Advanced MCP Features

import fs from 'node:fs/promises' import path from 'node:path' import { invariant } from '@epic-web/invariant' import { faker } from '@faker-js/faker' import { Client } from '@modelcontextprotocol/sdk/client/index.js' import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js' import { ElicitRequestSchema } from '@modelcontextprotocol/sdk/types.js' import { test, expect } from 'vitest' function getTestDbPath() { return `./test.ignored/db.${process.env.VITEST_WORKER_ID}.${Math.random().toString(36).slice(2)}.sqlite` } async function setupClient({ capabilities = {} } = {}) { const EPIC_ME_DB_PATH = getTestDbPath() const dir = path.dirname(EPIC_ME_DB_PATH) await fs.mkdir(dir, { recursive: true }) const client = new Client( { name: 'EpicMeTester', version: '1.0.0', }, { capabilities }, ) const transport = new StdioClientTransport({ command: 'tsx', args: ['src/index.ts'], stderr: 'ignore', env: { ...process.env, EPIC_ME_DB_PATH, }, }) await client.connect(transport) return { client, EPIC_ME_DB_PATH, async [Symbol.asyncDispose]() { await client.transport?.close() // give things a moment to release locks and whatnot await new Promise((r) => setTimeout(r, 100)) await fs.unlink(EPIC_ME_DB_PATH).catch(() => {}) // ignore missing file }, } } test('Tool Definition', async () => { await using setup = await setupClient() const { client } = setup const list = await client.listTools() const [firstTool] = list.tools invariant(firstTool, '🚨 No tools found') expect(firstTool, '🚨 firstTool should be a create_entry tool').toEqual( expect.objectContaining({ name: expect.stringMatching(/^create_entry$/i), description: expect.stringMatching(/^create a new journal entry$/i), inputSchema: expect.objectContaining({ type: 'object', properties: expect.objectContaining({ title: expect.objectContaining({ type: 'string', description: expect.stringMatching(/title/i), }), content: expect.objectContaining({ type: 'string', description: expect.stringMatching(/content/i), }), }), }), }), ) }) test('Tool annotations and structured output', async () => { await using setup = await setupClient() const { client } = setup // Check create_entry and create_tag annotations (always enabled) let list = await client.listTools() let toolMap = Object.fromEntries(list.tools.map((t) => [t.name, t])) // Check create_entry annotations const createEntryTool = toolMap['create_entry'] invariant(createEntryTool, '🚨 create_entry tool not found') expect( createEntryTool.annotations, '🚨 create_entry missing annotations', ).toEqual( expect.objectContaining({ destructiveHint: false, openWorldHint: false, }), ) // Check create_entry outputSchema expect( createEntryTool.outputSchema, '🚨 create_entry missing outputSchema', ).toBeDefined() // Check create_tag annotations const createTagTool = toolMap['create_tag'] invariant(createTagTool, '🚨 create_tag tool not found') expect( createTagTool.annotations, '🚨 create_tag missing annotations', ).toEqual( expect.objectContaining({ destructiveHint: false, openWorldHint: false, }), ) // Check create_tag outputSchema expect( createTagTool.outputSchema, '🚨 create_tag missing outputSchema', ).toBeDefined() // Create a tag and entry for further tool calls const tagResult = await client.callTool({ name: 'create_tag', arguments: { name: 'TestTag', description: 'A tag for testing', }, }) expect( tagResult.structuredContent, '🚨 tagResult.structuredContent should be defined', ).toBeDefined() const tag = (tagResult.structuredContent as any).tag invariant(tag, '🚨 No tag resource found') invariant(tag.id, '🚨 No tag ID found') const entryResult = await client.callTool({ name: 'create_entry', arguments: { title: 'Test Entry', content: 'This is a test entry', }, }) expect( entryResult.structuredContent, '🚨 entryResult.structuredContent should be defined', ).toBeDefined() const entry = (entryResult.structuredContent as any).entry invariant(entry, '🚨 No entry resource found') invariant(entry.id, '🚨 No entry ID found') // List tools again now that entry and tag exist list = await client.listTools() toolMap = Object.fromEntries(list.tools.map((t) => [t.name, t])) // Check delete_entry annotations and outputSchema const deleteEntryTool = toolMap['delete_entry'] invariant(deleteEntryTool, '🚨 delete_entry tool not found') expect( deleteEntryTool.annotations, '🚨 delete_entry missing annotations', ).toEqual(expect.objectContaining({ openWorldHint: false })) expect( deleteEntryTool.outputSchema, '🚨 delete_entry missing outputSchema', ).toBeDefined() // Check delete_tag annotations and outputSchema const deleteTagTool = toolMap['delete_tag'] invariant(deleteTagTool, '🚨 