// A ToolError is a failure the caller can fix: a unit we don't know, a time zone that doesn't// exist, an instant without an offset. The server hands its message back to the model as a tool// result with isError set, so write it as advice: say what was wrong and what would work.// Anything else that throws out of a tool is a bug in this repository.export class ToolError extends Error {  name = "ToolError";}