BACH FileCommander

ellmos FileCommander MCP Server

🇩🇪 Deutsche Version

Part of the ellmos-ai family.

Quick Navigation: Tools Overview | System Architecture | Core Capabilities & Safety Invariants | Installation | Configuration | Comparison | Discoverability | Security | Ecosystem | Security Policy | Changelog | llms.txt

A comprehensive Model Context Protocol (MCP) server that gives AI assistants full filesystem access, bounded multi-file content search, process management, interactive shell sessions, and async filename search capabilities.

50 tools in a single server - everything an AI agent needs to interact with the local system.

Discovery keywords: local filesystem MCP server, multi-file content search MCP, safe delete MCP, Recycle Bin MCP server, process management MCP, interactive shell MCP, async file search for AI agents, cloud-lock-safe file operations, Markdown to PDF MCP, OCR MCP server, ZIP archive MCP.

Registry status: published on npm, indexed by jsDelivr, visible on LobeHub, listed on Glama, and prepared for the official MCP Registry via server.json. Some third-party directories still show older 43-tool metadata, so the canonical README/npm metadata should remain the source of truth until their reindex catches up.

[!NOTE] For AI Agents & LLM Integrations: FileCommander provides 50 specialized tools accessible via standard stdio transport. All tool names use the fc_ prefix to prevent namespace collisions. For LLMs, compact context and schema overviews are available in llms.txt and server.json.

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Why FileCommander?

Most filesystem MCP servers only cover basic read/write operations. FileCommander goes further:

• Safe Delete - Moves files to Recycle Bin (Windows) or Trash (macOS/Linux) instead of permanent deletion
• Interactive Sessions - Start and interact with REPLs (Python, Node.js, shells) through the MCP protocol
• Async Search - Search large directory trees in the background while the AI continues working
• Explicit Content Search - Search literal text or regex across a bounded list of files without recursion or glob expansion
• Process Management - List, start, and terminate system processes
• String Replace - Edit files by matching unique strings with context validation
• Format Conversion - Convert between JSON, CSV, INI, YAML, TOML, XML, and TOON
• ZIP Archives - Create, extract, and list ZIP archives
• File Checksums - MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashing with compare
• OCR - Extract text from images (optional tesseract.js dependency)
• Safety Mode - Toggle to route all deletes through Recycle Bin / Trash
• Markdown Export - Convert Markdown to professional HTML/PDF with code blocks, tables, nested lists, blockquotes
• Cloud-Lock Safe - Automatic copy+delete fallback when cloud sync filters (OneDrive, Dropbox, Google Drive, iCloud) block rename operations
• Cloud Lock Diagnosis - Check whether a path is at risk of sync-filter conflicts before operating
• Cross-platform - Works on Windows, macOS, and Linux with platform-specific optimizations

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System Architecture

flowchart TD
    subgraph Client["MCP Client Layer"]
        Claude["Claude Desktop / Claude Code"]
        Custom["Custom LLM Agents / Frameworks"]
    end

    subgraph Transport["Transport Layer"]
        Stdio["Stdio Transport (JSON-RPC)"]
    end

    subgraph Core["ellmos FileCommander Engine (50 Tools)"]
        FS["Filesystem Engine\n(15 tools: read, bounded preview, write, edit, safe-delete, cloud-lock safe)"]
        Search["Search Engine\n(6 tools: explicit content search plus 5 async filename-search tools)"]
        Proc["Process & REPL Sessions\n(10 tools: exec, default-app opening, background proc, interactive REPLs)"]
        Repair["Repair & Format Converter\n(9 tools: JSON fix, Mojibake fix, duplicates, format convert, checksum)"]
        Export["Export & Web Fetch\n(3 tools: Markdown->HTML/PDF, web_fetch)"]
        Sys["System, Utilities & i18n\n(7 tools: OCR, ZIP, cloud-lock check, safe-mode, time, language set/get)"]
    end

