Awels MCP Server - PDF Processing Tool

A Model Context Protocol (MCP) server that provides PDF processing capabilities using docling. This server exposes a single tool to convert PDF files to Markdown format with optional image extraction, designed to run in isolated environments to avoid permission issues.

Project Structure

awels-mcp/
├── src/
│   └── awels_mcp/
│       ├── pdf_processor/     # PDF processing functionality
│       │   └── __init__.py    # PDFProcessor implementation
│       ├── __init__.py        # Package initialization
│       ├── run_server.py      # Server entry point
│       └── server.py          # MCP server implementation
├── tests/                     # Test files
│   ├── artifacts/             # Test artifacts (PDFs, outputs)
│   │   ├── test_output_md/    # Generated markdown files
│   │   ├── test_output_images/# Extracted images
│   │   └── test_pdfs/         # Sample PDFs for testing
│   ├── test_client.py         # Test MCP client
│   ├── test_pdf_processor.py  # Unit tests for PDF processing
│   └── test_server.py         # Server tests
├── .gitignore
├── INSTALL.md                 # Installation instructions
├── LICENSE
├── PLAN.md
├── README.md                  # This file
├── pyproject.toml             # Project metadata and dependencies
└── requirements.txt           # Development dependencies

Features

• PDF to Markdown Conversion: Convert PDF files to clean Markdown format using docling

• Image Extraction: Extract images from PDFs (page images, tables, figures)

• Batch Processing: Process multiple PDF files in a directory (with recursive search)

• Structured Output: Returns detailed JSON results with file metadata and processing statistics

• Isolated Execution: Designed to run with uvx --isolated to prevent permission issues

• Error Handling: Graceful handling of permission errors and processing failures

Installation

See INSTALL.md for detailed installation instructions using uv.

Quick Start

1. Install the package in development mode:

uv venv
source .venv/bin/activate  # On Windows: .venv\Scripts\activate
uv pip install -e .

2. Run the tests to verify the installation:

pytest tests/

3. Start the MCP server:

python -m src.awels_mcp.run_server

4. In a separate terminal, run the test client:

python tests/test_client.py

Running Tests

The test suite includes:

• Unit tests for the PDF processor

• Integration tests for the MCP server

• End-to-end tests with the client

To run all tests:

pytest tests/

Test artifacts (generated markdown and images) are saved in the tests/artifacts/ directory.

Development

Project Structure

• src/awels_mcp/: Main package source code

  • pdf_processor/: PDF processing functionality

  • server.py: MCP server implementation

  • run_server.py: Entry point for the MCP server

Adding New Features

1. Create a new branch for your feature

2. Add tests for your feature in the appropriate test file

3. Implement your feature

4. Run tests to ensure everything works

5. Submit a pull request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Integration with MCP Clients

Add to your MCP client configuration (e.g., Claude Desktop):

{
  "mcpServers": {
    "awels-pdf-processor": {
      "command": "uvx",
      "args": [
        "--python=3.12",
        "--isolated", 
        "--from=git+https://github.com/your-org/awels-mcp.git",
        "awels-mcp-server"
      ]
    }
  }
}

Tool Reference

convert_pdf

Converts PDF files in a directory to Markdown with optional image extraction.

Parameters:

• directory (string, required): Directory path to search for PDF files

• recursive (boolean, optional): Whether to search recursively in subdirectories (default: true)

• markdown_output_path (string, optional): Directory to save markdown files

• images_dir (string, optional): Directory to extract images from PDFs

Returns: Structured JSON with processing results:

{
  "summary": {
    "total_files": 5,
    "successful": 4,
    "failed": 1,
    "total_pages": 120,
    "total_images_extracted": 25
  },
  "files": {
    "/path/to/file1.pdf": {
      "filename": "file1.pdf",
      "name": "file1.pdf",
      "size": 1024000,
      "modified": 1640995200.0,
      "pages": 10,
      "metadata": {
        "title": "Document Title",
        "author": "Author Name",
        "subject": "Document Subject"
      },
      "extracted_images": [
        "/path/to/images/file1-page-1.png",
        "/path/to/images/file1-table-1.png"
      ],
      "markdown_file": "/path/to/markdown/file1.md",
      "content": "# Document Title\n\nDocument content in markdown..."
    },
    "/path/to/file2.pdf": {
      "error": "Failed to convert PDF: Permission denied"
    }
  }
}

Usage Examples

Basic PDF Conversion

# Convert all PDFs in a directory to markdown (content returned in response)
convert_pdf(directory="/path/to/pdfs")

Save Markdown Files

# Convert PDFs and save markdown files to disk
convert_pdf(
  directory="/path/to/pdfs",
  markdown_output_path="/path/to/output/markdown"
)

Extract Images

# Convert PDFs and extract all images
convert_pdf(
  directory="/path/to/pdfs",
  markdown_output_path="/path/to/output/markdown",
  images_dir="/path/to/output/images"
)

Non-Recursive Search

# Only process PDFs in the specified directory (no subdirectories)
convert_pdf(
  directory="/path/to/pdfs",
  recursive=false
)

Architecture

The server uses:

• FastMCP: High-level MCP server framework for easy tool definition

• docling: Advanced PDF processing library for text and image extraction

• Pydantic: Data validation and structured output

• Isolated execution: Runs in isolated environment to prevent permission issues

Error Handling

The server gracefully handles:

• Permission errors (designed to run in isolated environments)

• Missing directories

• Corrupted PDF files

• Processing failures

• File system errors

All errors are reported in the structured output with detailed error messages.

Development

Project Structure

awels/
├── src/
│   └── awels_mcp/
│       ├── __init__.py
│       ├── server.py          # Main MCP server implementation
│       └── pdf_processor.py   # PDF processing logic
├── pyproject.toml             # Package configuration
├── README.md                  # This file
└── PLAN.md                    # Development plan

Running Tests

# Install development dependencies
uv sync --group dev

# Run tests (when available)
uv run pytest

Code Formatting

# Format code
uv run black src/
uv run isort src/

# Type checking
uv run mypy src/

Requirements

• Python 3.10+

• docling and docling-core libraries

• MCP Python SDK

• Sufficient disk space for temporary files and model downloads

License

MIT License - see LICENSE file for details.

Contributing

1. Fork the repository

2. Create a feature branch

3. Make your changes

4. Add tests if applicable

5. Submit a pull request

Support

For issues and questions:

• GitHub Issues: https://github.com/your-org/awels-mcp/issues

• Documentation: See PLAN.md for technical details