diff --git a/go/ai/embedder.go b/go/ai/embedder.go
index 5126898c2..622b05581 100644
--- a/go/ai/embedder.go
+++ b/go/ai/embedder.go
@@ -36,5 +36,5 @@ type EmbedRequest struct {
 // RegisterEmbedder registers the actions for a specific embedder.
 func RegisterEmbedder(name string, embedder Embedder) {
 	genkit.RegisterAction(genkit.ActionTypeEmbedder, name,
-		genkit.NewAction(name, embedder.Embed))
+		genkit.NewAction(name, nil, embedder.Embed))
 }
diff --git a/go/ai/generator.go b/go/ai/generator.go
index 745ff2663..8833cd009 100644
--- a/go/ai/generator.go
+++ b/go/ai/generator.go
@@ -33,10 +33,39 @@ type Generator interface {
 	Generate(context.Context, *GenerateRequest, genkit.StreamingCallback[*Candidate]) (*GenerateResponse, error)
 }
 
+// GeneratorCapabilities describes various capabilities of the generator.
+type GeneratorCapabilities struct {
+	Multiturn  bool
+	Media      bool
+	Tools      bool
+	SystemRole bool
+}
+
+// GeneratorMetadata is the metadata of the generator, specifying things like nice user visible label, capabilities, etc.
+type GeneratorMetadata struct {
+	Label    string
+	Supports GeneratorCapabilities
+}
+
 // RegisterGenerator registers the generator in the global registry.
-func RegisterGenerator(name string, generator Generator) {
-	genkit.RegisterAction(genkit.ActionTypeModel, name,
-		genkit.NewStreamingAction(name, generator.Generate))
+func RegisterGenerator(provider, name string, metadata *GeneratorMetadata, generator Generator) {
+	metadataMap := map[string]any{}
+	if metadata != nil {
+		if metadata.Label != "" {
+			metadataMap["label"] = metadata.Label
+		}
+		supports := map[string]bool{
+			"media":      metadata.Supports.Media,
+			"multiturn":  metadata.Supports.Multiturn,
+			"systemRole": metadata.Supports.SystemRole,
+			"tools":      metadata.Supports.Tools,
+		}
+		metadataMap["supports"] = supports
+	}
+	genkit.RegisterAction(genkit.ActionTypeModel, provider,
+		genkit.NewStreamingAction(name, map[string]any{
+			"model": metadataMap,
+		}, generator.Generate))
 }
 
 // generatorActionType is the instantiated genkit.Action type registered
diff --git a/go/ai/retriever.go b/go/ai/retriever.go
index b47558c22..9bb1fc029 100644
--- a/go/ai/retriever.go
+++ b/go/ai/retriever.go
@@ -52,10 +52,10 @@ type RetrieverResponse struct {
 // RegisterRetriever registers the actions for a specific retriever.
 func RegisterRetriever(name string, retriever Retriever) {
 	genkit.RegisterAction(genkit.ActionTypeRetriever, name,
-		genkit.NewAction(name, retriever.Retrieve))
+		genkit.NewAction(name, nil, retriever.Retrieve))
 
 	genkit.RegisterAction(genkit.ActionTypeIndexer, name,
-		genkit.NewAction(name, func(ctx context.Context, req *IndexerRequest) (struct{}, error) {
+		genkit.NewAction(name, nil, func(ctx context.Context, req *IndexerRequest) (struct{}, error) {
 			err := retriever.Index(ctx, req)
 			return struct{}{}, err
 		}))
diff --git a/go/genkit/action.go b/go/genkit/action.go
index 556902ebb..e05220792 100644
--- a/go/genkit/action.go
+++ b/go/genkit/action.go
@@ -65,14 +65,14 @@ type Action[I, O, S any] struct {
 // See js/common/src/types.ts
 
 // NewAction creates a new Action with the given name and non-streaming function.
-func NewAction[I, O any](name string, fn func(context.Context, I) (O, error)) *Action[I, O, struct{}] {
-	return NewStreamingAction(name, func(ctx context.Context, in I, cb NoStream) (O, error) {
+func NewAction[I, O any](name string, metadata map[string]any, fn func(context.Context, I) (O, error)) *Action[I, O, struct{}] {
+	return NewStreamingAction(name, metadata, func(ctx context.Context, in I, cb NoStream) (O, error) {
 		return fn(ctx, in)
 	})
 }
 
