mdx-mcp

An open-source, verified natural-language → MDX MCP server for OLAP cubes.

Ask an OLAP/SSAS multidimensional cube questions in plain English and get back a verified answer — the number, the MDX that produced it, and an honest abstain/clarify when the query is ambiguous. Cross-platform (XMLA), provider-agnostic (Claude by default), and MCP-native.

question ──▶ introspect the cube ──▶ generate k candidate MDX ──▶ execute (read-only)
         ──▶ self-consistency verify ──▶ { status, value, mdx, agreement }

Why it's different

• Verified, not vibes. It runs k diverse candidate queries and only answers when they agree; on divergence it abstains or asks to clarify instead of guessing a number.
• Works on any cube. Cube-schema introspection auto-grounds generation — no per-cube hand-authoring.
• Read-only by construction. Only SELECT/WITH MDX ever executes.
• Open-core. Three clean seams (LLMClient, MdxExecutor, Verifier) let you plug in a private trust layer without forking. See ARCHITECTURE.md.

Install

pip install mdx-mcp[claude]     # engine + Claude reference provider

The XMLA executor and cube introspection use only the Python standard library.

Configure (env)

export MDX_MCP_ENDPOINT="http://your-ssas-host/olap/msmdpump.dll"   # XMLA endpoint
export MDX_MCP_CATALOG="YourDatabase"
export MDX_MCP_CUBE="Your Cube"
export MDX_MCP_USER="user"           # optional (basic auth)
export MDX_MCP_PASSWORD_FILE="/run/secrets/olap_pw"   # or MDX_MCP_PASSWORD
export ANTHROPIC_API_KEY="sk-..."    # for the default Claude producer

Run

mdx-mcp        # starts the MCP server (stdio)

Tools

Tool	Purpose
mdx_introspect	the cube's grounding block (measures / dimensions / hierarchies)
mdx_ask	NL question → { status: answer|abstain|clarify, value, mdx, agreement }
mdx_run	execute a provided MDX query (read-only)
mdx_explain	explain an MDX query in plain language

Ships a Cube-Analyst persona (persona/) and Claude skills (skills/) that drive the flow.

Bring your own provider / backend

Implement LLMClient (any model), MdxExecutor (e.g. a Windows ADOMD backend), or Verifier (e.g. a calibrated trust gate) and inject it — the engine is unchanged.

License

Apache-2.0. No vendor lock-in, no client data.