    Client -->|JSON-RPC| Stdio
    Stdio --> Core
    Core --> FS
    Core --> Search
    Core --> Proc
    Core --> Repair
    Core --> Export
    Core --> Sys

sequenceDiagram
    autonumber
    participant AI as AI Assistant (Client)
    participant FC as FileCommander Engine
    participant FS as Host Filesystem
    participant Trash as Recycle Bin / Trash
    participant Cloud as Cloud Sync Filter

    Note over AI,FC: 1. Safe Deletion & Recovery Protection
    AI->>FC: fc_delete_file / fc_safe_delete(targetPath)
    alt Safety Mode Active or fc_safe_delete invoked
        FC->>Trash: Move item to Recycle Bin / Trash
        Trash-->>FC: Moved safely (recoverable)
        FC-->>AI: Success (item preserved in Trash/Recycle Bin)
    else Permanent Unlink requested
        FC->>FS: Direct unlink
        FS-->>FC: Removed permanently
        FC-->>AI: Success
    end

    Note over AI,Cloud: 2. Resilient Cloud-Lock Handling (OneDrive/Dropbox)
    AI->>FC: fc_move(sourcePath, destPath)
    alt Cloud Filter Locks Destination
        FC->>Cloud: Attempt standard rename
        Cloud-->>FC: EPERM / EBUSY (Cloud Filter Error)
        FC->>FS: Fallback: copyFileSync + SHA-256 verify
        FC->>FS: unlinkSync source
        FC-->>AI: Move succeeded via resilient fallback
    else Local Native Filesystem
        FC->>FS: Rename (atomic)
        FS-->>FC: Done
        FC-->>AI: Move succeeded
    end

---

Core Capabilities & Safety Invariants

Capability / Invariant	Guarantee & Implementation Details	Security & Operational Benefit
Local stdio & explicit egress	The MCP transport is local stdio, with no telemetry and no automatic network egress. fc_web_fetch makes outbound HTTP(S) requests only when a client explicitly invokes it; private targets are blocked by default unless allow_private is enabled.	Makes the network boundary visible to clients while retaining a local, port-free server transport.
Safe Deletion & Trash Protection	fc_safe_delete moves items to Windows Recycle Bin / macOS Trash / Linux FreeDesktop Trash. fc_set_safe_mode routes all deletes safely.	Prevents irreversible data loss from accidental recursive or bulk deletions.
Cloud-Lock Resilient Move (fc_move)	Automatic detection of cloud sync filters (OneDrive, Dropbox, iCloud reparse points) with seamless copy+verify+delete fallback.	Eliminates EPERM / EBUSY failures during automated agent operations in sync directories.
Cloud-Lock Diagnosis (fc_check_cloud_lock)	Pre-flight inspection for offline sync attributes, reparse points, and placeholder file states.	AI agents can avoid operating on un-hydrated or locked cloud files before execution.
Bounded Multi-File Content Search	fc_search_content strictly caps inputs (max 50 explicit files, 10 MB per file, 200 matches, 200k chars) without glob recursion.	Prevents out-of-memory errors and catastrophic CPU lockups during large repository searches.
Automated Secret & Token Redaction	Content search excerpts automatically mask common API keys, bearer tokens, AWS credentials, and authorization headers.	Prevents LLM context contamination and accidental credential leakage in prompt history.
Interactive REPL & Session Isolation	Stateful interactive sessions (fc_start_session, fc_send_input, fc_read_output) for Python, Node.js, bash, and PowerShell with bounded buffers.	Allows multi-turn REPL debugging without unconstrained background process buildup.
Lossless Multi-Format Engine	Declarative conversion (fc_convert_format) across 7 structured formats (JSON, YAML, TOML, XML, CSV, INI, TOON).	Clean data normalization across heterogeneous configuration formats without data loss.
Mojibake & File Repair Engine	fc_fix_encoding, fc_fix_json, and fc_cleanup_file repair broken UTF-8 encoding (27+ patterns), malformed JSON syntax, BOMs, and NUL bytes.	Self-healing pipelines for corrupted files generated across divergent OS platforms.
Unprivileged Non-Elevation Execution	Designed and verified to run in standard unprivileged user-mode. Never requires administrative or root privileges.	Minimal attack surface; adheres to the principle of least privilege.
Six-language Runtime i18n Engine	Dynamic language switching and introspection (fc_set_language, fc_get_language) for German (de), English (en), Spanish (es), Chinese (zh), Japanese (ja), and Russian (ru).	Native multilingual developer experience and localized error reporting.
Multi-OS Verified Matrix	Tested across Windows, Ubuntu Linux, and macOS on Node.js 20, 22, and 24 with 283 automated assertions.	Continuous cross-platform parity and reliability.

