.Net: Bug: Kernel.Invoke Function is not calling other functions specified in the prompt template

[vamsidogiparthi]

Describe the bug
Currently, I have been trying to invoke some functions from registered plugins (registered using DI) in the Handlebar yaml prompt template. But the kernel is not invoking the function and returning a message saying cannot find the current user time.

Program.cs

using IAUI.Agent.Plugins.FunctionPlugin;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
// Learn more about configuring OpenAPI at https://aka.ms/aspnet/openapi

var configuration = new ConfigurationBuilder()
    .SetBasePath(Directory.GetCurrentDirectory())
    .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
    .AddUserSecrets<Program>(optional: true)
    .AddEnvironmentVariables()
    .Build();

builder.Services.AddOpenApi();
builder.Services.AddLogging(loggingBuilder =>
    loggingBuilder.AddConsole().AddConfiguration(configuration.GetSection("Logging"))
);
builder.Services.AddOptions();
builder.Services.Configure<OpenAIConfiguration>(
    configuration.GetSection(OpenAIConfiguration.SectionName)
);
builder.Services.Configure<IAUIStoreDatabaseConfiguration>(
    configuration.GetSection(IAUIStoreDatabaseConfiguration.SectionName)
);

builder.Services.Configure<GoogleAIConfiguration>(
    configuration.GetSection(GoogleAIConfiguration.SectionName)
);

builder.Services.Configure<ProfileScoringAlgorithmConfiguration>(
    configuration.GetSection(ProfileScoringAlgorithmConfiguration.SectionName)
);

builder.Services.AddSingleton<IIAUIDatabaseService, IAUIDatabaseService>();
builder.Services.AddSingleton<IDataSeeder, DataSeeder>();
builder.Services.AddSingleton<IProfileScoringService, ProfileScoringService>();

builder.Services.AddSingleton<IChatCompletionService>(sp =>
{
    var openAIConfiguration =
        configuration.GetSection(OpenAIConfiguration.SectionName).Get<OpenAIConfiguration>()
        ?? throw new Exception("OpenAI configuration is missing");

    var googleAIConfiguration =
        configuration.GetSection(GoogleAIConfiguration.SectionName).Get<GoogleAIConfiguration>()
        ?? throw new Exception("Google AI configuration is missing");

#pragma warning disable SKEXP0070 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
    // return new GoogleAIGeminiChatCompletionService(
    //     googleAIConfiguration.Model,
    //     googleAIConfiguration.ApiKey
    // );
#pragma warning restore SKEXP0070 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.

    return new OpenAIChatCompletionService(openAIConfiguration.Model, openAIConfiguration.ApiKey);
});

builder.Services.AddTransient<TimePlugin>();

//builder.Services.AddSingleton<ProfileDataFetchPlugin>();
builder.Services.AddKeyedTransient<ProfileScoringPlugin>(nameof(ProfileScoringPlugin));

builder.Services.AddTransient<UIComponentLibraryPlugin>();
builder.Services.AddKeyedTransient(
    "IAUIKKernel",
    (sp, key) =>
    {
        KernelPluginCollection kernelFunctions = [];
        kernelFunctions.AddFromObject(sp.GetRequiredService<TimePlugin>());
        //kernelFunctions.AddFromObject(sp.GetRequiredService<ProfileDataFetchPlugin>());
        kernelFunctions.AddFromObject(
            sp.GetRequiredKeyedService<ProfileScoringPlugin>(nameof(ProfileScoringPlugin))
        );
        kernelFunctions.AddFromObject(sp.GetRequiredService<UIComponentLibraryPlugin>());

        return new Kernel(sp, kernelFunctions);
    }
);

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
}

app.UseHttpsRedirection();

//await app.Services.GetRequiredService<IDataSeeder>().SeedData();
await app.Services.GetRequiredService<IProfileScoringService>().GetUIComponentLibrariesAsync();

Yaml Prompt Template:

name: PromptTemplateTest
template: |
  <message role="system">
  The current time is {{TimePlugin.get_time}}
  </message>
template_format: handlebars
description: This is a test template to check the functionality of the PromptTemplate.
input_variables:
  - name: user
    description: user profile information.
    is_required: true
    allow_dangerously_set_content: false
output_variable:
  description: The output will be in json format. It will contain the userId, profileScore, uiComponents, theme, languageCode and localizationLanguageCode.

