WIP: feat: add google vertex support

Author: andreynering

google/google.go

@@ -24,17 +24,21 @@ type provider struct {
 }
 
 type options struct {
-	apiKey  string
-	name    string
-	headers map[string]string
-	client  *http.Client
+	apiKey   string
+	name     string
+	headers  map[string]string
+	client   *http.Client
+	backend  genai.Backend
+	project  string
+	location string
 }
 
 type Option = func(*options)
 
 func New(opts ...Option) ai.Provider {
 	options := options{
 		headers: map[string]string{},
+		backend: genai.BackendGeminiAPI,
 	}
 	for _, o := range opts {
 		o(&options)
@@ -71,6 +75,14 @@ func WithHTTPClient(client *http.Client) Option {
 	}
 }
 
+func WithVertex(project, location string) Option {
+	return func(o *options) {
+		o.backend = genai.BackendVertexAI
+		o.project = project
+		o.location = location
+	}
+}
+
 func (*provider) Name() string {
 	return Name
 }
@@ -94,8 +106,10 @@ type languageModel struct {
 func (g *provider) LanguageModel(modelID string) (ai.LanguageModel, error) {
 	cc := &genai.ClientConfig{
 		APIKey:     g.options.apiKey,
-		Backend:    genai.BackendGeminiAPI,
 		HTTPClient: g.options.client,
+		Backend:    g.options.backend,
+		Project:    g.options.project,
+		Location:   g.options.location,
 	}
 	client, err := genai.NewClient(context.Background(), cc)
 	if err != nil {

providertests/.env.sample

@@ -1,3 +1,6 @@
 ANTHROPIC_API_KEY=
 GEMINI_API_KEY=
 OPENAI_API_KEY=
+VERTEX_API_KEY=
+VERTEX_PROJECT=
+VERTEX_LOCATION=us-central1

providertests/builders_test.go

@@ -25,6 +25,7 @@ var languageModelBuilders = []builderPair{
 	{"anthropic-claude-sonnet", builderAnthropicClaudeSonnet4},
 	{"google-gemini-2.5-flash", builderGoogleGemini25Flash},
 	{"google-gemini-2.5-pro", builderGoogleGemini25Pro},
+	{"google-vertex-claude-sonnet", buildVertexClaudeSonnet},
 }
 
 var thinkingLanguageModelBuilders = []builderPair{
@@ -80,3 +81,12 @@ func builderGoogleGemini25Pro(r *recorder.Recorder) (ai.LanguageModel, error) {
 	)
 	return provider.LanguageModel("gemini-2.5-pro")
 }
+
+func buildVertexClaudeSonnet(r *recorder.Recorder) (ai.LanguageModel, error) {
+	provider := google.New(
+		google.WithAPIKey(cmp.Or(os.Getenv("VERTEX_API_KEY"), "(missing)")),
+		google.WithVertex(os.Getenv("VERTEX_PROJECT"), os.Getenv("VERTEX_LOCATION")),
+		google.WithHTTPClient(&http.Client{Transport: r}),
+	)
+	return provider.LanguageModel("claude-3-7-sonnet@20250219")
+}