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Installation

Prerequisites

• Node.js 20 or higher
• npm

Option 1: Install from NPM

npm install -g ellmos-filecommander-mcp

Option 2: Install from Source

git clone https://github.com/ellmos-ai/ellmos-filecommander-mcp.git
cd ellmos-filecommander-mcp
npm install
npm run build

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Configuration

Claude Desktop

Add to your claude_desktop_config.json:

Windows: %APPDATA%\Claude\claude_desktop_config.json macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

If installed globally via NPM:

{
  "mcpServers": {
    "filecommander": {
      "command": "ellmos-filecommander"
    }
  }
}

If installed from source:

{
  "mcpServers": {
    "filecommander": {
      "command": "node",
      "args": ["/absolute/path/to/filecommander-mcp/dist/index.js"]
    }
  }
}

Restart Claude Desktop after saving.

Other MCP Clients

The server communicates via stdio transport. Point your MCP client to the dist/index.js entry point or the ellmos-filecommander binary.

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Tools Overview

Filesystem Operations (15 tools)

Tool	Description
fc_read_file	Read file contents with optional line limit
fc_preview_file	Inspect MIME type and size first, then explicitly request bounded inline MCP content
fc_read_multiple_files	Read up to 20 files in a single call
fc_write_file	Write/create/append to files
fc_edit_file	Line-based editing (replace, insert, delete lines)
fc_str_replace	Replace a unique string in a file with context validation
fc_list_directory	List directory contents (recursive, configurable depth)
fc_create_directory	Create directories (including parents)
fc_delete_file	Delete a file (permanent)
fc_delete_directory	Delete a directory (with optional recursive flag)
fc_safe_delete	Move to Recycle Bin / Trash (recoverable!)
fc_move	Move or rename files and directories (cloud-lock safe)
fc_copy	Copy files and directories
fc_file_info	Get detailed file metadata (size, dates, type)
fc_search_files	Synchronous file search with wildcard patterns

fc_preview_file is the remote/headless fallback for local files. Its default call returns structured metadata only: resolved path, file:// URI, MIME type, byte size, preview kind, fixed 1 MiB limit, and the exact follow-up call. Content is read only after include_content=true. Eligible text and raster images use standard MCP text/image content blocks; PDFs use a bounded embedded resource. Files above 1 MiB and unsupported types remain metadata-only and are never read or Base64-encoded by the preview path.

Content Search (1 tool)

Tool	Description
fc_search_content	Read-only literal or regex search within an explicit ordered list of files, with case, context, global, and per-file limits

fc_search_content never expands globs, traverses directories, or recursively discovers files. It accepts at most 50 explicit UTF-8 text files, skips binary and files over 10 MB, and returns deterministic JSON. Matches are limited to 200 globally and 100 per file, context to 10 lines, excerpts to 500 characters, and serialized output to 200,000 characters. Missing, cloud-only, permission, encoding, binary, and size failures are reported per file so readable files still produce results. Common secret formats are redacted from excerpts.

Async Search (5 tools)

Tool	Description
fc_start_search	Start a background search (returns immediately)
fc_get_search_results	Retrieve results with pagination
fc_stop_search	Cancel a running search
fc_list_searches	List all active/completed searches
fc_clear_search	Remove completed searches from memory

Process Management (5 tools)

Tool	Description
fc_execute_command	Execute a shell command (blocking, with timeout)
fc_start_process	Start a background process (non-blocking)
fc_open_path	Validate and open an existing local file or directory with the OS default application
fc_list_processes	List running system processes
fc_kill_process	Terminate a process by PID or name

fc_open_path accepts only an existing file or directory and sends it to a fixed native default-handler launcher. Its structured result reports launcher_accepted=true|false, always reports user_visible="unknown", and identifies a machine-readable fallback: fc_preview_file with metadata-only arguments for files or fc_list_directory for directories. Launcher acceptance never claims that a GUI became visible. fc_start_process instead lets the caller choose an executable and arguments. fc_execute_command accepts an arbitrary shell command: Node's default shell is used for ordinary commands (COMSPEC/cmd.exe on Windows), while FileCommander's Windows special-character path can route through Windows PowerShell.

