MCP Workbench MCP Server

Instructions

Implementation Reference

• src/tools/inspectServer.ts:36-78 (handler)

  The core implementation of the inspect_server tool, which runs CLI commands to inspect an MCP server.

  export async function inspectServer(
    input: InspectServerInput,
  ): Promise<InspectServerOutput> {
    const args = buildArgs(input);
    const result = await runCli(args, { timeoutMs: input.timeoutMs });
  
    const session: NegotiatedSession = JSON.parse(result.stdout);
  
    const caps = session.serverCapabilities;
    const capabilities = {
      tools: "tools" in caps,
      resources: "resources" in caps,
      prompts: "prompts" in caps,
      completions: "completions" in caps,
      logging: "logging" in caps,
    };
  
    const structured: InspectServerOutput["structured"] = {
      serverName: session.serverInfo.name,
      serverVersion: session.serverInfo.version,
      protocolVersion: session.protocolVersion,
      capabilities,
    };
    if (session.serverInstructions) {
      structured.instructions = session.serverInstructions;
    }
  
    const capLines = (
      ["tools", "resources", "prompts", "completions", "logging"] as const
    )
      .map((c) => `  ${capabilities[c] ? "\u2713" : "\u25CB"} ${c}`)
      .join("\n");
  
    const text = [
      `Server: ${structured.serverName} v${structured.serverVersion}`,
      `Protocol: ${structured.protocolVersion}`,
      "",
      "Capabilities:",
      capLines,
    ].join("\n");
  
    return { text, structured };
  }

• src/tools/inspectServer.ts:3-10 (schema)

  Input and output interface definitions for the inspect_server tool.

  export interface InspectServerInput {
    transport: "stdio" | "streamable-http";
    url?: string;
    command?: string;
    args?: string | string[];
    headers?: Record<string, string>;
    timeoutMs?: number;
  }

• src/server.ts:221-228 (registration)

  The request handler registration where inspect_server is mapped to its execution function.

  case "inspect_server": {
    const output = await inspectServer(
      args as unknown as Parameters<typeof inspectServer>[0],
    );
    return {
      content: [{ type: "text" as const, text: output.text }],
    };
  }