diff --git a/internal/converter/gnostic/convertions.go b/internal/converter/gnostic/convertions.go
index 6b558e3..f067c13 100644
--- a/internal/converter/gnostic/convertions.go
+++ b/internal/converter/gnostic/convertions.go
@@ -360,13 +360,16 @@ func toMediaTypes(items *goa3.MediaTypes) *orderedmap.Map[string, *v3.MediaType]
 	}
 	content := orderedmap.New[string, *v3.MediaType]()
 	for _, item := range items.GetAdditionalProperties() {
-		content.Set(item.Name, &v3.MediaType{
+		mt := &v3.MediaType{
 			Schema:     toSchemaOrReference(item.Value.Schema),
-			Example:    item.Value.Example.ToRawInfo(),
 			Examples:   toExamples(item.Value.GetExamples()),
 			Encoding:   toEncodings(item.Value.GetEncoding()),
 			Extensions: toExtensions(item.Value.GetSpecificationExtension()),
-		})
+		}
+		if val := item.GetValue().Example; val != nil {
+			mt.Example = val.ToRawInfo()
+		}
+		content.Set(item.Name, mt)
 	}
 	return content
 }
@@ -403,7 +406,11 @@ func toHeaders(v *goa3.HeadersOrReferences) *orderedmap.Map[string, *v3.Header]
 func toCodes(responses []*goa3.NamedResponseOrReference) *orderedmap.Map[string, *v3.Response] {
 	resps := orderedmap.New[string, *v3.Response]()
 	for _, resp := range responses {
-		resps.Set(resp.Name, toResponse(resp.Value.GetResponse()))
+		switch tt := resp.GetValue().Oneof.(type) {
+		case *goa3.ResponseOrReference_Reference:
+		case *goa3.ResponseOrReference_Response:
+			resps.Set(resp.Name, toResponse(tt.Response))
+		}
 	}
 	return resps
 }
diff --git a/internal/converter/gnostic/paths.go b/internal/converter/gnostic/paths.go
index b922003..6b55bbc 100644
--- a/internal/converter/gnostic/paths.go
+++ b/internal/converter/gnostic/paths.go
@@ -34,7 +34,16 @@ func PathItemWithMethodAnnotations(item *v3.PathItem, md protoreflect.MethodDesc
 		}
 
 		if opts.Responses != nil {
-			oper.Responses = toResponses(opts.Responses)
+			responses := toResponses(opts.Responses)
+			for pair := responses.Codes.First(); pair != nil; pair = pair.Next() {
+				oper.Responses.Codes.Set(pair.Key(), pair.Value())
+			}
+			if responses.Default != nil {
+				oper.Responses.Default = responses.Default
+			}
+			for pair := responses.Extensions.First(); pair != nil; pair = pair.Next() {
+				oper.Responses.Extensions.Set(pair.Key(), pair.Value())
+			}
 		}
 
 		if opts.Callbacks != nil {
diff --git a/internal/converter/testdata/fileset.binpb b/internal/converter/testdata/fileset.binpb
index 14124e0..faa69c2 100644
Binary files a/internal/converter/testdata/fileset.binpb and b/internal/converter/testdata/fileset.binpb differ
diff --git a/internal/converter/testdata/standard/gnostic.proto b/internal/converter/testdata/standard/gnostic.proto
index e2f172e..178e61e 100644
--- a/internal/converter/testdata/standard/gnostic.proto
+++ b/internal/converter/testdata/standard/gnostic.proto
@@ -42,6 +42,26 @@ service Greeter {
   rpc SayHello(HelloRequest) returns (HelloReply) {
     option idempotency_level = NO_SIDE_EFFECTS;
     option (gnostic.openapi.v3.operation) = {
+      responses: {
+        response_or_reference: {
+          name: "404"
+          value: {
+            response: {
+              description: "user is not found"
+              content: {
+                additional_properties: {
+                  name: "application/json"
+                  value: {
+                    schema: {
+                      reference: {_ref: "#/components/schemas/connect.error"}
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
       deprecated: true
       security: [
         {
diff --git a/internal/converter/testdata/standard/output/gnostic.openapi.json b/internal/converter/testdata/standard/output/gnostic.openapi.json
index 8003fa8..a4e5526 100644
--- a/internal/converter/testdata/standard/output/gnostic.openapi.json
+++ b/internal/converter/testdata/standard/output/gnostic.openapi.json
@@ -115,6 +115,16 @@
                 }
               }
             }
+          },
+          "404": {
+            "description": "user is not found",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/connect.error"
+                }
+              }
+            }
           }
         },
         "deprecated": true,
@@ -178,6 +188,16 @@
                 }
               }
             }
+          },
+          "404": {
+            "description": "user is not found",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/connect.error"
+                }
+              }
+            }
           }
         },
         "deprecated": true,
diff --git a/internal/converter/testdata/standard/output/gnostic.openapi.yaml b/internal/converter/testdata/standard/output/gnostic.openapi.yaml
index 317eff2..4f8ea16 100644
--- a/internal/converter/testdata/standard/output/gnostic.openapi.yaml
+++ b/internal/converter/testdata/standard/output/gnostic.openapi.yaml
@@ -71,6 +71,12 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/example_with_gnostic.HelloReply'
+        "404":
+          description: user is not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/connect.error'
       deprecated: true
       security:
         - BasicAuth: []
@@ -109,6 +115,12 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/example_with_gnostic.HelloReply'
+        "404":
+          description: user is not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/connect.error'
       deprecated: true
       security:
         - BasicAuth: []