Interactive Sessions (5 tools)

Tool	Description
fc_start_session	Start an interactive process (Python, Node, shell...)
fc_read_output	Read session output
fc_send_input	Send input to a running session
fc_list_sessions	List all sessions
fc_close_session	Terminate a session

File Maintenance & Repair (9 tools)

Tool	Description
fc_fix_json	Repair broken JSON (BOM, trailing commas, comments, single quotes)
fc_validate_json	Validate JSON with detailed error position and context
fc_cleanup_file	Remove BOM, NUL bytes, trailing whitespace, normalize line endings
fc_fix_encoding	Fix Mojibake / double-encoded UTF-8 (27+ character patterns)
fc_folder_diff	Track directory changes with snapshots (new/modified/deleted)
fc_batch_rename	Pattern-based batch renaming (prefix/suffix, replace, auto-detect)
fc_convert_format	Convert between JSON, CSV, INI, YAML, TOML, XML, and TOON formats
fc_detect_duplicates	Find duplicate files using SHA-256 hashing
fc_checksum	File hashing (MD5, SHA-1, SHA-256, SHA-384, SHA-512) with optional compare

Archive (1 tool)

Tool	Description
fc_archive	Create, extract, and list ZIP archives

OCR (1 tool)

Tool	Description
fc_ocr	Extract text from images via tesseract.js (optional dependency)

Cloud Sync (1 tool)

Tool	Description
fc_check_cloud_lock	Diagnose whether a path may be blocked by cloud sync filters (Windows)

System (4 tools)

Tool	Description
fc_get_time	Get current system time with timezone info
fc_set_safe_mode	Toggle safe mode: all deletes go through Recycle Bin / Trash
fc_set_language	Set the runtime language (de, en, es, zh, ja, or ru)
fc_get_language	Read the active runtime language and all supported language codes

Export (2 tools)

Tool	Description
fc_md_to_html	Markdown to standalone HTML with CSS styling (headers, code blocks, tables, nested lists, blockquotes, images, checkboxes)
fc_md_to_pdf	Markdown to PDF via headless browser (Edge/Chrome). Falls back to HTML if no browser is available

Web (1 tool)

Tool	Description
fc_web_fetch	Fetch a web page and return content by mode: extract (clean main text), raw (HTTP body), links, forms, or headers. Read-only network tool; SSRF guard blocks internal/private targets by default.

Total: 50 tools

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Comparison with Alternatives

Feature	FileCommander	Desktop Commander	Official Filesystem
File read/write/copy/move	14 tools	Yes	Yes
Safe delete (Recycle Bin)	Yes	No	No
Explicit multi-file content search	Yes	No	No
Async background search	5 tools	No	No
Interactive sessions (REPL)	5 tools	Yes	No
Process management	5 tools	Yes	No
Shell command execution	Yes	Yes	No
String replace with validation	Yes	Yes	No
Line-based file editing	Yes	No	No
JSON repair & validation	2 tools	No	No
Encoding fix (Mojibake)	Yes	No	No
Duplicate detection (SHA-256)	Yes	No	No
Folder diff / change tracking	Yes	No	No
Batch rename (pattern-based)	Yes	No	No
Format conversion (JSON/CSV/INI/YAML/TOML/XML/TOON)	Yes	No	No
ZIP archive (create/extract/list)	Yes	No	No
File checksums (MD5/SHA-1/SHA-256/SHA-384/SHA-512)	Yes	No	No
OCR (image to text)	Optional	No	No
Safety mode (delete → Recycle Bin)	Yes	No	No
Path allowlist / sandboxing	No	No	Yes
Excel / PDF support	PDF (via browser)	Yes	No
HTTP transport	No	No	No
Markdown to HTML/PDF export	Yes	No	No
Total tools	50	~15	~11
Servers needed	1	1	+ extra for processes

