Credential for authentication.
str or :class:~azure.core.credentials.AzureKeyCredential
is treated as an Anthropic API key.~azure.core.credentials.TokenCredential (e.g.
:class:~azure.identity.DefaultAzureCredential) or
:class:~azure.core.credentials_async.AsyncTokenCredential (e.g.
:class:~azure.identity.aio.DefaultAzureCredential) is used as a
callable bearer-token provider so that tokens are refreshed
automatically.None (default) falls back to
:class:~azure.identity.DefaultAzureCredential.