diff --git a/afk/agents/base.py b/afk/agents/base.py
index 0839caa..564ac1c 100644
--- a/afk/agents/base.py
+++ b/afk/agents/base.py
@@ -508,8 +508,19 @@ def respond(self, user_message: str) -> Iterator[StreamChunk]:
             had_post_end = False
             call_seen = False
             rollback_len = len(self.history)
+            start_injected = False
+            if not in_thought and not content:
+                self.history.append({"role": "assistant", "content": START_TAG})
+                start_injected = True
             try:
                 for c in self.stream(content):
+                    if start_injected:
+                        yield {"status": "start_thinking", "thinking": True}
+                        in_thought = True
+                        start_injected = False
+                        if c.get("status") == "start_thinking":
+                            in_thought = True
+                            continue
                     orig_thinking = c.get("thinking", orig_thinking)
                     if c.get("status") == "start_thinking":
                         in_thought = True