chore: import upstream snapshot with attribution

browser_use/llm/exceptions.py

@@ -0,0 +1,43 @@
+class ModelError(Exception):
+	pass
+
+
+class ModelProviderError(ModelError):
+	"""Exception raised when a model provider returns an error."""
+
+	def __init__(
+		self,
+		message: str,
+		status_code: int = 502,
+		model: str | None = None,
+	):
+		super().__init__(message)
+		self.message = message
+		self.status_code = status_code
+		self.model = model
+
+
+class ModelRateLimitError(ModelProviderError):
+	"""Exception raised when a model provider returns a rate limit error."""
+
+	def __init__(
+		self,
+		message: str,
+		status_code: int = 429,
+		model: str | None = None,
+	):
+		super().__init__(message, status_code, model)
+
+
+class ModelOutputTruncatedError(ModelProviderError):
+	"""Output was cut off at an output-token limit (finish_reason='length' / stop_reason='max_tokens').
+
+	Status 400 keeps it out of same-provider retry loops; the agent's fallback switch treats it as recoverable.
+	"""
+
+	def __init__(
+		self,
+		message: str,
+		model: str | None = None,
+	):
+		super().__init__(message, status_code=400, model=model)