Connect an HTTP MCP client to thirds.ai

Use this guide when your client supports Streamable HTTP and custom request headers, including browser agents. Create an API key on the API keys page. Each successful PDF or static image costs one credit. If you use a named product, follow its page instead: Claude Code, Claude Desktop, Cursor, VS Code, Codex, Grok, ChatGPT, Warp, Zed, OpenCode, Antigravity, Lovable, Replit, or Hermes.

Configure the client

Use these connection values:

Many clients accept a configuration like this. Check your client's field names before you save it:

{
  "mcpServers": {
    "thirds": {
      "type": "http",
      "url": "https://thirds.ai/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY"
      }
    }
  }
}

Replace the placeholder through the client's secret store or environment variable feature. Do not save a real key in a shared file.

Test with HTTP

Save the following body as rpc.json:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2025-11-25",
    "capabilities": {},
    "clientInfo": { "name": "thirds-http-test", "version": "1.0" }
  }
}

Set THIRDS_API_KEY in your secret store or shell, then run:

curl https://thirds.ai/mcp \
  -H "Authorization: Bearer $THIRDS_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  --data-binary @rpc.json

The response selects a supported protocol version. Include that value in the MCP-Protocol-Version header on later requests. The main MCP guide gives complete initialize, tool list, render, and status examples.

FAQ

Does thirds.ai support SSE or a GET event stream?

No. Use Streamable HTTP and send one JSON-RPC object in each POST. The server returns JSON and does not keep a persistent session.

Which headers are required?

Send Authorization, Content-Type: application/json, and Accept: application/json, text/event-stream. After initialization, also send the selected MCP-Protocol-Version.

Can browser page code call the MCP URL?

No. Cross-origin browser requests are refused. Connect from an MCP client or your own server. Keep the API key outside browser code.