MeSH MCP

Instructions

Implementation Reference

• src/mesh_mcp/server.py:103-147 (handler)

  The search_mesh tool is defined as an MCP tool, querying the NLM descriptor lookup endpoint and formatting the results into a list of descriptors with labels, UI IDs, and URIs.

  @mcp.tool()
  def search_mesh(query: str, match: str = "startsWith", limit: int = 10) -> dict:
      """
      Search MeSH descriptors by label using the NLM Lookup autocomplete endpoint.
  
      Use this to find the MeSH UI code and URI for a biomedical concept before
      calling get_mesh_record or get_mesh_qualifiers.
  
      Parameters
      ----------
      query : str
          The label string to search for (e.g. "diabetes", "neoplasms").
      match : str
          Matching strategy:
            "startsWith" — left-anchored (default, analogous to LCSH suggest2)
            "contains"   — substring match anywhere in the label
            "exact"      — exact match only
      limit : int
          Maximum number of results to return (default 10, max 50).
  
      Returns
      -------
      dict
          A 'results' list of {label, ui, uri} dicts, or an 'error' key.
          'ui'  is the MeSH unique identifier (e.g. "D003920").
          'uri' is the full RDF URI (e.g. "http://id.nlm.nih.gov/mesh/D003920").
      """
      result = _get(
          f"{_LOOKUP_BASE}/descriptor",
          params={"label": query, "match": match, "limit": min(limit, 50)},
      )
      if "error" in result:
          return result
  
      raw = result["data"]
      if not isinstance(raw, list):
          return {"error": "Unexpected response format from NLM lookup", "data": raw}
  
      results = []
      for item in raw:
          uri   = item.get("resource", "")
          label = item.get("label", "")
          ui    = _uri_to_id(uri) if uri else ""
          results.append({"label": label, "ui": ui, "uri": uri})
      return {"results": results}