diff --git a/src/features/tmux-subagent/index.ts b/src/features/tmux-subagent/index.ts
index 254edac93..e900555fb 100644
--- a/src/features/tmux-subagent/index.ts
+++ b/src/features/tmux-subagent/index.ts
@@ -10,6 +10,7 @@ export * from "./session-status-parser"
 export * from "./session-message-count"
 export * from "./session-ready-waiter"
 export * from "./types"
+export * from "./pane-state-parser"
 export * from "./pane-state-querier"
 export * from "./decision-engine"
 export * from "./action-executor"
diff --git a/src/features/tmux-subagent/pane-state-querier.ts b/src/features/tmux-subagent/pane-state-querier.ts
index 005e31672..e2ac9bfd1 100644
--- a/src/features/tmux-subagent/pane-state-querier.ts
+++ b/src/features/tmux-subagent/pane-state-querier.ts
@@ -29,7 +29,12 @@ export async function queryWindowState(sourcePaneId: string): Promise<WindowStat
   }
 
   const parsedPaneState = parsePaneStateOutput(stdout)
-  if (!parsedPaneState) return null
+  if (!parsedPaneState) {
+    log("[pane-state-querier] failed to parse pane state output", {
+      sourcePaneId,
+    })
+    return null
+  }
 
   const { panes } = parsedPaneState
   const windowWidth = parsedPaneState.windowWidth