path/to/log.txt: Write logs to file instead of stderrMCP_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.
New Version Update
To update to the latest version, follow these steps.
- Uninstall previous version
npm uninstall -g fast-filesystem-mcp
- Clean cache and dependencies
npm cache clean --force pnpm store prune
- Install latest version
npm i
b15349fbd3e0OBSERVED · 2026-10-07Connect
Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control.
claude mcp add fast-filesystem-mcp -- npx -y [email protected]
{
"mcpServers": {
"fast-filesystem-mcp": {
"command": "npx",
"args": [
"-y",
"[email protected]"
]
}
}
}Exposed tools (25)
15 read · 9 write · 1 destructive. Blast radius: 1 tool can delete or overwrite — an agent that can be talked into calling a tool can be talked into calling this one.
| Tool | Risk | Description |
|---|---|---|
fast_batch_file_operations | read | Performs batch operations on multiple files |
fast_compress_files | read | Compresses files or directories |
fast_copy_file | read | Copies a file or directory |
fast_create_directory | write | 디렉토리를 생성합니다 |
fast_delete_file | destructive | Deletes a file or directory |
fast_edit_block | write | Precise block editing: safely replace exact matches (desktop-commander style) |
fast_edit_blocks | write | Processes multiple precise block edits at once (array of fast_edit_block) |
fast_edit_multiple_blocks | write | Edits multiple parts of a file at once |
fast_extract_archive | read | Extracts an archive file |
fast_extract_lines | read | Extracts specific lines from a file |
fast_find_large_files | read | 큰 파일들을 찾습니다 |
fast_get_directory_tree | read | 디렉토리 트리 구조를 가져옵니다 |
fast_get_disk_usage | read | 디스크 사용량을 조회합니다 |
fast_get_file_info | read | 파일/디렉토리 상세 정보를 조회합니다 |
fast_large_write_file | write | Reliably writes large files (with streaming, retry, backup, and verification features) |
fast_list_allowed_directories | read | 허용된 디렉토리 목록을 조회합니다 |
fast_list_directory | read | 디렉토리 목록을 조회합니다 (페이징 지원) |
fast_move_file | write | Moves or renames a file or directory |
fast_read_file | read | 파일을 읽습니다 (청킹 지원) |
fast_read_multiple_files | read | Reads the content of multiple files simultaneously (supports sequential reading) |
fast_safe_edit | write | Safe smart editing: Detects risks and provides interactive confirmation |
fast_search_code | read | Searches for code (ripgrep-style) - provides auto-chunking, line numbers, and context |
fast_search_files | read | 파일을 검색합니다 (이름/내용) |
fast_sync_directories | write | Synchronizes two directories |
fast_write_file | write | 파일을 쓰거나 수정합니다 |
Trust audit
CAUTIONgrade B · trust 86/100 Install with care. The audit found things worth knowing before you trust its output.
| Layer | What it checks | Result |
|---|---|---|
| L0 | Provenance & inventory | WARN |
| L1 | Static analysis of the code | WARN |
| L2 | Instruction surface (what it tells the agent) | PASS |
| L3 | Class-specific surface | WARN |
| L4 | Behavioural (sandbox) | SKIPPED |
What the source does
- Filesystem
- declared (4 observation(s))
- Network
- declared (4 observation(s))
- Shell
- none-observed
- Dependencies
- not all pinned
- Secrets in source
- none-found
Findings (9)
.DS_Store
console.log(` Console.log: ${timePerOp(consoleTime)}μs`);console.log(` Logger (DEBUG=false): ${timePerOp(loggerOffTime)}μs`);console.log(` Logger (DEBUG=true): ${timePerOp(loggerOnTime)}μs`);console.log(` Logger (File): ${timePerOp(loggerFileTime)}μs\n`);fast_delete_file
.DS_Store
.vercelignore
@modelcontextprotocol/sdk, @vscode/ripgrep, @types/node, tsx, typescript
Gates applied: no_behavioural_pass.
b15349fbd3e0full audit observations/trust-audit/mcp-server/efforthye__fast-filesystem.json · Report an issue / request a re-scanAudit history
Every audit this server has had. A grade with a past is a grade somebody is still checking.
| Date | Source | Verdict | Grade | Score | Change |
|---|---|---|---|---|---|
| 2026-10-07 | b15349fbd3e0 | CAUTION | B | 86 | first audit |
Questions
What is the Fast Filesystem MCP server?
A high-performance Model Context Protocol (MCP) server that provides secure filesystem access for Claude and other AI assistants.
What tools does Fast Filesystem expose?
25 in total: 15 read-only, 9 that write, and 1 that can delete or overwrite (fast_delete_file). Every one is listed on this page with its risk.
Is Fast Filesystem safe to connect to an agent?
With care. The audit graded it B (86/100) and found 9 things worth knowing before you trust this server, listed below with the exact line each was found on. Separately from the audit: 1 of its tools can destroy data, so scope the token you give it to what you actually need.
What credentials does Fast Filesystem need?
No credential environment variables were found in its source, so it appears to need none.
How does Fast Filesystem run?
It speaks stdio and streamable-http, so it runs as a local process your client starts. It is published on npm as fast-filesystem-mcp at 3.5.2.
How current is this page?
The grade is for one exact copy of the source (b15349fbd3e0), read on 2026-10-07. The repository is watched and re-audited when it changes.