Cordra

Cordra is a configurable digital object repository system that stores digital objects as JSON documents with associated metadata and optional binary payloads. This Model Context Protocol (MCP) server provides AI assistants with read-only access to explore and understand Cordra repositories. This allows AI systems to quickly understand the data model and schema structure of a Cordra repository and to explore digital objects and their relationships.

Features

• Read-Only Access: All operations are strictly read-only, ensuring safe exploration without risk of data modification or corruption.
• Schema Discovery: Discover and retrieve schema definitions for each type in the repository.
• Individual Object Retrieval: Retrieve specific digital objects by their handle identifier with complete metadata.

MCP Architecture

Tools

• list_types - List all available types in the Cordra repository.

  • Returns a JSON array of type names that are defined in the repository
  • Types are returned in sorted order

• get_type_schema - Retrieve the JSON schema definition for a specific type.

  • type_name - The name of the type (e.g., "Person", "Document", "Project")
  • Returns the full schema definition as JSON

• get_object - Retrieve a digital object by its complete ID/handle.

  • object_id - Complete object ID (e.g., "test/abc123")

• search_objects - Search for digital objects using a query string with pagination support.

  • query - Lucene/Solr compatible search query
  • type - Optional filter by object type
  • limit - Number of results per page (default: 25)
  • page_num - Page number to retrieve, 0-based (default: 0)

• count_objects - Count the total number of objects matching a query.

  • query - Lucene/Solr compatible search query
  • type - Optional filter by object type

• get_design_object - Retrieve the Cordra design object containing repository configuration.

  • Includes type definitions, workflow configurations, and system settings
  • Administrative privileges are typically required to access this object

Query Syntax

CRITICAL: JSON properties MUST be prefixed with /

✅ Correct Examples:

• /title:*report* - Wildcard search in title field
• /author/name:Daniel - Nested property access
• /status:active AND /priority:high - Boolean operators
• Use type parameter instead of including type: in query

❌ Wrong (will fail):

• name:John - Missing / prefix
• author/name:Daniel - Missing leading /
• type:Person - Use the type parameter instead

Operators: * (wildcard), ? (single char), AND, OR, NOT, "phrases"

Configuration

The MCP server can be configured using environment variables:

• CORDRA_BASE_URL - Cordra server URL (default: https://localhost:8443)
• CORDRA_USERNAME - Username for authentication (optional)
• CORDRA_PASSWORD - Password for authentication (optional)
• CORDRA_VERIFY_SSL - SSL certificate verification (default: true)
• CORDRA_TIMEOUT - Request timeout in seconds (default: 30)
• LOGLEVEL - Logging level (default: INFO, options: DEBUG, INFO, WARNING, ERROR, CRITICAL)

Usage

Run the MCP server:

uv run mcp-cordra

Claude Code

You can add this MCP to Claude Code by registering it in the settings of your project or creating a .mcp.json file in your workdir:

Example using the docker build:

{
  "mcpServers": {
    "cordra": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-e",
        "CORDRA_BASE_URL",
        "ghcr.io/dnlbauer/cordra-mcp:latest"
      ],
      "env": {
        "CORDRA_BASE_URL": "https://cordra.example.de"
      }
    }
  }
}

Example using the python package with uvx:

{
  "mcpServers": {
    "cordra": {
      "command": "uvx",
      "args": [
        "cordra-mcp"
      ],
      "env": {
        "CORDRA_BASE_URL": "https://cordra.example.de"
      }
    }
  }
}