fix: eval tool_call_response uses correct event field names

pkg/evaluation/eval.go

@@ -575,7 +575,12 @@ func buildTranscript(events []map[string]any) string {
 			fmt.Fprintf(&transcript, "[Agent %s calls tool %q with arguments: %s]\n\n", cmp.Or(currentAgent, "unknown"), name, args)
 
 		case "tool_call_response":
-			name, _ := getToolCallInfo(event)
+			// The ToolCallResponseEvent has tool_definition at the top level, not
+			// nested under "tool_call".
+			var name string
+			if td, ok := event["tool_definition"].(map[string]any); ok {
+				name, _ = td["name"].(string)
+			}
 			response, _ := event["response"].(string)
 			if len(response) > 500 {
 				response = response[:500] + "...(truncated)"

pkg/evaluation/eval_test.go

@@ -796,12 +796,11 @@ func TestBuildTranscript(t *testing.T) {
 					},
 				},
 				{
-					"type":     "tool_call_response",
-					"response": "file contents here",
-					"tool_call": map[string]any{
-						"function": map[string]any{
-							"name": "read_file",
-						},
+					"type":         "tool_call_response",
+					"response":     "file contents here",
+					"tool_call_id": "call_123",
+					"tool_definition": map[string]any{
+						"name": "read_file",
 					},
 				},
 			},
@@ -814,12 +813,11 @@ func TestBuildTranscript(t *testing.T) {
 			name: "long tool response truncated",
 			events: []map[string]any{
 				{
-					"type":     "tool_call_response",
-					"response": strings.Repeat("x", 600),
-					"tool_call": map[string]any{
-						"function": map[string]any{
-							"name": "shell",
-						},
+					"type":         "tool_call_response",
+					"response":     strings.Repeat("x", 600),
+					"tool_call_id": "call_789",
+					"tool_definition": map[string]any{
+						"name": "shell",
 					},
 				},
 			},

pkg/evaluation/save.go

@@ -192,21 +192,20 @@ func SessionFromEvents(events []map[string]any, title string, questions []string
 			// Flush any pending assistant message before adding tool response
 			flushAssistantMessage()
 
-			// Add tool response message
-			if tc, ok := event["tool_call"].(map[string]any); ok {
-				toolCallID, _ := tc["id"].(string)
-				response, _ := event["response"].(string)
+			// The ToolCallResponseEvent serializes tool_call_id as a top-level string field,
+			// not nested under a "tool_call" map.
+			toolCallID, _ := event["tool_call_id"].(string)
+			response, _ := event["response"].(string)
 
-				msg := &session.Message{
-					Message: chat.Message{
-						Role:       chat.MessageRoleTool,
-						Content:    response,
-						ToolCallID: toolCallID,
-						CreatedAt:  eventTimestamp,
-					},
-				}
-				sess.AddMessage(msg)
+			msg := &session.Message{
+				Message: chat.Message{
+					Role:       chat.MessageRoleTool,
+					Content:    response,
+					ToolCallID: toolCallID,
+					CreatedAt:  eventTimestamp,
+				},
 			}
+			sess.AddMessage(msg)
 
 		case "token_usage":
 			// Update session token usage

pkg/evaluation/save_test.go

@@ -302,11 +302,9 @@ func TestSessionFromEvents(t *testing.T) {
 					},
 				},
 				{
-					"type": "tool_call_response",
-					"tool_call": map[string]any{
-						"id": "call_123",
-					},
-					"response": "file content",
+					"type":         "tool_call_response",
+					"tool_call_id": "call_123",
+					"response":     "file content",
 				},
 				{"type": "agent_choice", "content": "Done!"},
 				{"type": "stream_stopped"},
@@ -452,11 +450,9 @@ func TestSessionFromEventsWithToolDefinitions(t *testing.T) {
 			},
 		},
 		{
-			"type": "tool_call_response",
-			"tool_call": map[string]any{
-				"id": "call_123",
-			},
-			"response": "file content",
+			"type":         "tool_call_response",
+			"tool_call_id": "call_123",
+			"response":     "file content",
 		},
 		{"type": "stream_stopped"},
 	}