Can't access variables from AppSync to Lambda.

I'm trying to configure next setup: AppSync using lambda as a resolver for all queries and mutations. I have a problem with appsync resolver template ctx.info.variables. I can't understand what I have overlooked. Everything is looks pretty straightforward but variables in lambda is empty. In Lambda It looks like this in event object:

...
  variables: {},
...

Here is the simple schema:

input CreateSessionInput {
	title: String!
}

type Session {
	id: ID!
	title: String!
}

type Mutation {
	createSession(input: CreateSessionInput!): Session!
}

type Query {
	getAllSessions: [Session!]!
}

I'm using default template of resolver. Here is resolver template:

import { util } from '@aws-appsync/utils';

/**
 * Sends a request to a Lambda function. Passes all information about the request from the `info` object.
 * @param {import('@aws-appsync/utils').Context} ctx the context
 * @returns {import('@aws-appsync/utils').LambdaRequest} the request
 */
export function request(ctx) {
    return {
        operation: 'Invoke',
        payload: {
            fieldName: ctx.info.fieldName,
            parentTypeName: ctx.info.parentTypeName,
            variables: ctx.info.variables,
            selectionSetList: ctx.info.selectionSetList,
            selectionSetGraphQL: ctx.info.selectionSetGraphQL,
        },
    };
}

/**
 * Process a Lambda function response
 * @param {import('@aws-appsync/utils').Context} ctx the context
 * @returns {*} the Lambda function response
 */
export function response(ctx) {
    const { result, error } = ctx;
    if (error) {
        util.error(error.message, error.type, result);
    }
    return result;
}

Here is how I'm trying to access lambda variables.

...
export const handler = async (event) => {
  
  console.log("Variables", event.variables);
...

Here is the log from lambda from event object. Variables is just empty.

2024-03-31T18:56:13.558Z	f481da1e-ba6d-4bc8-a06c-02460c6c731a	INFO	Start event {
  fieldName: 'createSession',
  parentTypeName: 'Mutation',
  variables: {},
  selectionSetList: [ 'id' ],
  selectionSetGraphQL: '{\n  id\n}'
}

In this log variables is just empty object.
May thanks in advance for any ideas or how to deal with this issue.