If you've ever asked an LLM to "find the LOINC code for procalcitonin" or "list the active ingredients in Janumet," you've probably watched it confidently invent a code that doesn't exist. Medical terminologies are exactly the kind of structured, frequently-updated reference data that language models are bad at memorizing and good at looking up — if you give them the right tool. medical-terminologies-mcp is a Model Context Protocol server that gives any MCP-compatible client (Claude Desktop, Claude Code, Continue, and others) unified access to seven medical terminology systems: ICD-11 (WHO International Classification of Diseases, 11th Revision) LOINC (Logical Observation Identifiers Names and Codes) RxNorm (NIH normalized clinical drug names) MeSH (NLM Medical Subject Headings) ATC (WHO Anatomical Therapeutic Chemical, served via NLM RxClass) CID-10 (Brazilian Portuguese translation of ICD-10, DataSUS V2008 — bundled) SNOMED CT (Systematized Nomenclature of Medicine, optional, license required) Twenty-six…