diff --git a/src/ai_client.py b/src/ai_client.py
index 21dfbc3..fd0b7a4 100644
--- a/src/ai_client.py
+++ b/src/ai_client.py
@@ -51,6 +51,25 @@ events: EventEmitter = EventEmitter()
 
 _ai_proxy = None
 
+class ProviderError(Exception):
+ def __init__(self, kind: str, provider: str, original: Exception) -> None:
+  self.kind = kind
+  self.provider = provider
+  self.original = original
+  super().__init__(str(original))
+
+ def ui_message(self) -> str:
+  labels = {
+   "quota":      "QUOTA EXHAUSTED",
+   "rate_limit": "RATE LIMITED",
+   "auth":       "AUTH / API KEY ERROR",
+   "balance":    "BALANCE / BILLING ERROR",
+   "network":    "NETWORK / CONNECTION ERROR",
+   "unknown":    "API ERROR",
+  }
+  label = labels.get(self.kind, "API ERROR")
+  return f"[{self.provider.upper()} {label}]\n\n{self.original}"
+
 def _get_proxy():
     global _ai_proxy
     if _ai_proxy is None and os.environ.get("AI_SERVER_ENABLED"):
@@ -298,31 +317,6 @@ def _load_credentials() -> dict[str, Any]:
    f"Or set SLOP_CREDENTIALS env var to a custom path."
   )
 
-class ProviderError(Exception):
- def __init__(self, kind: str, provider: str, original: Exception) -> None:
-  """
-  [C: src/api_hooks.py:HookServerInstance.__init__, src/mcp_client.py:_DDGParser.__init__, src/mcp_client.py:_TextExtractor.__init__]
-  """
-  self.kind = kind
-  self.provider = provider
-  self.original = original
-  super().__init__(str(original))
-
- def ui_message(self) -> str:
-  """
-  [C: src/app_controller.py:AppController._handle_request_event, src/app_controller.py:AppController.generate]
-  """
-  labels = {
-   "quota":      "QUOTA EXHAUSTED",
-   "rate_limit": "RATE LIMITED",
-   "auth":       "AUTH / API KEY ERROR",
-   "balance":    "BALANCE / BILLING ERROR",
-   "network":    "NETWORK / CONNECTION ERROR",
-   "unknown":    "API ERROR",
-  }
-  label = labels.get(self.kind, "API ERROR")
-  return f"[{self.provider.upper()} {label}]\n\n{self.original}"
-
 def _classify_anthropic_error(exc: Exception) -> ProviderError:
  try:
   if isinstance(exc, anthropic.RateLimitError):