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Overview

Tool and prompt errors are thrown when a tool or prompt cannot be found or when execution fails. Not-found errors are public and safe to expose to clients, while execution errors are internal and hide implementation details.

Error Reference

ToolNotFoundError

Thrown when a requested tool is not registered in the server.
Example:

ToolExecutionError

Thrown when a tool’s execute() method throws an unexpected error. This is an internal error — the original error details are hidden from clients.
Example:
ToolExecutionError extends InternalMcpError. Clients receive a generic message with an errorId for support correlation, not the original stack trace.

PromptNotFoundError

Thrown when a requested prompt is not registered in the server.
Example:

PromptExecutionError

Thrown when a prompt’s execute() method throws an unexpected error. This is an internal error.
Example: