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MCP interactions involve network communication, subprocess management, and protocol negotiation. Definable provides specific exception types for each failure mode so you can handle errors precisely.

Error Hierarchy

All MCP errors inherit from MCPError:

Handling Connection Errors

Handling Tool Errors

Handling Server Not Found

Automatic Reconnection

By default, MCP connections automatically reconnect on failure:
Reconnection uses exponential backoff. If all attempts fail, an MCPConnectionError is raised.

Timeout Configuration

Set timeouts at the server level:

Graceful Degradation

When using multiple MCP servers, handle failures for individual servers:

Protocol Errors

Protocol errors indicate a bug in the MCP server or an incompatible protocol version:
If you encounter MCPProtocolError consistently, check that the MCP server is using a compatible version of the protocol and that the transport type matches the server’s expectations.