TimePlugin:

namespace IAUI.Agent.Plugins.FunctionPlugin;

using System.ComponentModel;

public class TimePlugin()
{
    [KernelFunction("get_time")]
    [Description("Get the current time.")]
    public string GetTime()
    {
        return DateTime.Now.ToString("HH:mm:ss");
    }

    [KernelFunction("get_date")]
    [Description("Get the current date.")]
    public string GetDate()
    {
        return DateTime.Now.ToString("yyyy-MM-dd");
    }

    [KernelFunction("get_date_with_format")]
    [Description("Get the current date with requested fornmat")]
    public string GetDate(
        [Description(
            "contains the desired date time format in which the output date time should be"
        )]
            string format
    )
    {
        return DateTime.Now.ToString(format);
    }

    [KernelFunction("get_time_and_date")]
    [Description("Get the current time and date.")]
    public string GetTimeAndDate()
    {
        return DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
    }

    [KernelFunction("get_time_and_date_with_format")]
    [Description("Get the current time and date with requested format.")]
    public string GetTimeAndDate(
        [Description("Desired format in which the current datetime has to be converted to")]
            string format
    )
    {
        return DateTime.Now.ToString(format);
    }

    [KernelFunction("get_local_time_zone")]
    [Description("Get the local time zone.")]
    public string GetLocalTimeZone()
    {
        return TimeZoneInfo.Local.DisplayName;
    }

    [KernelFunction("get_local_time_zone_iana")]
    [Description("Get the local time zone in IANA format.")]
    public string GetLocalTimeZoneIana()
    {
        return TimeZoneInfo.Local.Id;
    }

    [KernelFunction("convert_to_desired_time_zone")]
    [Description("Convert the given time to the desired time zone.")]
    public string ConvertToDesiredTimeZone(
        [Description("date time to be converted")] string time,
        [Description("source datetime time zone")] string sourceTimeZone,
        [Description("desired datetime time zone to which the conversion should happen")]
            string destinationTimeZone
    )
    {
        DateTime dateTime = DateTime.Parse(time);
        TimeZoneInfo sourceTZ = TimeZoneInfo.FindSystemTimeZoneById(sourceTimeZone);
        TimeZoneInfo destinationTZ = TimeZoneInfo.FindSystemTimeZoneById(destinationTimeZone);

        dateTime = TimeZoneInfo.ConvertTime(dateTime, sourceTZ, destinationTZ);
        return dateTime.ToString("yyyy-MM-dd HH:mm:ss");
    }

    [KernelFunction("get_time_in_time_zone")]
    [Description("Get the current time in the given time zone.")]
    public string GetCurrentTimeInTimeZone(
        [Description("Desired timezone in which we want the current time to be")] string timeZone
    )
    {
        DateTime dateTime = DateTime.UtcNow;
        TimeZoneInfo timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(timeZone);
        dateTime = TimeZoneInfo.ConvertTimeFromUtc(dateTime, timeZoneInfo);
        return dateTime.ToString("HH:mm:ss");
    }

    [KernelFunction("get_current_date_time_in_time_zone")]
    [Description("Get the current time in the given time zone.")]
    public string GetCurrentDateTimeInTimeZone(
        [Description("Desired timezone in which we want the current datetime to be")]
            string timeZone
    )
    {
        DateTime dateTime = DateTime.UtcNow;
        TimeZoneInfo timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(timeZone);
        dateTime = TimeZoneInfo.ConvertTimeFromUtc(dateTime, timeZoneInfo);
        return dateTime.ToString("yyyy-MM-dd HH:mm:ss");
    }

    [KernelFunction("Get_Date_Time_In_Date_Time_Offset")]
    [Description("Get the Date time offset for the given Date Time.")]
    public DateTimeOffset GetDateTimeInDateTimeOffset(
        [Description("date time to be converted to date time offset")] string dateTime
    )
    {
        return DateTimeOffset.Parse(dateTime);
    }
}

Expected behavior:

The LLM should call the function as instructed to get the current use time during the kernel invocation

Platform

• Language: [C#]
• Source:

   <PackageReference Include="Microsoft.SemanticKernel" Version="1.48.0" />
   <PackageReference Include="Microsoft.SemanticKernel.Connectors.Google" Version="1.49.0-alpha" />
   <PackageReference Include="Microsoft.SemanticKernel.PromptTemplates.Handlebars" Version="1.48.0" />
   <PackageReference Include="Microsoft.SemanticKernel.Yaml" Version="1.48.0" />

• AI model: [gpt-4o, gpt-4.1-mini, gpt-4.1, gpt-4o-mini]
• IDE: [ VS Code]
• OS: Mac]

Additional context:

my github repo

[rogeriorfp]

Describe the bug Currently, I have been trying to invoke some functions from registered plugins (registered using DI) in the Handlebar yaml prompt template. But the kernel is not invoking the function and returning a message saying cannot find the current user time.

