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Examples

1. CLI — web transport with the admin UI​

openapi-mcp serve \
  --transport web \
  --port 3000 \
  --host 127.0.0.1 \
  --api-key your-admin-key \
  --spec ./openapi.yaml \
  --base-url https://api.example.com

The admin console is served at /, the Streamable HTTP MCP endpoint at /mcp, and the legacy SSE endpoint at /sse.

2. Programmatic — stdio server​

import { loadOpenApiSpec, startStdioServer } from "@powerduck/openapi-mcp-server";

const spec = await loadOpenApiSpec("./openapi.yaml");

const handle = await startStdioServer(
  spec,
  {
    baseUrlOverride: "https://api.example.com",
    security: { bearerToken: process.env.UPSTREAM_TOKEN },
    requestTimeoutMs: 10000,
  },
  { handleSignals: true },
);

console.error("stdio MCP server ready");
await handle.closed;

3. Admin server with API-key auth​

import { startAdminServer } from "@powerduck/openapi-mcp-server/server";

const handle = await startAdminServer({
  port: 3000,
  host: "127.0.0.1",
  apiKey: process.env.ADMIN_API_KEY,
  specPath: "./openapi.yaml",
  allowedOrigins: ["https://your-console.example.com"],
  redactSensitiveHeaders: true,
  maxLogEntries: 500,
});

console.log("admin listening on", handle.port);
// ...
await handle.close();

4. Custom SpecProvider and context provider​

Build the MCP server by hand and mount it on your own Express app:

import express from "express";
import {
  attachMcpRoutes,
  loadOpenApiSpec,
} from "@powerduck/openapi-mcp-server";

let spec = await loadOpenApiSpec("./openapi.yaml");

// A provider that can be swapped at runtime without restarting sessions.
const specProvider = () => spec;
const contextProvider = () => ({
  baseUrlOverride: "https://api.example.com",
  security: { bearerToken: process.env.UPSTREAM_TOKEN },
});

const app = express();
app.use(express.json());

const routes = attachMcpRoutes(app, {
  specProvider,
  contextProvider,
  maxSessions: 64,
  sessionIdleMs: 600000,
});
console.log(routes.listSessions());

app.listen(8080, () => console.log("mcp on :8080/mcp"));

attachMcpRoutes is exported from the package root. Its options control session limits, CORS origins and idle cleanup; the returned handle exposes listSessions, closeSession, closeAll and dispose. Call dispose() during shutdown to stop the background sweeper and close sessions. Use startAdminServer when you also need the admin console.

5. Generate tools, prompts and resources from a spec​

import {
  loadOpenApiSpec,
  generateTools,
  generateToolsDetailed,
  buildBindingIndex,
  generatePrompts,
  generateResources,
  executeToolCall,
} from "@powerduck/openapi-mcp-server";

const spec = await loadOpenApiSpec("./openapi.yaml");

const tools = generateTools(spec);
console.log(tools.map((t) => t.name));

const detailed = generateToolsDetailed(spec);
console.log("issues:", detailed.issues);

const bindings = buildBindingIndex(spec); // toolName -> ToolBinding

console.log(generatePrompts(spec).map((p) => p.name));
console.log(generateResources(spec).map((r) => r.uri));

// Execute one generated tool directly.
const result = await executeToolCall(
  spec,
  "get_user",
  { id: "42" },
  { baseUrlOverride: "https://api.example.com" },
);
console.log(result.status, result.data);

6. Use auth middleware in your own Express app​

import express from "express";
import { createAuthMiddleware } from "@powerduck/openapi-mcp-server";

const app = express();
app.use("/admin", createAuthMiddleware(process.env.ADMIN_API_KEY));
app.get("/admin/status", (req, res) => res.json({ ok: true }));

Omitting the key disables the guard; an empty string throws rather than silently running open.

See also​