delete_tag tool not found') expect( deleteTagTool.annotations, '🚨 delete_tag missing annotations', ).toEqual(expect.objectContaining({ openWorldHint: false })) expect( deleteTagTool.outputSchema, '🚨 delete_tag missing outputSchema', ).toBeDefined() // Test structured content in responses // get_entry structuredContent const getEntryResult = await client.callTool({ name: 'get_entry', arguments: { id: entry.id }, }) const getEntryContent = (getEntryResult.structuredContent as any).entry invariant(getEntryContent, '🚨 get_entry missing entry in structuredContent') expect(getEntryContent.id, '🚨 get_entry structuredContent.id mismatch').toBe( entry.id, ) // get_tag structuredContent const getTagResult = await client.callTool({ name: 'get_tag', arguments: { id: tag.id }, }) const getTagContent = (getTagResult.structuredContent as any).tag invariant(getTagContent, '🚨 get_tag missing tag in structuredContent') expect(getTagContent.id, '🚨 get_tag structuredContent.id mismatch').toBe( tag.id, ) // update_entry structuredContent const updateEntryResult = await client.callTool({ name: 'update_entry', arguments: { id: entry.id, title: 'Updated Entry' }, }) const updateEntryContent = (updateEntryResult.structuredContent as any).entry invariant( updateEntryContent, '🚨 update_entry missing entry in structuredContent', ) expect( updateEntryContent.title, '🚨 update_entry structuredContent.title mismatch', ).toBe('Updated Entry') // update_tag structuredContent const updateTagResult = await client.callTool({ name: 'update_tag', arguments: { id: tag.id, name: 'UpdatedTag' }, }) const updateTagContent = (updateTagResult.structuredContent as any).tag invariant(updateTagContent, '🚨 update_tag missing tag in structuredContent') expect( updateTagContent.name, '🚨 update_tag structuredContent.name mismatch', ).toBe('UpdatedTag') }) test('Elicitation: delete_tag decline', async () => { await using setup = await setupClient({ capabilities: { elicitation: {} } }) const { client } = setup // Set up a handler for elicitation requests client.setRequestHandler(ElicitRequestSchema, () => { return { action: 'decline', } }) // Create a tag to delete const tagResult = await client.callTool({ name: 'create_tag', arguments: { name: 'Elicit Test Tag', description: 'Testing elicitation decline.', }, }) const tag = (tagResult.structuredContent as any).tag invariant(tag, '🚨 No tag resource found') invariant(tag.id, '🚨 No tag ID found') // Delete the tag, which should trigger elicitation and be declined const deleteResult = await client.callTool({ name: 'delete_tag', arguments: { id: tag.id }, }) const structuredContent = deleteResult.structuredContent as any expect( structuredContent.success, '🚨 structuredContent.success should be false after declining to delete a tag', ).toBe(false) }) test('Elicitation: delete_tag confirmation', async () => { await using setup = await setupClient({ capabilities: { elicitation: {} } }) const { client } = setup // Set up a handler for elicitation requests let elicitationRequest: any client.setRequestHandler(ElicitRequestSchema, (req) => { elicitationRequest = req // Simulate user accepting the confirmation return { action: 'accept', content: { confirmed: true }, } }) // Create a tag to delete const tagResult = await client.callTool({ name: 'create_tag', arguments: { name: 'Elicit Test Tag 2', description: 'Testing elicitation acceptance.', }, }) const tag = (tagResult.structuredContent as any).tag invariant(tag, '🚨 No tag resource found') invariant(tag.id, '🚨 No tag ID found') // Delete the tag, which should trigger elicitation const deleteResult = await client.callTool({ name: 'delete_tag', arguments: { id: tag.id }, }) const structuredContent = deleteResult.structuredContent as any invariant( structuredContent, '🚨 No structuredContent returned from delete_tag', ) invariant( 'success' in structuredContent, '🚨 structuredContent missing success field', ) expect( structuredContent.success, '🚨 structuredContent.success should be true after accepting deletion of a tag', ).toBe(true) invariant(elicitationRequest, '🚨 No elicitation request was sent') const params = elicitationRequest.params invariant(params, '🚨 elicitationRequest missing params') expect( params.message, '🚨 elicitationRequest.params.message should match expected confirmation prompt', ).toMatch(/Are you sure you want to delete tag/i) expect( params.requestedSchema, '🚨 elicitationRequest.params.requestedSchema should match expected schema', ).toEqual( expect.objectContaining({ type: 'object', properties: expect.objectContaining({ confirmed: expect.objectContaining({ type: 'boolean' }), }), }), ) })