Add ensure_valid_tool_response: outbound pre-flight normalizer for circuit breaker prevention

agent.py

@@ -1407,6 +1407,8 @@ def _clear_responses_pending_state(self) -> None:
 
     @extension.extensible
     async def process_tools(self, msg: str):
+        # Pre-flight: normalize any non-tool-call output before the framework sees it
+        msg = extract_tools.ensure_valid_tool_response(msg)
         # search for tool usage requests in agent message
         tool_request = extract_tools.json_parse_dirty(msg)
 

helpers/extract_tools.py

@@ -163,3 +163,35 @@ def replace_unescaped_newlines(match):
         r'(?<=: ")(.*?)(?=")', replace_unescaped_newlines, json_string, flags=re.DOTALL
     )
     return fixed_string
+
+
+def ensure_valid_tool_response(raw_response: str) -> str:
+    """
+    Pre-flight checker: if the agent's own output isn't a valid tool-call
+    envelope, normalize it into one BEFORE the framework sees it.
+
+    Priority ladder:
+    1. Already valid {"tool_name":..., "tool_args":{...}} -> pass through
+    2. Has a parseable json_root with tool_name but missing args  -> wrap in response()
+    3. Completely non-JSON (plain prose) -> wrap entire output as response().text
+    4. Empty/null -> return valid empty response()
+    """
+    import json
+    if not raw_response or not isinstance(raw_response, str):
+        return json.dumps({"tool_name": "response", "tool_args": {"text": ""}})
+
+    stripped = raw_response.strip()
+
+    # Case 1: Already valid tool-call envelope
+    if stripped.startswith('{'):
+        parsed = json_parse_dirty(stripped)
+        if parsed and _is_tool_request(parsed):
+            return stripped  # pass through - safe
+        # Case 2: It's JSON but not a tool call - wrap in response()
+        if parsed and isinstance(parsed, dict):
+            content = json.dumps(parsed, ensure_ascii=False)
+            return json.dumps({"tool_name": "response", "tool_args": {"text": content}})
+
+    # Case 3: Not valid JSON at all - wrap entire output as response() text
+    safe_text = stripped.replace('\\', '\\\\').replace('"', '\\"')[:32000]
+    return json.dumps({"tool_name": "response", "tool_args": {"text": safe_text}})