Avoid decoding full tool results when forking conversations

internal/agents/fork.go

@@ -171,7 +171,7 @@ func (m *Manager) fork(ctx context.Context, src api.Task, project api.Project, n
 	if srcSess.Vendor == api.Antigravity {
 		return api.Task{}, "", fmt.Errorf("%w: snapshot %d of task %s is from an Antigravity session, and agy can't fork a conversation", ErrConflict, n, src.Id)
 	}
-	events, err := m.store.TaskEvents(ctx, src.Id, 0, -1)
+	events, err := m.store.ForkEvents(ctx, src.Id, srcSess.Id)
 	if err != nil {
 		return api.Task{}, "", err
 	}
@@ -217,7 +217,7 @@ func (m *Manager) Continue(ctx context.Context, srcSess api.AgentSession, src ap
 		return m.store.GetTask(ctx, prior.TaskId)
 	}
 
-	events, err := m.store.TaskEvents(ctx, src.Id, 0, -1)
+	events, err := m.store.ForkEvents(ctx, src.Id, srcSess.Id)
 	if err != nil {
 		return api.Task{}, err
 	}

internal/store/store.go

@@ -973,6 +973,22 @@ func (s *Store) TaskEvents(ctx context.Context, taskID string, after int64, limi
 	return scanEvents(rows)
 }
 
+// ForkEvents returns only the payload fields needed to find a safe conversation boundary.
+// Tool results can contain large captures that would otherwise be decoded just to discard them.
+func (s *Store) ForkEvents(ctx context.Context, taskID, sessionID string) ([]api.Event, error) {
+	rows, err := s.db.QueryContext(ctx, `
+		SELECT seq, kind, project_id, task_id, agent_session_id, owner, actor,
+			json_object('vendor_uuid', json_extract(payload, '$.vendor_uuid'),
+				'id', json_extract(payload, '$.id'), 'tool_use_id', json_extract(payload, '$.tool_use_id')),
+			created_at
+		FROM events WHERE task_id = ? AND agent_session_id = ? ORDER BY seq
+	`, taskID, sessionID)
+	if err != nil {
+		return nil, err
+	}
+	return scanEvents(rows)
+}
+
 func (s *Store) TranscriptEvents(ctx context.Context, taskID string, after int64, limit int) ([]api.Event, error) {
 	query := "SELECT " + eventColumns + " FROM events WHERE task_id = ? AND seq > ?"
 	args := []any{taskID, after}