docs: add Google-style docstrings to errors.py

utils/errors.py

@@ -2,18 +2,38 @@
 
 
 class AgentError(Exception):
+    """Custom exception for errors that happen inside the agent.
+
+    Attributes:
+        message: The error message.
+        details: Extra info about what went wrong.
+        cause: The exception that caused this, if any.
+    """
+
     def __init__(
         self,
         message: str,
         details: dict[str, Any] | None = None,
         cause: Exception | None = None,
     ) -> None:
+        """Sets up the error with a message and optional extra context.
+
+        Args:
+            message: A short description of what went wrong.
+            details: Optional dict with more info about the error.
+            cause: The original exception that led to this one, if any.
+        """
         super().__init__(message)
         self.message = message
         self.details = details or {}
         self.cause = cause
 
     def __str__(self) -> str:
+        """Builds a readable string from the error info.
+
+        Returns:
+            The error message, with details and cause included if present.
+        """
         base = self.message
         if self.details:
             detail_str = ", ".join(f"{k}={v}" for k, v in self.details.items())
@@ -23,6 +43,11 @@ def __str__(self) -> str:
         return base
 
     def to_dict(self) -> dict[str, Any]:
+        """Turns the error into a plain dictionary.
+
+        Returns:
+            A dict with the error type, message, details, and cause.
+        """
         return {
             "type": self.__class__.__name__,
             "message": self.message,
@@ -32,13 +57,28 @@ def to_dict(self) -> dict[str, Any]:
 
 
 class ConfigError(AgentError):
+    """Raised when something goes wrong with the configuration.
+
+    Attributes:
+        config_key: The config key that caused the issue.
+        config_file: The config file where the problem was found.
+    """
+
     def __init__(
         self,
         message: str,
         config_key: str | None = None,
         config_file: str | None = None,
         **kwargs: Any,
     ) -> None:
+        """Sets up the config error with relevant file/key info.
+
+        Args:
+            message: Description of the config problem.
+            config_key: The key in the config that caused the error.
+            config_file: Path to the config file with the issue.
+            **kwargs: Any extra args passed up to AgentError.
+        """
         details = kwargs.pop("details", {}) or {}
         if config_key:
             details["config_key"] = config_key