Medusa MCP Server

Instructions

Implementation Reference

• src/services/medusa-store.ts:83-127 (handler)

  The core handler logic for the PostCartsIdComplete tool (and all store POST tools). It constructs query parameters and body from input, then uses the Medusa SDK to perform a POST request to the /carts/{id}/complete endpoint.
  handler: async ( input: InferToolHandlerInput<any, ZodTypeAny> ): Promise<any> => { const query = new URLSearchParams(input); const body = Object.entries(input).reduce( (acc, [key, value]) => { if ( parameters.find( (p) => p.name === key && p.in === "body" ) ) { acc[key] = value; } return acc; }, {} as Record<string, any> ); if (method === "get") { console.error( `Fetching ${refPath} with GET ${query.toString()}` ); const response = await this.sdk.client.fetch(refPath, { method: method, headers: { "Content-Type": "application/json", "Accept": "application/json", "Authorization": `Bearer ${process.env.PUBLISHABLE_KEY}` }, query: query }); return response; } else { const response = await this.sdk.client.fetch(refPath, { method: method, headers: { "Content-Type": "application/json", "Accept": "application/json", "Authorization": `Bearer ${process.env.PUBLISHABLE_KEY}` }, body: JSON.stringify(body) }); return response; } } };
• src/services/medusa-store.ts:54-82 (schema)

  Dynamically generates the input schema for PostCartsIdComplete using Zod schemas inferred from the OpenAPI spec parameters for the corresponding operation.
  inputSchema: { ...parameters .filter((p) => p.in != "header") .reduce((acc, param) => { switch (param.schema.type) { case "string": acc[param.name] = z.string().optional(); break; case "number": acc[param.name] = z.number().optional(); break; case "boolean": acc[param.name] = z.boolean().optional(); break; case "array": acc[param.name] = z .array(z.string()) .optional(); break; case "object": acc[param.name] = z.object({}).optional(); break; default: acc[param.name] = z.string().optional(); } return acc; }, {} as any) },
• src/index.ts:35-42 (registration)

  Registers the PostCartsIdComplete tool (among others from medusaStoreService.defineTools()) with the MCP server.
  tools.forEach((tool) => { server.tool( tool.name, tool.description, tool.inputSchema, tool.handler ); });
• src/services/medusa-store.ts:131-137 (helper)

  The method that iterates over the store OpenAPI spec to create tool definitions, including PostCartsIdComplete via wrapPath for the POST /carts/{id}/complete path.
  defineTools(store = storeJson): any[] { const paths = Object.entries(store.paths) as [string, SdkRequestType][]; const tools = paths.map(([path, refFunction]) => this.wrapPath(path, refFunction) ); return tools; }
• src/utils/define-tools.ts:21-59 (helper)

  Wrapper around the inner handler that formats the response as MCP-compliant text/JSON output or error, used for all tools including PostCartsIdComplete.
  const wrappedHandler = async ( input: InferToolHandlerInput<Zod.ZodAny, Zod.ZodAny>, _: RequestHandlerExtra ): Promise<{ content: CallToolResult["content"]; isError?: boolean; statusCode?: number; }> => { try { const result = await tool.handler(input); return { content: [ { type: "text", text: JSON.stringify(result, null, 2) } ] }; } catch (error) { return { content: [ { type: "text", text: `Error: ${ error instanceof Error ? error.message : String(error) }` } ], isError: true }; } }; return { ...tool, handler: wrappedHandler };