fix: persist ResultMessage errors to session and simplify adapter

- Append COPILOT_ERROR_PREFIX marker when convert_message produces a
  StreamError, so the error card survives page refresh.
- Collapse duplicate ternaries into a single if/else block.

autogpt_platform/backend/backend/copilot/sdk/response_adapter.py

@@ -216,15 +216,11 @@ class SDKResponseAdapter:
                 responses.append(StreamFinish())
             elif sdk_message.subtype in ("error", "error_during_execution"):
                 raw_error = str(sdk_message.result or "Unknown error")
-                is_transient = is_transient_api_error(raw_error)
-                responses.append(
-                    StreamError(
-                        errorText=(
-                            FRIENDLY_TRANSIENT_MSG if is_transient else raw_error
-                        ),
-                        code=("transient_api_error" if is_transient else "sdk_error"),
-                    )
-                )
+                if is_transient_api_error(raw_error):
+                    error_text, code = FRIENDLY_TRANSIENT_MSG, "transient_api_error"
+                else:
+                    error_text, code = raw_error, "sdk_error"
+                responses.append(StreamError(errorText=error_text, code=code))
                 responses.append(StreamFinish())
             else:
                 logger.warning(

autogpt_platform/backend/backend/copilot/sdk/service.py

@@ -1218,7 +1218,7 @@ async def stream_chat_completion_sdk(
                                 extra,
                             )
 
-                        # Log errors being sent to frontend
+                        # Persist error markers so they survive page refresh
                         if isinstance(response, StreamError):
                             logger.error(
                                 "%s Sending error to frontend: %s (code=%s)",
@@ -1226,6 +1226,13 @@ async def stream_chat_completion_sdk(
                                 response.errorText,
                                 response.code,
                             )
+                            session.messages.append(
+                                ChatMessage(
+                                    role="assistant",
+                                    content=f"{COPILOT_ERROR_PREFIX} {response.errorText}",
+                                )
+                            )
+                            ended_with_stream_error = True
 
                         yield response