Local-first file conversion MCP server supporting image, video, audio, document, data, and ebook formats
ConvX defines 10 tools with complete JSON schemas and descriptions. However, critical gaps limit production readiness: (1) Tool names lack action verbs, 'usage-guide', 'convert_file', 'get_supported_formats' mix styles; (2) Descriptions are present but generic (avg ~100 chars, below 194-char baseline); (3) Parameter descriptions exist but lack format/constraint details (e.g., 'quality' has no range hint, 'output_format' no enum); (4) No output schemas documented, LLMs cannot predict response structure; (5) Error handling is minimal, no recovery guidance or categorization. The server is functional but does not meet production-grade tool patterns for LLM reasoning.
Convert multiple files to a target format with shared options
Check if conversion from one format to another is supported
Check if all required external dependencies (ffmpeg, LibreOffice, etc.) are installed and accessible
Convert a single file from one format to another with optional quality, size, and dimension parameters
Get list of formats that a source format can be converted to
Get metadata about a file including format detection and conversion recommendations
Get detailed configuration for a specific preset
No output schemas documented. LLMs cannot predict response structure, forcing them to guess what fields are returned and how to chain tools. E.g., convert_file returns what? A file path? Metadata? Base64 content?
Parameter descriptions lack format/constraint details. 'quality' (0-100) has no range hint; 'output_format' has no enum of valid formats; 'width' and 'fps' have no bounds. LLMs will pass invalid values.
Tool 'usage-guide' has no action verb and is not a standard MCP pattern. It appears to be documentation rather than a callable tool. Consider removing or renaming to 'get_usage_guide'.
Error handling is minimal. No recovery guidance (e.g., 'If conversion fails, check_dependencies first'). No error categorization (retryable vs. fatal). LLMs cannot plan recovery.
Inferred effective spec: 2025-06-18+.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-23 | C | 66 | 2025-06-18+ | v2 |
List all supported file formats across categories (image, video, audio, document, data, ebook)
List all available conversion presets with their configurations
Important guidelines for using ConvX MCP tools effectively
Mutually exclusive parameters not documented. 'convert_file' accepts both 'input_path' and 'input_content'; 'batch_convert' accepts both 'input_paths' and 'input_contents'. Descriptions should state 'Provide exactly one of input_path or input_content'.