Gmail MCP

import { StdioClientTransport, StdioServerParameters } from '@modelcontextprotocol/sdk/client/stdio.js' import { StreamableHTTPClientTransport } from '@modelcontextprotocol/sdk/client/streamableHttp.js' import { JSONRPCMessage } from '@modelcontextprotocol/sdk/types.js' import path from 'path' const RESPONSE_TIMEOUT = 1_000 // 1s const START_DELAY = 1_000 // 1s const TEST_TIMEOUT = 10_000 // 10s const TOTAL_TOOLS = 64 const streamableClientUrl = new URL(`http://localhost:${process.env.PORT || 3000}/mcp`) jest.setTimeout(TEST_TIMEOUT) type ReadMessageType = { jsonrpc: string id: number result: { content?: { type: string text: string }[], tools?: any[] } } // In some tests the argument IDs in this object are modified, ensure the ID is always set per-test where relevant const jsonRpcMessage: Record<string, JSONRPCMessage> = { ping: { jsonrpc: "2.0", id: 1, method: "ping" }, pong: { jsonrpc: '2.0', id: 1, result: {} }, initialize: { jsonrpc: "2.0", id: 1, method: "initialize", params: { clientInfo: { name: "test-client", version: "1.0" }, protocolVersion: "2025-05-13", capabilities: {}, } }, toolsList: { jsonrpc: "2.0", id: 1, method: "tools/list" }, getProfile: { jsonrpc: "2.0", id: 1, method: "tools/call", params: { name: "get_profile" } }, createDraft: { jsonrpc: "2.0", id: 1, method: "tools/call", params: { name: "create_draft", arguments: { subject: "Test Subject", body: "Test Body", to: ["test@example.com"], cc: ["test@example.com"], bcc: ["test@example.com"] } } }, listDrafts: { jsonrpc: "2.0", id: 1, method: "tools/call", params: { name: "list_drafts", arguments: { } } }, getDraft: { jsonrpc: "2.0", id: 1, method: "tools/call", params: { name: "get_draft", arguments: { id: "test-id" } } }, updateDraft: { jsonrpc: "2.0", id: 1, method: "tools/call", params: { name: "update_draft", arguments: { id: "test-id", subject: "Updated Subject", body: "Updated Body", to: ["updated@example.com"], cc: ["updated@example.com"], bcc: ["updated@example.com"] } } }, deleteDraft: { jsonrpc: "2.0", id: 1, method: "tools/call", params: { name: "delete_draft", arguments: { id: "test-id" } } } } const delay = (ms: number) => new Promise(resolve => setTimeout(resolve, ms)) const sendPostRequest = async (message: JSONRPCMessage | JSONRPCMessage[], sessionId?: string) => ( fetch(streamableClientUrl, { method: "POST", headers: { "Content-Type": "application/json", Accept: "application/json, text/event-stream", ...(sessionId ? { "mcp-session-id": sessionId } : {}), }, body: JSON.stringify(message), }) ) const getSSEData = async (response: Response) => { const reader = response.body?.getReader() const { value } = await reader!.read() const text = new TextDecoder().decode(value) const dataLine = text.split('\n').find(line => line.startsWith('data:')) expect(dataLine).toBeDefined() return JSON.parse(dataLine!.slice(5).trim()) } describe('Gmail MCP', () => { let stdioClient: StdioClientTransport let streamableClient: StreamableHTTPClientTransport beforeAll(async () => { const serverParameters: StdioServerParameters = { command: "node", args: [path.resolve(__dirname, '../dist/index.js')], env: process.env as Record<string, string> } stdioClient = new StdioClientTransport(serverParameters) await stdioClient.start() streamableClient = new StreamableHTTPClientTransport(streamableClientUrl) }) afterAll(async () => { await stdioClient.close() }) describe('Stdio Transport', () => { let readMessages: ReadMessageType[] let errors: Error[] let draftId: string beforeAll(async () => { await delay(START_DELAY) stdioClient.onmessage = (message) => readMessages.push(message as ReadMessageType) stdioClient.onerror = (error) => errors.push(error) }) beforeEach(async () => { readMessages = [] errors = [] }) it('responds to ping', async () => { stdioClient.send(jsonRpcMessage.ping) await delay(RESPONSE_TIMEOUT) expect(readMessages).toHaveLength(1) expect(readMessages[0]).toEqual(jsonRpcMessage.pong) expect(errors).toHaveLength(0) }) it('returns a list of tools', async () => { stdioClient.send(jsonRpcMessage.toolsList) await delay(RESPONSE_TIMEOUT) expect(readMessages).toHaveLength(1) expect(readMessages[0].result.tools?.length).toEqual(TOTAL_TOOLS) }) it('can call the get_profile tool', async () => { stdioClient.send(jsonRpcMessage.getProfile) await delay(RESPONSE_TIMEOUT) expect(readMessages).toHaveLength(1) expect(readMessages[0].result.content?.length).toEqual(1) const firstMessage = JSON.parse(readMessages[0].result.content?.[0].text ?? '{}') expect(firstMessage.emailAddress).toBeDefined() expect(firstMessage.messagesTotal).toBeDefined() expect(firstMessage.historyId).toBeDefined() }) it('can call the create_draft tool', async () => { stdioClient.send(jsonRpcMessage.createDraft) await delay(RESPONSE_TIMEOUT) expect(readMessages).toHaveLength(1) expect(readMessages[0].result.content?.length).toEqual(1) draftId = JSON.parse(readMessages[0].result.content?.