Program.cs

using IAUI.Agent.Plugins.FunctionPlugin;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
// Learn more about configuring OpenAPI at https://aka.ms/aspnet/openapi

var configuration = new ConfigurationBuilder()
.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
.AddUserSecrets(optional: true)
.AddEnvironmentVariables()
.Build();

builder.Services.AddOpenApi();
builder.Services.AddLogging(loggingBuilder =>
loggingBuilder.AddConsole().AddConfiguration(configuration.GetSection("Logging"))
);
builder.Services.AddOptions();
builder.Services.Configure(
configuration.GetSection(OpenAIConfiguration.SectionName)
);
builder.Services.Configure(
configuration.GetSection(IAUIStoreDatabaseConfiguration.SectionName)
);

builder.Services.Configure(
configuration.GetSection(GoogleAIConfiguration.SectionName)
);

builder.Services.Configure(
configuration.GetSection(ProfileScoringAlgorithmConfiguration.SectionName)
);

builder.Services.AddSingleton<IIAUIDatabaseService, IAUIDatabaseService>();
builder.Services.AddSingleton<IDataSeeder, DataSeeder>();
builder.Services.AddSingleton<IProfileScoringService, ProfileScoringService>();

builder.Services.AddSingleton(sp =>
{
var openAIConfiguration =
configuration.GetSection(OpenAIConfiguration.SectionName).Get()
?? throw new Exception("OpenAI configuration is missing");

var googleAIConfiguration =
    configuration.GetSection(GoogleAIConfiguration.SectionName).Get<GoogleAIConfiguration>()
    ?? throw new Exception("Google AI configuration is missing");

#pragma warning disable SKEXP0070 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
// return new GoogleAIGeminiChatCompletionService(
// googleAIConfiguration.Model,
// googleAIConfiguration.ApiKey
// );
#pragma warning restore SKEXP0070 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.

return new OpenAIChatCompletionService(openAIConfiguration.Model, openAIConfiguration.ApiKey);

});

builder.Services.AddTransient();

//builder.Services.AddSingleton();
builder.Services.AddKeyedTransient(nameof(ProfileScoringPlugin));

builder.Services.AddTransient();
builder.Services.AddKeyedTransient(
"IAUIKKernel",
(sp, key) =>
{
KernelPluginCollection kernelFunctions = [];
kernelFunctions.AddFromObject(sp.GetRequiredService());
//kernelFunctions.AddFromObject(sp.GetRequiredService());
kernelFunctions.AddFromObject(
sp.GetRequiredKeyedService(nameof(ProfileScoringPlugin))
);
kernelFunctions.AddFromObject(sp.GetRequiredService());

    return new Kernel(sp, kernelFunctions);
}

);

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.MapOpenApi();
}

app.UseHttpsRedirection();

//await app.Services.GetRequiredService().SeedData();
await app.Services.GetRequiredService().GetUIComponentLibrariesAsync();

Yaml Prompt Template:

name: PromptTemplateTest
template: |

The current time is {{TimePlugin.get_time}}

template_format: handlebars
description: This is a test template to check the functionality of the PromptTemplate.
input_variables:

• name: user
  description: user profile information.
  is_required: true
  allow_dangerously_set_content: false
  output_variable:
  description: The output will be in json format. It will contain the userId, profileScore, uiComponents, theme, languageCode and localizationLanguageCode.

