Oxigraph MCP Server

A Model Context Protocol (MCP) server for Oxigraph, a fast and lightweight RDF triple store with SPARQL support.

Oxigraph is a high-performance in-memory or file-based RDF graph database written in Rust. This MCP server provides a Claude-friendly wrapper for accessing PyOxigraph (the Python bindings for Oxigraph) through the Model Context Protocol.

Quickstart

Installation

uv pip install mcp-server-oxigraph

Minimal Claude Desktop Configuration

Add the following to your Claude Desktop MCP configuration:

"oxigraph": {
  "command": "uv",
  "args": ["run", "mcp-server-oxigraph"],
  "env": {}
}

Setting a Default Database (Optional)

To set a specific default database location, add the OXIGRAPH_DEFAULT_STORE environment variable:

"oxigraph": {
  "command": "uv",
  "args": ["run", "mcp-server-oxigraph"],
  "env": {
    "OXIGRAPH_DEFAULT_STORE": "~/.claude/my_knowledge_graph.oxigraph"
  }
}

Why Use Oxigraph MCP?

Oxigraph MCP is ideal for:

• Quickly building knowledge bases: Store structured information in a queryable graph database
• Prototyping semantic applications: Test data models and queries interactively
• Schema development: Design and test RDF schemas and ontologies
• Local data storage: Maintain persistent data without external services
• SPARQL exploration: Experiment with complex SPARQL queries in an interactive environment

Features

This MCP server provides:

• Direct PyOxigraph access: Clean, stateless wrapper for PyOxigraph functionality
• Multiple store management: Create, open, and manage multiple file-based stores
• Comprehensive RDF support: Work with all core RDF data types and operations
• Full SPARQL implementation: Execute queries and updates with properly structured results
• Rich serialization options: Support for all major RDF formats

About Oxigraph

Oxigraph is an open-source RDF triple store implemented in Rust. Key features include:

• Fast in-memory or file-based storage using RocksDB
• Full SPARQL 1.1 Query and Update support
• Compliance with W3C standards
• Support for various RDF serialization formats
• Extremely low memory footprint compared to other graph databases

This MCP server uses PyOxigraph, the official Python bindings for Oxigraph.

Supported RDF Formats

The Oxigraph MCP server supports the following RDF serialization formats:

Format	File Extension	MIME Type	Supports Named Graphs
Turtle	.ttl	text/turtle	No
N-Triples	.nt	application/n-triples	No
N-Quads	.nq	application/n-quads	Yes
TriG	.trig	application/trig	Yes
RDF/XML	.rdf	application/rdf+xml	No
N3	.n3	text/n3	No

You can retrieve this information programmatically using the oxigraph_get_supported_formats() function.

Default Store Configuration

The server manages two types of default stores:

1. System Default Store: Located at ~/.mcp-server-oxigraph/default.oxigraph
2. User Default Store: Specified by setting the OXIGRAPH_DEFAULT_STORE environment variable

On startup, the server initializes both stores (if configured):

• The system default store is always created
• If a user default store is specified, it's also initialized
• Operations will use the user default store if specified, otherwise the system default

You don't need to explicitly create or open these stores - they're automatically initialized when the server starts. All operations that don't specify a store path will use the appropriate default store.

Basic Usage Examples

Once configured, you can use the Oxigraph MCP tools in Claude to work with RDF data:

1. Add RDF triples to the default store

   oxigraph_create_named_node(iri: "http://example.org/subject")
   oxigraph_create_named_node(iri: "http://example.org/predicate")
   oxigraph_create_literal(value: "Object value")
   oxigraph_create_quad(subject: subject, predicate: predicate, object: object)
   oxigraph_add(quad: quad)
   

2. Query with SPARQL

   oxigraph_query(query: "SELECT * WHERE { ?s ?p ?o } LIMIT 10")
   

3. Import and export RDF data in different formats

   oxigraph_parse(data: "@prefix ex: <http://example.org/> . ex:a ex:b ex:c .", format: "turtle")
   oxigraph_serialize(format: "ntriples")
   oxigraph_get_supported_formats()
   

4. Create custom stores if needed

   oxigraph_create_store(store_path: "/path/to/my/custom.oxigraph")
   oxigraph_query(query: "SELECT * WHERE { ?s ?p ?o }", store_path: "/path/to/my/custom.oxigraph")
   

API Documentation

Store Management Functions

• oxigraph_create_store: Create a new store (in-memory or file-based)
• oxigraph_open_store: Open an existing file-based store
• oxigraph_close_store: Close a store and remove it from the manager
• oxigraph_backup_store: Create a backup of a store
• oxigraph_restore_store: Restore a store from a backup
• oxigraph_optimize_store: Optimize a store for better performance
• oxigraph_list_stores: List all managed stores

Note: Most operations will work with the default store without needing to specify a store_path. For persistent storage, we recommend using the file path as the store_path for clarity.

RDF Data Model Functions

• oxigraph_create_named_node: Create a NamedNode for use in RDF statements
• oxigraph_create_blank_node: Create a BlankNode for use in RDF statements
• oxigraph_create_literal: Create a Literal for use in RDF statements
• oxigraph_create_quad: Create a Quad (triple with optional graph)
• oxigraph_add: Add a quad to the store
• oxigraph_add_many: Add multiple quads to the store
• oxigraph_remove: Remove a quad from the store
• oxigraph_remove_many: Remove multiple quads from the store
• oxigraph_clear: Remove all quads from the store
• oxigraph_quads_for_pattern: Query for quads matching a pattern

SPARQL Functions

• oxigraph_query: Execute a SPARQL query against the store
• oxigraph_update: Execute a SPARQL update against the store
• oxigraph_query_with_options: Execute a SPARQL query with custom options
• oxigraph_run_query: Run a SPARQL query or update against the store

Serialization Functions

• oxigraph_parse: Parse RDF data and add to the store
• oxigraph_serialize: Serialize the store to a string
• oxigraph_import_file: Import RDF data from a file
• oxigraph_export_graph: Export a graph to a file
• oxigraph_get_supported_formats: Get a list of supported RDF formats

License

MIT License