[0].text ?? '{}').id expect(draftId).toBeDefined() }) it('can call the list_drafts tool', async () => { stdioClient.send(jsonRpcMessage.listDrafts) await delay(RESPONSE_TIMEOUT) expect(readMessages).toHaveLength(1) expect(readMessages[0].result.content?.length).toEqual(1) const draftsList = JSON.parse(readMessages[0].result.content?.[0].text ?? '{}') const createdDraft = draftsList.find((draft: any) => draft.id === draftId) expect(createdDraft).toBeDefined() }) it('can call the get_draft tool', async () => { jsonRpcMessage.getDraft["params"].arguments.id = draftId // Beware this modifies the original object stdioClient.send(jsonRpcMessage.getDraft) await delay(RESPONSE_TIMEOUT) expect(readMessages).toHaveLength(1) expect(readMessages[0].result.content?.length).toEqual(1) const draftEmail = JSON.parse(readMessages[0].result.content?.[0].text ?? '{}') expect(draftEmail.message.labelIds).toContain("DRAFT") expect(draftEmail.message.snippet).toEqual("Test Body") }) it('can call the delete_draft tool', async () => { jsonRpcMessage.deleteDraft["params"].arguments.id = draftId // Beware this modifies the original object stdioClient.send(jsonRpcMessage.deleteDraft) await delay(RESPONSE_TIMEOUT) expect(readMessages).toHaveLength(1) expect(readMessages[0].result.content?.length).toEqual(1) }) }) describe('Streamable HTTP Transport', () => { let draftId: string it('responds to ping', async () => { const response = await sendPostRequest(jsonRpcMessage.ping) expect(response.status).toBe(200) const sseResponse = await getSSEData(response) expect(sseResponse).toEqual(jsonRpcMessage.pong) }) it('returns a list of tools', async () => { const response = await sendPostRequest(jsonRpcMessage.toolsList) expect(response.status).toBe(200) const sseResponse = await getSSEData(response) expect(sseResponse.result.tools?.length).toEqual(TOTAL_TOOLS) }) it('can call the get_profile tool', async () => { const response = await sendPostRequest(jsonRpcMessage.getProfile) expect(response.status).toBe(200) const sseResponse = await getSSEData(response) expect(sseResponse.result.content?.length).toEqual(1) const firstMessage = JSON.parse(sseResponse.result.content?.[0].text ?? '{}') expect(firstMessage.emailAddress).toBeDefined() expect(firstMessage.messagesTotal).toBeDefined() expect(firstMessage.historyId).toBeDefined() }) it('can call the create_draft tool', async () => { const response = await sendPostRequest(jsonRpcMessage.createDraft) expect(response.status).toBe(200) const sseResponse = await getSSEData(response) expect(sseResponse.result.content?.length).toEqual(1) draftId = JSON.parse(sseResponse.result.content?.[0].text).id expect(draftId).toBeDefined() }) it('can call the list_drafts tool', async () => { const response = await sendPostRequest(jsonRpcMessage.listDrafts) expect(response.status).toBe(200) const sseResponse = await getSSEData(response) expect(sseResponse.result.content?.length).toEqual(1) const draftsList = JSON.parse(sseResponse.result.content?.[0].text) const createdDraft = draftsList.find((draft: any) => draft.id === draftId) expect(createdDraft).toBeDefined() }) it('can call the get_draft tool', async () => { jsonRpcMessage.getDraft["params"].arguments.id = draftId // Beware this modifies the original object const response = await sendPostRequest(jsonRpcMessage.getDraft) expect(response.status).toBe(200) const getDraftSseResponse = await getSSEData(response) expect(getDraftSseResponse.result.content?.length).toEqual(1) const draftEmail = JSON.parse(getDraftSseResponse.result.content?.[0].text) expect(draftEmail.message.labelIds).toContain("DRAFT") expect(draftEmail.message.snippet).toEqual("Test Body") }) // it('can call the update_draft tool', async () => { // jsonRpcMessage.updateDraft["params"].arguments.id = draftId // Beware this modifies the original object // const response = await sendPostRequest(jsonRpcMessage.updateDraft) // expect(response.status).toBe(200) // const updateDraftSseResponse = await getSSEData(response) // expect(updateDraftSseResponse.result.content?.length).toEqual(1) // const updatedDraft = JSON.parse(updateDraftSseResponse.result.content?.[0].text) // console.log(updatedDraft) // expect(updatedDraft.message.labelIds).toContain("DRAFT") // // expect(updatedDraft.message.snippet).toEqual("Updated Body") // TODO this test fails, update before uncommenting the update_draft method // }) it('can call the delete_draft tool', async () => { jsonRpcMessage.deleteDraft["params"].arguments.id = draftId // Beware this modifies the original object const response = await sendPostRequest(jsonRpcMessage.deleteDraft) expect(response.status).toBe(200) const deleteDraftSseResponse = await getSSEData(response) expect(deleteDraftSseResponse.result.content?.length).toEqual(1) }) }) })