GitLab API: Create Job and run in runner

I would like to trigger new job for runner but I get bed request. How to do it correctly?

From C# code → I would like to create job will go to runner and execute → without choose project/branch/create new job but api go to runner

public async Task<string> TriggerCommandOnRunner(int runnerId, string command)
    {
        try
        {
            // Create a new job to run the specified command on the GitLab Runner.
            var jobRequest = new
            {
                job = new
                {
                    runner_id = runnerId,
                    script = command
                }
            };

            var content = new StringContent(JsonSerializer.Serialize(jobRequest), Encoding.UTF8,
                "application/json");
            var response = await _httpClient.PostAsync($"{_gitLabUrl}jobs/request", content);

            if (response.IsSuccessStatusCode)
            {
                var responseBody = await response.Content.ReadAsStringAsync();
                // Parse and process the responseBody as needed.
                return responseBody;
            }

            return await Task.FromResult("failed with connection");
        }
        catch (Exception ex)
        {
            return await Task.FromResult($"failed {ex.Message}");
        }

        return string.Empty;
    }