 // NewStreamingAction creates a new Action with the given name and streaming function.
-func NewStreamingAction[I, O, S any](name string, fn Func[I, O, S]) *Action[I, O, S] {
+func NewStreamingAction[I, O, S any](name string, metadata map[string]any, fn Func[I, O, S]) *Action[I, O, S] {
 	var i I
 	var o O
 	return &Action[I, O, S]{
@@ -80,6 +80,7 @@ func NewStreamingAction[I, O, S any](name string, fn Func[I, O, S]) *Action[I, O
 		fn:           fn,
 		inputSchema:  inferJSONSchema(i),
 		outputSchema: inferJSONSchema(o),
+		Metadata:     metadata,
 	}
 }
 
diff --git a/go/genkit/action_test.go b/go/genkit/action_test.go
index 7b074e8a4..82c638b54 100644
--- a/go/genkit/action_test.go
+++ b/go/genkit/action_test.go
@@ -26,7 +26,7 @@ func inc(_ context.Context, x int) (int, error) {
 }
 
 func TestActionRun(t *testing.T) {
-	a := NewAction("inc", inc)
+	a := NewAction("inc", nil, inc)
 	got, err := a.Run(context.Background(), 3, nil)
 	if err != nil {
 		t.Fatal(err)
@@ -37,7 +37,7 @@ func TestActionRun(t *testing.T) {
 }
 
 func TestActionRunJSON(t *testing.T) {
-	a := NewAction("inc", inc)
+	a := NewAction("inc", nil, inc)
 	input := []byte("3")
 	want := []byte("4")
 	got, err := a.runJSON(context.Background(), input, nil)
@@ -63,7 +63,7 @@ func count(ctx context.Context, n int, cb StreamingCallback[int]) (int, error) {
 
 func TestActionStreaming(t *testing.T) {
 	ctx := context.Background()
-	a := NewStreamingAction("count", count)
+	a := NewStreamingAction("count", nil, count)
 	const n = 3
 
 	// Non-streaming.
diff --git a/go/genkit/dev_server_test.go b/go/genkit/dev_server_test.go
index a6ad7ea6b..679f39cb5 100644
--- a/go/genkit/dev_server_test.go
+++ b/go/genkit/dev_server_test.go
@@ -37,8 +37,12 @@ func TestDevServer(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	r.registerAction("test", "devServer", NewAction("inc", inc))
-	r.registerAction("test", "devServer", NewAction("dec", dec))
+	r.registerAction("test", "devServer", NewAction("inc", map[string]any{
+		"foo": "bar",
+	}, inc))
+	r.registerAction("test", "devServer", NewAction("dec", map[string]any{
+		"bar": "baz",
+	}, dec))
 	srv := httptest.NewServer(newDevServerMux(r))
 	defer srv.Close()
 
@@ -78,10 +82,9 @@ func TestDevServer(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		md := map[string]any{"inputSchema": nil, "outputSchema": nil}
 		want := map[string]actionDesc{
-			"/test/devServer/dec": {Key: "/test/devServer/dec", Name: "dec", Metadata: md},
-			"/test/devServer/inc": {Key: "/test/devServer/inc", Name: "inc", Metadata: md},
+			"/test/devServer/inc": {Key: "/test/devServer/inc", Name: "inc", Metadata: map[string]any{"inputSchema": nil, "outputSchema": nil, "foo": "bar"}},
+			"/test/devServer/dec": {Key: "/test/devServer/dec", Name: "dec", Metadata: map[string]any{"inputSchema": nil, "outputSchema": nil, "bar": "baz"}},
 		}
 		if !maps.EqualFunc(got, want, actionDesc.equal) {
 			t.Errorf("\n got  %v\nwant %v", got, want)
diff --git a/go/genkit/dotprompt/genkit.go b/go/genkit/dotprompt/genkit.go
index ee5a7ad8c..a44cf2c25 100644
--- a/go/genkit/dotprompt/genkit.go
+++ b/go/genkit/dotprompt/genkit.go
@@ -134,9 +134,9 @@ func (p *Prompt) Action() (*genkit.Action[*ActionInput, *ai.GenerateResponse, st
 		name += "." + p.Variant
 	}
 
-	a := genkit.NewAction(name, p.Execute)
+	a := genkit.NewAction(name, nil, p.Execute)
 	a.Metadata = map[string]any{
-		"type": "prompt",
+		"type":   "prompt",
 		"prompt": p,
 	}
 	return a, nil
diff --git a/go/genkit/flow.go b/go/genkit/flow.go
index a4993492e..0dcab4b78 100644
--- a/go/genkit/flow.go
+++ b/go/genkit/flow.go
@@ -227,7 +227,7 @@ type FlowResult[O any] struct {
 
