MCPX MCP Gateway

// src/runSingleStep.ts import type { Step } from './types'; import { extractText } from './utils'; import { SSEClientTransport } from '@modelcontextprotocol/sdk/client/sse.js'; import { Client } from '@modelcontextprotocol/sdk/client/index.js'; import type { AiAgentController, ToolCallableAgentController } from './aiAgents/types'; function isToolCallableAgent( controller?: AiAgentController ): controller is ToolCallableAgentController { return !!controller && typeof (controller as ToolCallableAgentController).callTool === 'function'; } function extractPrimaryResult(text: string): string | undefined { if (!text) return undefined; const match = text.match(/### Result\s+([\s\S]*?)(?:\n###|$)/); if (!match) return undefined; return match[1].trim(); } /** * Run ONE step and return plain text for validation. * • backend → returns concatenated text blocks from tool result * • browser → takes a snapshot after the action and returns JSON-stringified snapshot * • sharedClient/transport can be used to reuse the same connection for browser steps. */ export async function runSingleStep( step: Step, baseUrl: string, sharedClient?: Client, sharedTransport?: SSEClientTransport, scenarioDefaultVerbose = false, agentController?: AiAgentController ): Promise<string> { const wantLog = step.verboseOutput ?? scenarioDefaultVerbose; if (step.kind === 'agent') { if (!isToolCallableAgent(agentController)) { throw new Error('Scenario requires an aiAgent that supports on-demand tool calls.'); } const msg = wantLog ? ` → Running agent tool "${step.toolName}" with payload: ${JSON.stringify(step.payload)}` : ` → Running agent tool "${step.toolName}"`; console.log(msg); try { return await agentController.callTool({ toolName: step.toolName, payload: step.payload, verbose: wantLog, }); } catch (err: any) { if (step.expectError) { const message = err?.message ?? String(err); console.log(`✔ [${step.name}] expected error:`, message); return message; } throw err; } } let client: Client; let transport: SSEClientTransport; if (step.kind === 'browser') { // Reuse the pre-connected client/transport if (!sharedClient || !sharedTransport) { throw new Error('Browser client not initialized'); } client = sharedClient; transport = sharedTransport; } else { // backend: create a fresh transport for /sse each time const url = `${baseUrl}/sse`; console.log(` → Connecting to MCP server at ${url}`); transport = new SSEClientTransport(new URL(url)); client = new Client({ name: 'e2e-test', version: '1.0.0' }); await client.connect(transport); } /* ── run the requested tool ───────────────────────────────────────── */ const msg = wantLog ? ` → Running ${step.kind} tool "${step.toolName}" with payload: ${JSON.stringify( step.payload )}` : ` → Running ${step.kind} tool "${step.toolName}"`; console.log(msg); let toolResult; try { toolResult = await client.callTool({ name: step.toolName, arguments: step.payload, }); } catch (err: any) { if (step.expectError) { console.log(`✔ [${step.name}] expected error:`, err.message || err); return err.message; } // rethrow if this wasn’t expected throw err; } /* ---------- browser snapshot / backend text ---------- */ if (step.kind === 'browser') { const text = extractText(toolResult); const primary = extractPrimaryResult(text); const finalText = primary ?? text; if (wantLog && finalText) { console.log(' ← Tool output:', finalText.trim()); } return finalText || ''; } /* ── backend: extract raw text blocks from tool result ────────────── */ const text = extractText(toolResult); const primary = extractPrimaryResult(text); const finalText = primary ?? text; if (wantLog && finalText) { console.log(' ← Tool output:', finalText.trim()); } return finalText; }