Key differentiators:

• Only MCP server with recoverable delete (Recycle Bin / Trash)
• Only MCP server with async background search with pagination
• Built-in JSON repair, encoding fix, and duplicate detection
• Only MCP server with cloud-lock-safe file operations (automatic copy+delete fallback)
• Most comprehensive single-server solution (50 tools)
• Built-in safety mode to prevent accidental permanent deletion

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Tool Prefix

All tools use the fc_ prefix (FileCommander) to avoid conflicts with other MCP servers.

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Discoverability

FileCommander is designed to be discoverable by both people and AI agents:

• package.json exposes the official mcpName (io.github.ellmos-ai/ellmos-filecommander-mcp) and MCP-specific npm keywords.
• server.json follows the official MCP Registry schema and points to the npm package.
• glama.json provides MCP-directory metadata for Glama-compatible indexes.
• llms.txt gives compact context for LLMs, agent catalogs, and documentation crawlers.

Primary search terms: ellmos-filecommander-mcp, FileCommander MCP, filesystem MCP server, multi-file content search MCP, safe delete MCP, async file search MCP, process management MCP, Markdown PDF MCP.

External discovery notes: npm and jsDelivr may briefly lag behind the current release. LobeHub indexes the GitHub repo as an MCP server. Use the package description and this README as the canonical 50-tool source for the current repository.

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Security

This server has full filesystem access with the running user's permissions.

See SECURITY.md for detailed security information and recommendations.

Key points:

• fc_execute_command runs arbitrary shell commands
• fc_open_path invokes the operating system's associated application for a caller-selected existing path; that application runs with the user's permissions
• fc_open_path reports launcher acceptance separately from the invariant user_visible="unknown"; fc_preview_file is the metadata-first remote fallback with an explicit 1 MiB inline-content boundary
• fc_start_session starts an arbitrary interactive command, and subsequent fc_send_input calls can execute additional actions
• fc_delete_* tools perform permanent deletion by default (use fc_safe_delete or enable safe mode via fc_set_safe_mode to route all deletes through Recycle Bin / Trash)
• Safe mode protects only fc_delete_file and fc_delete_directory; it does not sandbox commands or interactive sessions
• The server transport is local stdio and emits no telemetry, but an explicit fc_web_fetch call performs outbound HTTP(S) access
• No built-in sandboxing - security is delegated to the MCP client layer

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Development

# Install dependencies
npm install

# Watch mode (auto-rebuild on changes)
npm run dev

# One-time build
npm run build

# Start the server
npm start

# Run test suite
npm test

Testing

The project includes 212 Vitest tests plus 71 standalone i18n checks (283 total) covering filesystem operations, metadata-first inline preview, bounded content search, native default-handler launching, format conversion, encoding repair, archive handling, duplicate detection, language packs, tool annotations, real stdio behavior, and security boundaries.

npm test              # Run all tests
node test-i18n.mjs    # Run standalone i18n checks
npx vitest run        # Same as above
npx vitest --watch    # Watch mode

Tests are verified on Windows, macOS, and Linux. Pushes and pull requests run CI on Node.js 20, 22, and 24 with npm ci, TypeScript build, Vitest, and an npm package dry-run.

See CONTRIBUTING.md for contribution guidelines.

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Changelog

See CHANGELOG.md for the full version history.

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License

MIT - Lukas Geiger (ellmos-ai)

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History

This project was originally developed as BACH FileCommander (bach-filecommander-mcp). It has been renamed to ellmos FileCommander (ellmos-filecommander-mcp) as part of the ellmos-ai organization.

The legacy package name bach-filecommander-mcp is deprecated. Please use ellmos-filecommander-mcp instead:

npm uninstall -g bach-filecommander-mcp
npm install -g ellmos-filecommander-mcp

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ellmos-ai Ecosystem

This MCP server is part of the ellmos-ai ecosystem — AI infrastructure, MCP servers, and intelligent tools.