Expected behavior:

The LLM should call the function as instructed to get the current use time during the kernel invocation

Platform

• Language: [C#]
• Source:
  
  
  
  
• AI model: [gpt-4o, gpt-4.1-mini, gpt-4.1, gpt-4o-mini]
• IDE: [ VS Code]
• OS: Mac]

Additional context:

my github repo

Hi @vamsidogiparthi , the correct name of the function that returns the current time is TimePlugin.Time

[vamsidogiparthi]

Hi @rogeriorfp,
Below is the TimePlugin code. Sorry my bad. I named the function with get_time. Hope this helps.

namespace IAUI.Agent.Plugins.FunctionPlugin;

using System.ComponentModel;

public class TimePlugin()
{
    [KernelFunction("get_time")]
    [Description("Get the current time.")]
    public string GetTime()
    {
        return DateTime.Now.ToString("HH:mm:ss");
    }

    [KernelFunction("get_date")]
    [Description("Get the current date.")]
    public string GetDate()
    {
        return DateTime.Now.ToString("yyyy-MM-dd");
    }

    [KernelFunction("get_date_with_format")]
    [Description("Get the current date with requested fornmat")]
    public string GetDate(
        [Description(
            "contains the desired date time format in which the output date time should be"
        )]
            string format
    )
    {
        return DateTime.Now.ToString(format);
    }

    [KernelFunction("get_time_and_date")]
    [Description("Get the current time and date.")]
    public string GetTimeAndDate()
    {
        return DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
    }

    [KernelFunction("get_time_and_date_with_format")]
    [Description("Get the current time and date with requested format.")]
    public string GetTimeAndDate(
        [Description("Desired format in which the current datetime has to be converted to")]
            string format
    )
    {
        return DateTime.Now.ToString(format);
    }

    [KernelFunction("get_local_time_zone")]
    [Description("Get the local time zone.")]
    public string GetLocalTimeZone()
    {
        return TimeZoneInfo.Local.DisplayName;
    }

    [KernelFunction("get_local_time_zone_iana")]
    [Description("Get the local time zone in IANA format.")]
    public string GetLocalTimeZoneIana()
    {
        return TimeZoneInfo.Local.Id;
    }

    [KernelFunction("convert_to_desired_time_zone")]
    [Description("Convert the given time to the desired time zone.")]
    public string ConvertToDesiredTimeZone(
        [Description("date time to be converted")] string time,
        [Description("source datetime time zone")] string sourceTimeZone,
        [Description("desired datetime time zone to which the conversion should happen")]
            string destinationTimeZone
    )
    {
        DateTime dateTime = DateTime.Parse(time);
        TimeZoneInfo sourceTZ = TimeZoneInfo.FindSystemTimeZoneById(sourceTimeZone);
        TimeZoneInfo destinationTZ = TimeZoneInfo.FindSystemTimeZoneById(destinationTimeZone);

        dateTime = TimeZoneInfo.ConvertTime(dateTime, sourceTZ, destinationTZ);
        return dateTime.ToString("yyyy-MM-dd HH:mm:ss");
    }

    [KernelFunction("get_time_in_time_zone")]
    [Description("Get the current time in the given time zone.")]
    public string GetCurrentTimeInTimeZone(
        [Description("Desired timezone in which we want the current time to be")] string timeZone
    )
    {
        DateTime dateTime = DateTime.UtcNow;
        TimeZoneInfo timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(timeZone);
        dateTime = TimeZoneInfo.ConvertTimeFromUtc(dateTime, timeZoneInfo);
        return dateTime.ToString("HH:mm:ss");
    }

    [KernelFunction("get_current_date_time_in_time_zone")]
    [Description("Get the current time in the given time zone.")]
    public string GetCurrentDateTimeInTimeZone(
        [Description("Desired timezone in which we want the current datetime to be")]
            string timeZone
    )
    {
        DateTime dateTime = DateTime.UtcNow;
        TimeZoneInfo timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(timeZone);
        dateTime = TimeZoneInfo.ConvertTimeFromUtc(dateTime, timeZoneInfo);
        return dateTime.ToString("yyyy-MM-dd HH:mm:ss");
    }

    [KernelFunction("Get_Date_Time_In_Date_Time_Offset")]
    [Description("Get the Date time offset for the given Date Time.")]
    public DateTimeOffset GetDateTimeInDateTimeOffset(
        [Description("date time to be converted to date time offset")] string dateTime
    )
    {
        return DateTimeOffset.Parse(dateTime);
    }
}

[rogeriorfp]

Sorry, I didn't notice you were using a customized version.

@vamsidogiparthi, change the call to TimePlugin-get_time by replacing the dot (.) with a dash (-).

[vamsidogiparthi]

Hi @rogeriorfp ,
Thanks for the update. I tried it and seemed like with handlebar prompt template format. It has to use (-) instead of (.) it worked.