 // action creates an action for the flow. See the comment at the top of this file for more information.
 func (f *Flow[I, O, S]) action() *Action[*flowInstruction[I], *flowState[I, O], S] {
-	return NewStreamingAction(f.name, func(ctx context.Context, inst *flowInstruction[I], cb StreamingCallback[S]) (*flowState[I, O], error) {
+	return NewStreamingAction(f.name, nil, func(ctx context.Context, inst *flowInstruction[I], cb StreamingCallback[S]) (*flowState[I, O], error) {
 		spanMetaKey.fromContext(ctx).SetAttr("flow:wrapperAction", "true")
 		return f.runInstruction(ctx, inst, cb)
 	})
diff --git a/go/genkit/tracing_test.go b/go/genkit/tracing_test.go
index 52bdf272b..b3f117871 100644
--- a/go/genkit/tracing_test.go
+++ b/go/genkit/tracing_test.go
@@ -56,7 +56,7 @@ func TestSpanMetadata(t *testing.T) {
 func TestTracing(t *testing.T) {
 	ctx := context.Background()
 	const actionName = "TestTracing-inc"
-	a := NewAction(actionName, inc)
+	a := NewAction(actionName, nil, inc)
 	if _, err := a.Run(context.Background(), 3, nil); err != nil {
 		t.Fatal(err)
 	}
diff --git a/go/plugins/googleai/googleai.go b/go/plugins/googleai/googleai.go
index fcb826a2d..96109d868 100644
--- a/go/plugins/googleai/googleai.go
+++ b/go/plugins/googleai/googleai.go
@@ -204,12 +204,16 @@ func Init(ctx context.Context, model, apiKey string) error {
 		return err
 	}
 	ai.RegisterEmbedder("google-genai", e)
-
 	g, err := NewGenerator(ctx, model, apiKey)
 	if err != nil {
 		return err
 	}
-	ai.RegisterGenerator("google-genai", g)
+	ai.RegisterGenerator("google-genai", model, &ai.GeneratorMetadata{
+		Label: "Google AI - " + model,
+		Supports: ai.GeneratorCapabilities{
+			Multiturn: true,
+		},
+	}, g)
 
 	return nil
 }
diff --git a/go/plugins/vertexai/vertexai.go b/go/plugins/vertexai/vertexai.go
index 8dd053d82..301832eff 100644
--- a/go/plugins/vertexai/vertexai.go
+++ b/go/plugins/vertexai/vertexai.go
@@ -133,7 +133,12 @@ func Init(ctx context.Context, model, projectID, location string) error {
 	if err != nil {
 		return err
 	}
-	ai.RegisterGenerator("google-vertexai", g)
+	ai.RegisterGenerator("google-vertexai", model, &ai.GeneratorMetadata{
+		Label: "Vertex AI - " + model,
+		Supports: ai.GeneratorCapabilities{
+			Multiturn: true,
+		},
+	}, g)
 
 	return nil
 }
diff --git a/go/samples/coffee-shop/main.go b/go/samples/coffee-shop/main.go
index 87d3a2d88..f17186a47 100644
--- a/go/samples/coffee-shop/main.go
+++ b/go/samples/coffee-shop/main.go
@@ -66,9 +66,9 @@ type customerTimeAndHistoryInput struct {
 }
 
 type testAllCoffeeFlowsOutput struct {
-	Pass    bool   `json:"pass"`
+	Pass    bool     `json:"pass"`
 	Replies []string `json:"replies,omitempty"`
-	Error   string `json:"error,omitempty"`
+	Error   string   `json:"error,omitempty"`
 }
 
 func main() {
@@ -79,13 +79,13 @@ func main() {
 		os.Exit(1)
 	}
 
-	if err := googleai.Init(context.Background(), "gemini-pro", apiKey); err != nil {
+	if err := googleai.Init(context.Background(), "gemini-1.0-pro", apiKey); err != nil {
 		log.Fatal(err)
 	}
 
 	simpleGreetingPrompt, err := dotprompt.Define("simpleGreeting",
 		&dotprompt.Frontmatter{
-			Name: "simpleGreeting",
+			Name:  "simpleGreeting",
 			Model: "google-genai",
 			Input: dotprompt.FrontmatterInput{
 				Schema: jsonschema.Reflect(simpleGreetingInput{}),
@@ -106,7 +106,7 @@ func main() {
 		if err != nil {
 			return "", err
 		}
-		ai := &dotprompt.ActionInput{ Variables: vars }
+		ai := &dotprompt.ActionInput{Variables: vars}
 		resp, err := simpleGreetingPrompt.Execute(ctx, ai)
 		if err != nil {
 			return "", err
@@ -120,7 +120,7 @@ func main() {
 
 	greetingWithHistoryPrompt, err := dotprompt.Define("greetingWithHistory",
 		&dotprompt.Frontmatter{
-			Name: "greetingWithHistory",
+			Name:  "greetingWithHistory",
 			Model: "google-genai",
 			Input: dotprompt.FrontmatterInput{
 				Schema: jsonschema.Reflect(customerTimeAndHistoryInput{}),
@@ -141,7 +141,7 @@ func main() {
 		if err != nil {
 			return "", err
 		}
-		ai := &dotprompt.ActionInput{ Variables: vars }
+		ai := &dotprompt.ActionInput{Variables: vars}
 		resp, err := greetingWithHistoryPrompt.Execute(ctx, ai)
 		if err != nil {
 			return "", err
@@ -177,7 +177,7 @@ func main() {
 			return out, nil
 		}
 		out := &testAllCoffeeFlowsOutput{
-			Pass:    true,
+			Pass: true,
 			Replies: []string{
 				test1,
 				test2,