diff --git a/go/ai/gen.go b/go/ai/gen.go
index 80a9d04e8c..6cebbaa024 100644
--- a/go/ai/gen.go
+++ b/go/ai/gen.go
@@ -60,6 +60,7 @@ const (
 type GenerateResponse struct {
 	Candidates []*Candidate     `json:"candidates,omitempty"`
 	Custom     any              `json:"custom,omitempty"`
+	Request    *GenerateRequest `json:"request,omitempty"`
 	Usage      *GenerationUsage `json:"usage,omitempty"`
 }
 
diff --git a/go/genkit/dotprompt/genkit.go b/go/genkit/dotprompt/genkit.go
index 841c1acdb9..ecdb79b478 100644
--- a/go/genkit/dotprompt/genkit.go
+++ b/go/genkit/dotprompt/genkit.go
@@ -200,10 +200,5 @@ func (p *Prompt) Execute(ctx context.Context, input *ActionInput) (*ai.GenerateR
 		return nil, err
 	}
 
-	// TODO(ianlancetaylor): The TypeScript code stores genReq
-	// with each candidate in resp. The TypeScript code
-	// extends CandidateData with an optional request field.
-	// We don't have a natural way to do that in Go.
-
 	return resp, nil
 }
diff --git a/go/genkit/dotprompt/genkit_test.go b/go/genkit/dotprompt/genkit_test.go
index 190c32e6c2..4fd78a8542 100644
--- a/go/genkit/dotprompt/genkit_test.go
+++ b/go/genkit/dotprompt/genkit_test.go
@@ -39,6 +39,7 @@ func (testGenerator) Generate(ctx context.Context, req *ai.GenerateRequest, cb g
 				},
 			},
 		},
+		Request: req,
 	}
 	return r, nil
 }
diff --git a/go/plugins/googleai/googleai.go b/go/plugins/googleai/googleai.go
index 96109d8683..577c12841f 100644
--- a/go/plugins/googleai/googleai.go
+++ b/go/plugins/googleai/googleai.go
@@ -100,7 +100,9 @@ func (g *generator) Generate(ctx context.Context, input *ai.GenerateRequest, cb
 		if err != nil {
 			return nil, err
 		}
-		return translateResponse(resp), nil
+		r := translateResponse(resp)
+		r.Request = input
+		return r, nil
 	}
 
 	// Streaming version.
@@ -134,6 +136,7 @@ func (g *generator) Generate(ctx context.Context, input *ai.GenerateRequest, cb
 		// to return an empty instead of nil result.
 		r = &ai.GenerateResponse{}
 	}
+	r.Request = input
 	return r, nil
 }
 
diff --git a/go/plugins/vertexai/vertexai.go b/go/plugins/vertexai/vertexai.go
index 301832effc..12155b27f2 100644
--- a/go/plugins/vertexai/vertexai.go
+++ b/go/plugins/vertexai/vertexai.go
@@ -74,7 +74,9 @@ func (g *generator) Generate(ctx context.Context, input *ai.GenerateRequest, cb
 	}
 
 	// Translate from a genai.GenerateContentResponse to a ai.GenerateResponse.
-	r := &ai.GenerateResponse{}
+	r := &ai.GenerateResponse{
+		Request: input,
+	}
 	for _, cand := range resp.Candidates {
 		c := &ai.Candidate{}
 		c.Index = int(cand.Index)