mcpGraph

/** * MCP tool node executor */ import type { McpNode, ServerConfig } from "../../types/config.js"; import type { ExecutionContext } from "../context.js"; import { evaluateJsonata } from "../../expressions/jsonata.js"; import type { McpClientManager } from "../../mcp/client-manager.js"; import { logger } from "../../logger.js"; export async function executeMcpToolNode( node: McpNode, context: ExecutionContext, clientManager: McpClientManager, serverConfig: ServerConfig, startTime: number ): Promise<{ output: unknown; nextNode: string }> { logger.debug(`Executing MCP tool node: ${node.id} (${node.server}.${node.tool})`); const exprContext = context.getData(); // Pre-transform: Apply JSONata to format tool arguments const transformedArgs: Record<string, unknown> = {}; for (const [key, value] of Object.entries(node.args)) { if (typeof value === "string" && value.startsWith("$")) { // JSONata expression const evaluated = await evaluateJsonata(value, exprContext); transformedArgs[key] = evaluated; logger.debug(`JSONata "${value}" evaluated to: ${JSON.stringify(evaluated)}`); } else { transformedArgs[key] = value; } } logger.debug(`MCP tool args: ${JSON.stringify(transformedArgs, null, 2)}`); logger.debug(`Expression context: ${JSON.stringify(exprContext, null, 2)}`); // Get or create MCP client using server configuration const client = await clientManager.getClient(node.server, serverConfig); // Call the tool const result = await client.callTool({ name: node.tool, arguments: transformedArgs as Record<string, unknown>, }); if (result.isError) { const content = result.content as Array<{ text?: string }>; throw new Error(`MCP tool error: ${content[0]?.text || "Unknown error"}`); } // Extract result content const content = result.content as Array<{ text?: string } | unknown>; let toolOutput: unknown; if (content[0] && typeof content[0] === "object" && "text" in content[0]) { const textContent = (content[0] as { text?: string }).text; if (textContent) { try { toolOutput = JSON.parse(textContent); } catch { toolOutput = textContent; } } else { toolOutput = content[0]; } } else { toolOutput = content[0]; } logger.debug(`MCP tool output: ${JSON.stringify(toolOutput, null, 2)}`); const output = toolOutput; const endTime = Date.now(); context.setNodeOutput(node.id, output); context.addHistory(node.id, "mcp", transformedArgs, output, startTime, endTime); return { output, nextNode: node.next, }; }