fix: eval tool_call_response uses correct event field names

SessionFromEvents and buildTranscript were looking for a non-existent
"tool_call" nested map in tool_call_response events. The actual
ToolCallResponseEvent serializes with "tool_call_id" (top-level string)
and "tool_definition" (top-level object), so the type assertions always
failed silently — tool call results were never written to sessions and
transcript tool names were empty.

Fix both functions to use the correct field names and update tests to
match the real ToolCallResponseEvent JSON format.

Assisted-By: docker-agent

Author: hamza-jeddad

pkg/evaluation/eval.go

@@ -575,7 +575,10 @@ 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".
+			td, _ := event["tool_definition"].(map[string]any)
+			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"},
 	}