Opper MCP server

Sign up needs no credit card: you get an API key straight away and the free models work in the playground and the API. Add a card to use premium models, pay-as-you-go with no minimum.

Look up models without an account

Two of the server's tools need no account and no sign-in: list_models searches the model catalogue by name, type, provider or capability, and get_guide returns short setup guides. Everything that touches your account needs you to approve the connection in the browser first.

Call list_models with, for example:

{"type":"llm","limit":3}

Every argument is optional: q, type, provider, capability, deprecated, include, sort, order, limit and offset. Leave out the filters you are not using rather than sending empty or placeholder values, and if a filtered search comes back empty, retry with only limit. The results are the public catalogue. What your own account may call is a separate question, answered after the sign-in.

get_guide takes a topic: getting_started, connect_app, structured_output, rules or debugging.

Some MCP clients connect and list the server's tools before you have signed in. The two public tools work at that point. The rest need the browser approval first.

No MCP client? The model catalogue is public JSON at https://api.opper.ai/v3/models, no API key needed. Filter it with query parameters, for example ?type=llm&limit=3, and page through it with limit and offset. Use it when you can fetch a URL but cannot connect to an MCP server. Route and policy detail (include=route, include=policy) needs an API key. Try https://api.opper.ai/v3/models?type=llm&limit=3.

Connect your agent

Add a remote (HTTP) MCP server with the URL https://api.opper.ai/mcp. Leave out any API key and any scope list: the client opens a browser window where you sign in and choose the permissions.

Server URL: https://api.opper.ai/mcp. It speaks MCP over Streamable HTTP and signs you in with OAuth. It is on the API host, not on opper.ai.

OpenCode

Tested with OpenCode 1.18. Add this to opencode.json, then run opencode mcp auth opper:

{
  "mcp": {
    "opper": {
      "type": "remote",
      "url": "https://api.opper.ai/mcp",
      "enabled": true
    }
  }
}

Other clients

Any MCP client that supports remote servers with OAuth sign-in can use the URL above. OpenCode is the one we have tested end to end so far.

What happens when you connect

1. Your agent asks to connect and your browser opens platform.opper.ai.
2. You sign in, or create an account if you do not have one. No card is asked for.
3. You pick the organization and what the agent may do. Read only is selected to begin with. Build and manage adds projects, API keys, rules, routes and model calls. Deleting projects is a separate choice.
4. The agent continues on its own. Nothing is pasted into the conversation.

What the agent can do

• Before you connect: search the model catalog and read short setup guides. These two tools need no account.
• Create a project and an API key. The key's secret stays on the server unless you ask for it, and the agent can make calls with the key through the MCP server.
• Check that a model is available to you, then make a real call. gemini/gemma-4-31b is a free model, so it works before you add a card.
• Read usage, costs and traces.
• Create and change rules and custom routes, where your plan includes them.

Billing, adding a card and managing members stay in the dashboard.

Staying in control

• The agent acts as you, in the one organization you picked, with only the permissions you ticked. A new permission needs a new approval in the browser.
• See and disconnect your agents at platform.opper.ai/mcp/connections. A disconnected agent stops working on its next request.
• Disconnecting an agent does not delete API keys it created. Delete those under Settings, API keys.

Not the documentation server

Opper also runs a separate MCP server for searching the documentation, at https://docs.opper.ai/mcp. It needs no sign-in and cannot see or change your account. Use it when an agent needs to look something up, and the server on this page when it needs to do something.

New to Opper? Start at opper.ai/sign-up/free, browse models at opper.ai/models, or read the docs at docs.opper.ai.