MCP Server Family

Server	Tools	Focus	npm
FileCommander	50	Filesystem, bounded inline preview, content search, default-app opening, process management, interactive sessions, cloud-lock-safe operations	ellmos-filecommander-mcp
CodeCommander	22	Code analysis, JSON repair, imports, diffs, regex	ellmos-codecommander-mcp
Clatcher	12	File repair, format conversion, batch operations	ellmos-clatcher-mcp
n8n Manager	19	n8n workflow management via AI assistants	n8n-manager-mcp
ControlCenter	31	MCP stack discovery, profile management, control plane	ellmos-controlcenter-mcp
Homebase	45	Local-first LLM memory, knowledge, state, routing, swarm orchestration	ellmos-homebase-mcp (alpha)
ServerCommander	8	Server operations: health checks, log analysis, deploy dry-runs, mail diagnostics	ellmos-servercommander-mcp (alpha)
Blender Use	5	Headless Blender asset QA and FBX reimport verification	ellmos-blender-use-mcp (alpha)
Open Compute	16	Model-agnostic computer use: capture, safety-gated actions, Windows UIA	open-compute-mcp (alpha)

AI Infrastructure

Project	Description
BACH	Local-first text-based OS for LLM agents — 113+ handlers, 550+ tools, SQLite memory
open-compute	Model-agnostic computer-use core powering Open Compute MCP
clutch	Provider-neutral LLM orchestration with auto-routing and budget tracking
rinnsal	Lightweight agent memory, connectors, and automation infrastructure
ellmos-stack	Self-hosted AI research stack (Ollama + n8n + Rinnsal + KnowledgeDigest)
MarbleRun	Autonomous agent chain framework for Claude Code
gardener	Minimalist database-driven LLM OS prototype (4 functions, 1 table)
ellmos-tests	Testing framework for LLM operating systems (7 dimensions)

Desktop Software & Sibling Applications

Our partner organization open-bricks and its line organizations provide AI-native desktop applications and developer utilities:

Application	Category	Organization	Focus
ProFiler	File Management	file-bricks	High-speed dual-pane file manager with AI integration
ExplorerPro	File Exploration	file-bricks	Smart file explorer with semantic filters & preview
WinStorePackager	Packaging	file-bricks	MSIX & Store packaging for Windows desktop applications
SoftwareCenter	App Store	file-bricks	Centralized desktop package management & distribution
SQLiteViewer	Database Tool	file-bricks	Lightweight SQLite exploration & querying
DokuZen	Markdown Suite	doc-bricks	Markdown editor, PDF export & document conversion
MediaBrain	Document / Media	doc-bricks	Audio/video transcription, metadata extraction & cataloging
UniversalInvoiceMail	Document / Mail	doc-bricks	Automated invoice parsing, PDF extraction & mail routing
DevCenter	Developer Suite	dev-bricks	Integrated developer toolbox, code analyzers & generators
CodeBox	Code Editor	dev-bricks	Multi-language code editor with LLM augmentation
safe-start-for-codex	Security & Audit	dev-bricks	Hardened runtime environment & pre-flight checker for Codex
automation-master	Task Automation	dev-bricks	High-reliability background automation runner & scheduler

Haftung / Liability

Dieses Projekt ist eine unentgeltliche Open-Source-Schenkung im Sinne der §§ 516 ff. BGB. Die Haftung des Urhebers ist gemäß § 521 BGB auf Vorsatz und grobe Fahrlässigkeit beschränkt. Ergänzend gilt der Haftungsausschluss der MIT-Lizenz.

Nutzung auf eigenes Risiko. Keine Wartungszusage, keine Verfügbarkeitsgarantie, keine Gewähr für Fehlerfreiheit oder Eignung für einen bestimmten Zweck.

This project is an unpaid open-source donation. Liability is limited to intent and gross negligence (§ 521 German Civil Code). The MIT license disclaimer also applies. Use at your own risk. No warranty, no maintenance guarantee, no fitness-for-purpose assumed.