Marketo MCP Server

Implementation Reference

• src/index.ts:383-412 (registration)

  Registration of the 'marketo_get_lead_by_id' tool using McpServer.tool(). Includes inline Zod schema for parameters (leadId required number, fields optional string array) and the complete inline async handler function. The handler builds the Marketo REST API endpoint /rest/v1/lead/{leadId}.json with optional 'fields' query parameter, calls the makeApiRequest helper to fetch data, formats the response as JSON text content, or returns an error message on failure.
  server.tool( 'marketo_get_lead_by_id', { leadId: z.number(), fields: z.array(z.string()).optional(), }, async ({ leadId, fields }) => { try { const params = new URLSearchParams(); if (fields) { params.append('fields', fields.join(',')); } const response = await makeApiRequest( `/rest/v1/lead/${leadId}.json${params.toString() ? `?${params.toString()}` : ''}`, 'GET' ); return { content: [{ type: 'text', text: JSON.stringify(response, null, 2) }], }; } catch (error: any) { return { content: [ { type: 'text', text: `Error: ${error.response?.data?.message || error.message}` }, ], }; } } );
• src/index.ts:22-52 (helper)

  Core helper function called by the tool handler to execute authenticated HTTP requests to Marketo API. Retrieves Bearer token via TokenManager, sets headers, uses axios for the request (handling form-urlencoded data), returns response.data, and re-throws errors after logging.
  async function makeApiRequest( endpoint: string, method: string, data?: any, contentType: string = 'application/json' ) { const token = await tokenManager.getToken(); const headers: any = { Authorization: `Bearer ${token}`, }; if (contentType) { headers['Content-Type'] = contentType; } try { const response = await axios({ url: `${MARKETO_BASE_URL}${endpoint}`, method: method, data: contentType === 'application/x-www-form-urlencoded' ? new URLSearchParams(data).toString() : data, headers, }); return response.data; } catch (error: any) { console.error('API request failed:', error.response?.data || error.message); throw error; } }
• src/auth.ts:11-52 (helper)

  TokenManager class provides getToken() method for obtaining and caching OAuth2 access tokens using client credentials flow against Marketo's identity endpoint. Used by makeApiRequest to authenticate all API calls. Instantiated globally with env vars.
  class TokenManager { private clientId: string; private clientSecret: string; private accessToken: string | null = null; private tokenExpiry: number = 0; constructor(clientId: string, clientSecret: string) { this.clientId = clientId; this.clientSecret = clientSecret; } async getToken(): Promise<string> { // Check if we have a valid token if (this.accessToken && Date.now() < this.tokenExpiry) { return this.accessToken; } try { // Extract the identity URL from the base URL // Convert from https://instance.mktorest.com/rest to https://instance.mktorest.com/identity const identityUrl = MARKETO_BASE_URL.replace('/rest', '/identity'); const response = await axios.get(`${identityUrl}/oauth/token`, { params: { grant_type: 'client_credentials', client_id: this.clientId, client_secret: this.clientSecret, }, }); const data = response.data as TokenResponse; this.accessToken = data.access_token; // Set expiry to slightly before the actual expiry to ensure we don't use an expired token this.tokenExpiry = Date.now() + (data.expires_in - 60) * 1000; return this.accessToken; } catch (error: any) { console.error('Failed to get Marketo access token:', error.response?.data || error.message); throw new Error('Failed to authenticate with Marketo'); } } }