[ docs ]MCP · SDK
OpenAI API and Agents SDK
The Responses API's hosted MCP tool, or HostedMCPTool in the Agents SDK.
API key
Setup
Responses API: declare the server as a tool with the key as authorization.
Pythonfrom openai import OpenAI import os client = OpenAI() response = client.responses.create( model="gpt-5", input="Who are the top commenters on r/python this week?", tools=[{ "type": "mcp", "server_label": "zomler", "server_url": "https://api.zomler.com/mcp", "authorization": os.environ["ZOMLER_API_KEY"], "require_approval": "never", }], )Agents SDK: the same server as a HostedMCPTool on the agent.
Agents SDKfrom agents import Agent, HostedMCPTool agent = Agent( name="analyst", tools=[HostedMCPTool(tool_config={ "type": "mcp", "server_label": "zomler", "server_url": "https://api.zomler.com/mcp", "authorization": os.environ["ZOMLER_API_KEY"], "require_approval": "never", })], )
What you get
One tool per platform, plus capabilities and check_balance, at https://api.zomler.com/mcp. Every answer is the envelope: what was measured, when, what was left out and why, and what it cost. Fresh fetches spend credits; anything already held is free.
Keys are created under API keys in the dashboard, where each one's calls and spend are listed. Revoking a key stops this client on its next call. The same key also calls the REST API.