# MCP Bridge for Virtuoso (Community Edition)

A custom MCP server that lets OpenClaw (or any LLM agent) access Virtuoso Community Edition as a semantic backend without running raw SPARQL from the agent. The MCP layer exposes structured tools that orchestrate queries and later aggregate data across additional stores (PostgreSQL, CouchDB, Qdrant).

## Vision

- LLMs never issue SQL/SPARQL directly—they call MCP tools.
- The MCP server handles orchestration, sanitization, rate limiting, and multi-source composition.
- Start with Virtuoso (SPARQL) and progressively add new connectors.

## Architecture

```
LLM Agent (OpenClaw)
↓
MCP Server
├── Virtuoso (SPARQL)
├── PostgreSQL
└── Vector DBs (e.g., Qdrant)
```

## Design Principles

1. Tool-based abstraction: Provide helpers such as `sparql_query`, `get_entities_by_type`, `list_graphs` instead of exposing raw SPARQL.
2. Gradual complexity: Ship a minimal working setup, then layer on helper tooling, schema introspection, and connectors.
3. Separation of concerns: Virtuoso stores RDF, MCP runs tool interfaces, and LLMs focus on reasoning/tool selection.

## Success Criteria

- Phase 1: MCP tool (`sparql_query`) returns valid SPARQL JSON results.
- Phase 2: LLM relies on helper tools instead of free-form queries.
- Phase 3: Multiple data sources accessible through a unified MCP interface.