Exceptions
| Exception | Meaning |
|---|---|
MCPError | Base public MCP failure. |
ProtocolError | Invalid or failed MCP protocol exchange. |
TransportError | Process, stream, or HTTP transport failure. |
OperationTimeout | Configured deadline elapsed. |
OperationCancelled | Caller or owning runtime cancelled the work. |
CleanupError | Resource cleanup failed. |
KitClosed | Work was requested after the kit closed. |
SessionBusy | Concurrent work conflicts with the session state. |
SessionStillOpen | A finalized result was requested before session closure. |
TraceNotFinalized | Final trace data was requested too early. |
TraceUnavailable | The execution has no usable trace. |
RawEvidenceUnavailable | Required raw evidence was not captured or retained. |
RawEvidenceIntegrityError | Stored raw evidence failed integrity checks. |
ExecutionNotFound | Requested execution identity is absent. |
InvalidTransitionError | Execution state transition is invalid. |
ModelValidationError | Public input or result model failed validation. |
UnsupportedFeature | The selected integration does not support the operation. |
ElicitationExpectationError | An input request did not satisfy its plan. |
ElicitationRoundLimitError | The supported interaction round limit was exceeded. |
Normal MCP tool errors usually remain typed tool results rather than raised exceptions. Test result.is_error when the server intentionally returned a tool-level failure.