Macrostrat MCP Server

Instructions

Implementation Reference

• src/index.ts:976-999 (registration)

  Registration of the MCP tool named 'defs' which provides access to Macrostrat definitions endpoints
  server.registerTool( "defs", { title: "Definitions", description: "Routes giving access to standard fields and dictionaries used in Macrostrat", inputSchema: { endpoint: z.enum(["lithologies", "structures", "columns", "econs", "minerals", "timescales", "environments", "strat_names", "measurements", "intervals"]).describe("The endpoint to query"), parameters: z.string().describe("parameters to pass to the endpoint"), } }, async (request) => { const { endpoint, parameters } = request; const params = new URLSearchParams(parameters); const response = await fetch(`${getApiEndpoint("base")}/defs/${endpoint}?${params}`); const data = await response.json(); return { content: [{ type: "text" as const, text: JSON.stringify(data, null, 2) }] }; } );
• src/index.ts:986-998 (handler)

  Handler function that extracts endpoint and parameters, constructs query to Macrostrat API /defs/{endpoint}, fetches JSON response, and returns formatted text content
  async (request) => { const { endpoint, parameters } = request; const params = new URLSearchParams(parameters); const response = await fetch(`${getApiEndpoint("base")}/defs/${endpoint}?${params}`); const data = await response.json(); return { content: [{ type: "text" as const, text: JSON.stringify(data, null, 2) }] }; }
• src/index.ts:978-985 (schema)

  Tool metadata including title, description, and Zod input schema defining 'endpoint' enum and 'parameters' string
  { title: "Definitions", description: "Routes giving access to standard fields and dictionaries used in Macrostrat", inputSchema: { endpoint: z.enum(["lithologies", "structures", "columns", "econs", "minerals", "timescales", "environments", "strat_names", "measurements", "intervals"]).describe("The endpoint to query"), parameters: z.string().describe("parameters to pass to the endpoint"), } },
• src/index.ts:648-670 (helper)

  Helper function getApiEndpoint used by defs handler to resolve base API URL for defs endpoints
  function getApiEndpoint(type: "mapUnits" | "units" | "columns" | "base"): string { const endpoint = ROOTS.find((root) => { if (root.type !== "api") return false; switch (type) { case "mapUnits": return root.uri === "https://macrostrat.org/api/geologic_units/map"; case "units": return root.uri === "https://macrostrat.org/api/units"; case "columns": return root.uri === "https://macrostrat.org/api/columns"; case "base": return root.uri === "https://macrostrat.org/api"; default: return false; } }); if (!endpoint) { throw new Error(`API endpoint not found for type: ${type}`); } return endpoint.uri; }