fix(acp): replay interrupted prompts for steer

acp_adapter/server.py

@@ -569,6 +569,9 @@ class HermesACPAgent(acp.Agent):
     async def cancel(self, session_id: str, **kwargs: Any) -> None:
         state = self.session_manager.get_session(session_id)
         if state and state.cancel_event:
+            with state.runtime_lock:
+                if state.is_running and state.current_prompt_text:
+                    state.interrupted_prompt_text = state.current_prompt_text
             state.cancel_event.set()
             try:
                 if getattr(state, "agent", None) and hasattr(state.agent, "interrupt"):
@@ -666,6 +669,25 @@ class HermesACPAgent(acp.Agent):
         if not has_content:
             return PromptResponse(stop_reason="end_turn")
 
+        # Zed currently interrupts an active ACP request before delivering a
+        # follow-up slash command. If that follow-up is /steer, there may be no
+        # live AIAgent left to steer by the time this method runs. Salvage that
+        # UX by replaying the interrupted prompt with the steer text attached as
+        # explicit correction/guidance.
+        if isinstance(user_content, str) and user_text.startswith("/steer"):
+            steer_text = user_text.split(maxsplit=1)[1].strip() if len(user_text.split(maxsplit=1)) > 1 else ""
+            interrupted_prompt = ""
+            with state.runtime_lock:
+                if not state.is_running and steer_text and state.interrupted_prompt_text:
+                    interrupted_prompt = state.interrupted_prompt_text
+                    state.interrupted_prompt_text = ""
+            if interrupted_prompt:
+                user_text = (
+                    f"{interrupted_prompt}\n\n"
+                    f"User correction/guidance after interrupt: {steer_text}"
+                )
+                user_content = user_text
+
         # Intercept slash commands — handle locally without calling the LLM.
         # Slash commands are text-only; if the client included images/resources,
         # send the whole multimodal prompt to the agent instead of treating it as
@@ -694,6 +716,7 @@ class HermesACPAgent(acp.Agent):
                     await self._conn.session_update(session_id, update)
                 return PromptResponse(stop_reason="end_turn")
             state.is_running = True
+            state.current_prompt_text = user_text or "[Image attachment]"
 
         logger.info("Prompt on session %s: %s", session_id, user_text[:100])
 
@@ -808,6 +831,7 @@ class HermesACPAgent(acp.Agent):
             logger.exception("Executor error for session %s", session_id)
             with state.runtime_lock:
                 state.is_running = False
+                state.current_prompt_text = ""
             return PromptResponse(stop_reason="end_turn")
 
         if result.get("messages"):
@@ -838,6 +862,7 @@ class HermesACPAgent(acp.Agent):
         # normal follow-up user prompts, preserving role alternation and history.
         with state.runtime_lock:
             state.is_running = False
+            state.current_prompt_text = ""
 
         while True:
             with state.runtime_lock:

acp_adapter/session.py

@@ -148,6 +148,8 @@ class SessionState:
     is_running: bool = False
     queued_prompts: List[str] = field(default_factory=list)
     runtime_lock: Any = field(default_factory=Lock)
+    current_prompt_text: str = ""
+    interrupted_prompt_text: str = ""
 
 
 class SessionManager: