"""Litestar MCP exceptions."""
__all__ = ("BridgeConnectionError", "BridgeMessageTooLargeError", "LitestarMCPError", "MissingDependencyError")
class LitestarMCPError(Exception):
"""Base exception for Litestar MCP."""
class BridgeConnectionError(LitestarMCPError):
"""Raised when the stdio bridge cannot connect to its target endpoint."""
def __init__(self, endpoint: str) -> None:
super().__init__(
f"Could not connect to Litestar MCP endpoint at {endpoint}. "
"Make sure the Litestar app is running and reachable, or pass --base-url/--endpoint with the correct URL.",
)
class BridgeMessageTooLargeError(LitestarMCPError, ValueError):
"""Raised when a stdio JSON-RPC frame exceeds the bridge line limit."""
def __init__(self, max_bytes: int) -> None:
super().__init__(f"Stdio JSON-RPC message exceeded the bridge limit of {max_bytes} bytes.")
[docs]
class MissingDependencyError(LitestarMCPError, ImportError):
"""Missing optional dependency.
This exception is raised when a module depends on a dependency that has not
been installed.
Args:
package: Name of the missing package.
install_package: Optional alternative package name to install directly.
extra: Optional project extra that installs the missing package.
"""
[docs]
def __init__(self, package: str, install_package: str | None = None, *, extra: str | None = None) -> None:
install_package = install_package or package
extra = extra or install_package
super().__init__(
f"Package {package!r} is not installed but required. You can install it by running "
f"'pip install litestar-mcp[{extra}]' to install litestar-mcp with the required extra "
f"or 'pip install {install_package}' to install the package separately",
)
