{
  "vertex_facts": [
    {
      "id": "vtx_auth_gcp_iam",
      "model_id": null,
      "model_family": "all models",
      "category": "auth differences",
      "description": "Authentication to Claude on Vertex AI uses standard Google Cloud IAM (service account credentials, Application Default Credentials, or short-lived OAuth2 access tokens obtained via gcloud/ADC), not a portable ANTHROPIC_API_KEY -- the same shape of difference as Bedrock's AWS SigV4/IAM auth relative to the direct API, but using Google's credential system instead of AWS's.",
      "source_url": "https://cloud.google.com/vertex-ai/generative-ai/docs/partner-models/use-claude",
      "created_at": "2026-07-02 08:29:30",
      "cite_as": "https://subagentvertex.com/api/vertex-facts/vtx_auth_gcp_iam"
    }
  ]
}