Merge pull request #50 from modelcontextprotocol/justin/call-tool-iserror

`CallToolResult.isError` should not be required

Author: jspahrsummers

package-lock.json

@@ -723,7 +723,7 @@ export const CallToolResultSchema = ResultSchema.extend({
   content: z.array(
     z.union([TextContentSchema, ImageContentSchema, EmbeddedResourceSchema]),
   ),
-  isError: z.boolean().default(false),
+  isError: z.boolean().default(false).optional(),
 });
 
 /**