Authentication

Obtain a PolyAI API key and configure your MCP client to authenticate against the Builder MCP.

PolyAI’s MCP servers authenticate with the same workspace-scoped API key used across PolyAI’s APIs, sent in the X-API-KEY header.

Get an API key

1. Open the API Keys page

   Go to the API Keys tab on your workspace homepage in Agent Studio. See API keys for details.

2. Create a key

   Select API key, name it, choose the agents it can access, and set its permissions. Scope it to the least it needs — see Security & safe use.

3. Copy the value

   The full key is shown only once. Copy it immediately and store it in your client’s secret settings — never paste it into a chat prompt.

The API Keys tab on your workspace homepage in Agent Studio.

Configure your client

Pass the key in the X-API-KEY header. The MCP server uses the streamable HTTP transport, so clients also send an Accept header:

Header	Value
X-API-KEY	Your workspace-scoped API key
Accept	application/json, text/event-stream

Most clients set Accept automatically. See Quickstart for per-client configuration.

Pick your region

PolyAI runs the MCP server in every region, on the same host family as the platform APIs. Your API key is scoped to a workspace, and each workspace lives in one region — connect to the matching endpoint.

Region	Endpoint
US	https://api.us.poly.ai/builder-mcp
UK	https://api.uk.poly.ai/builder-mcp
EU	https://api.eu.poly.ai/builder-mcp
Studio	https://api.studio.poly.ai/builder-mcp

OAuth (coming soon)

Browser-based OAuth is on the roadmap — you’ll be able to authorize a client without manually creating and pasting a key. At launch, use API-key authentication as described above. This page will cover OAuth once it ships.