Google Vertex AI provider implementation.

Supports Vertex AI's unified API for accessing multiple AI models including:

• Anthropic Claude models (claude-haiku-4-5, claude-sonnet-4-5, claude-opus-4-1)
• Google Gemini models (gemini-2.0-flash, gemini-2.5-flash, gemini-2.5-pro)
• And more as Google adds them

Authentication

Vertex AI uses Google Cloud OAuth2 authentication with service accounts.

Service Account (Recommended)

# Option 1: Environment variables
export GOOGLE_APPLICATION_CREDENTIALS="/path/to/service-account.json"
export GOOGLE_CLOUD_PROJECT="your-project-id"
export GOOGLE_CLOUD_REGION="us-central1"

# Option 2: Pass directly in options
ReqLLM.generate_text(
  "google-vertex:claude-haiku-4-5@20251001",
  "Hello",
  provider_options: [
    service_account_json: "/path/to/service-account.json",
    project_id: "your-project-id",
    region: "us-central1"
  ]
)

Examples

# Simple text generation with Claude on Vertex
{:ok, response} = ReqLLM.generate_text(
  "google-vertex:claude-haiku-4-5@20251001",
  "Hello!"
)

# Streaming
{:ok, response} = ReqLLM.stream_text(
  "google-vertex:claude-haiku-4-5@20251001",
  "Tell me a story"
)

Extending for New Models

To add support for a new model family:

1. Add the model family to @model_families
2. Implement the formatter module (e.g., ReqLLM.Providers.GoogleVertex.Gemini)
3. The formatter needs:
   • format_request/3 - Convert ReqLLM context to provider format
   • parse_response/2 - Convert provider response to ReqLLM format
   • extract_usage/2 - Extract usage information