Step 2: Set a Default Audience

By default, Claude (like other MCP clients) includes `resource` as a parameter in the OAuth authorization request but does not include `audience.’ When Auth0 doesn’t receive an audience, it issues opaque (encrypted) tokens. These are difficult to validate in an MCP server, since decryption typically requires keypairs and support that may not exist.

Setting a default audience ensures Auth0 produces a standard JWT access token that your MCP server can validate.

Treat this as a shortcut, it is best suited for demos or non-production setups.

1. In the Auth0 dashboard, go to APIs
2. Click on + Create API
3. Enter a friendly name under Name (for example, “My MCP Server”)
4. Enter https://mymcpserver.com/ under Identifier
5. Click Save