Use with any MCP client - UniversalBench

If your AI client supports MCP, it works with UniversalBench. The protocol is open and the connection details are always the same: one URL.

Connection details

Field	Value
Personal MCP URL	`https://universalbench-mcp.penantiaglobal.workers.dev/u/ubk_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx`
Protocol	MCP over HTTP (Streamable HTTP transport)
Auth	Baked into the URL path
Content type	`application/json`
Accept header	`application/json, text/event-stream`
MCP tools	`ub_read` (reads), `ub_write` (code and writes), `ub_ai` (AI and web)

Confirmed working clients

Continue

Open source AI coding assistant. Add UB to ~/.continue/config.json under mcpServers with a url field.

Zed Editor

Set up via Zed’s MCP extension. Paste your URL. UB appears in the assistant panel.

Cline (VS Code)

Add UB under “MCP Servers” in Cline’s settings panel with the URL field only.

Anything MCP

Any agentic builder that supports MCP. Paste your URL in their integrations panel.

Your own agent

Build with @modelcontextprotocol/sdk (Node) or mcp (Python). See below.

Build your own agent in Python

from mcp import ClientSession
from mcp.client.streamable_http import streamablehttp_client

async with streamablehttp_client("https://universalbench-mcp.penantiaglobal.workers.dev/u/ubk_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx") as (read, write, _):
    async with ClientSession(read, write) as session:
        await session.initialize()

        tools = await session.list_tools()
        # tools are: ub_read, ub_write, ub_ai

        result = await session.call_tool(
            "ub_write",
            {"code": "print(sum(range(1000)))"}
        )
        print(result.content)

Build your own agent in Node and TypeScript

import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StreamableHTTPClientTransport } from "@modelcontextprotocol/sdk/client/streamableHttp.js";

const transport = new StreamableHTTPClientTransport(
  new URL("https://universalbench-mcp.penantiaglobal.workers.dev/u/ubk_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")
);

const client = new Client(
  { name: "my-agent", version: "1.0.0" },
  { capabilities: {} }
);
await client.connect(transport);

const tools = await client.listTools();

const result = await client.callTool({
  name: "ub_write",
  arguments: { code: "print('hello from my agent')" }
});

Direct JSON RPC without an MCP SDK

If you cannot or do not want to use the MCP protocol library, post JSON RPC envelopes to the URL directly:

curl -X POST https://universalbench-mcp.penantiaglobal.workers.dev/u/ubk_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "ub_write",
      "arguments": {
        "code": "import requests; print(requests.get(\"https://api.github.com\").status_code)"
      }
    }
  }'

The response is a server sent event with the JSON RPC result, or the result inline as JSON depending on your Accept header.

Alternative authentication

If you cannot embed the token in the URL path for some reason (rare), the API also accepts:

Authorization: Bearer ubk_your_key_here
X-Api-Key: ubk_your_key_here
?key=ubk_your_key_here query parameter

The path embedded URL is preferred because it works in every MCP client without configuration.

​Connection details

​Confirmed working clients