The MCP specification defines the cursor parameter as an optional string. In the world of TypeScript, an optional string is either string or undefined. It does not include null values.

Currently, the Client.ListTools function allows for null values to be sent to the server, which is not aligned with the specifications and therefore does not play well with some MCP servers.

I propose we update the code as in #124

References:

• Optional parameters in TypeScript: https://www.typescriptlang.org/docs/handbook/2/functions.html#optional-parameters
• MCP official definition: https://github.com/modelcontextprotocol/modelcontextprotocol/blob/ec1418927730e3ffeede8ea6475d6f4c36f6d10c/schema/draft/schema.ts#L368