Proposal: jsonrpc: expose Error (fka WireError) #452
Description
Some MCP handlers may need to return jsonrpc errors (for example, if arguments are invalid). Currently, if an error wraps a jsonrpc2.WireError, it is promoted to a jsonrpc2 error by the connection, with the associated error code.
We should expose this type in the SDK API. I think 'WireError' is too much, and therefore suggest:
// An Error represents a JSON-RPC level error.
//
// If JSON-RPC handlers return an Error, it will be used as the wire-level error object.
// https://www.jsonrpc.org/specification#error_object
type Error struct {
// Code is an error code indicating the type of failure.
Code int64 `json:"code"`
// Message is a short description of the error.
Message string `json:"message"`
// Data is optional structured data containing additional information about the error.
Data json.RawMessage `json:"data,omitempty"`
}
func (err *Error) Error() string {
return err.Message
}
func (err *Error) Is(other error) bool {
w, ok := other.(*Error)
if !ok {
return false
}
return err.Code == w.Code
}