Connect Claude Code to thirds.ai

Use thirds.ai from Claude Code to build templates, create PDFs or images, and check their status. You need a thirds.ai API key from the API keys page.

Install the server

Set THIRDS_API_KEY in your shell or secret store. Then run this command. The single quotes keep the key out of the command and saved configuration.

claude mcp add --transport http --scope user thirds https://thirds.ai/mcp \
  --header 'Authorization: Bearer ${THIRDS_API_KEY}'

Claude Code supports remote HTTP servers and environment variable expansion in headers. The user scope makes the server available in all of your projects. Use --scope project if you want to share the server definition with one team.

You can also add this entry to a project .mcp.json file:

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

Keep THIRDS_API_KEY out of the JSON file and source control. This format follows the Claude Code MCP guide.

Check the connection

Run claude mcp get thirds, then open Claude Code and enter /mcp. The server must show as connected. Ask Claude to list the thirds.ai tools before you start paid work.

Read the main MCP guide before your first render. It explains credit approval, idempotency keys, status checks, and private content.

FAQ

Why does the server show as failed?

Check that THIRDS_API_KEY is set in the environment that starts Claude Code. Then check that the key is active and the URL is exactly https://thirds.ai/mcp.

Can I share this setup with my team?

Yes. Use project scope or commit the .mcp.json file. Each person must set their own THIRDS_API_KEY. Never commit a key.

Does connecting spend credits?

No. Connecting and listing tools don't spend credits. AI template work and successful renders can. Ask your agent to show the action and the cost before it starts paid work.