opensolr-mcp

MCP (Model Context Protocol) server for Opensolr — gives any AI agent managed Apache Solr search as tools: hybrid (BM25 + kNN) retrieval, server-side GPU embeddings, document indexing, and grounded RAG answers.

No embedding model to configure. No vector database to run. One API key.

Tools

Setup

Get a free Opensolr account (15-day trial, no card) at opensolr.com/register and copy your API key from Account.

Claude Desktop / Claude Code

{
  "mcpServers": {
    "opensolr": {
      "command": "uvx",
      "args": ["opensolr-mcp"],
      "env": {
        "OPENSOLR_EMAIL": "you@example.com",
        "OPENSOLR_API_KEY": "YOUR_OPENSOLR_API_KEY"
      }
    }
  }
}

Cursor / Windsurf / any MCP client

Same shape — stdio transport, command uvx opensolr-mcp (or pipx run opensolr-mcp), with OPENSOLR_EMAIL and OPENSOLR_API_KEY in env.

Example agent session

You: Index our FAQ answers, then find everything about refunds.

The agent calls opensolr_add_documents(index="faq__dense", texts=[...]), then opensolr_search(index="faq__dense", query="refund policy", hybrid=True) — BM25 catches the exact word "refund", kNN catches "giving customers their money back", and the scores fuse per document.

Notes

• Vector-enabled indexes run on Opensolr's Solr 9.x environments — currently us (Chicago), de (Germany), fi (Finland), fetched live via opensolr_vector_regions. Additional dedicated regions can be deployed on request (paid add-on): support@opensolr.com.
• Every index is also plain Apache Solr with the native /select API — nothing is locked behind the tools.
• Python sibling for LangChain: langchain-opensolr · Product page: opensolr.com/langchain

MIT license.