(VB.NET) Streaming AI with Automatic JavaScript AI Tool Function Calling

See more AI Examples

• Tool function implementations are in JavaScript.
• The JavaScript also provides a tool registry and permissions.
• The JavaScript runs embedded within your application using Chilkat.Js.
• Tool calls are handled entirely within Chilkat. Your application does not need to manually check for function calls in the AI response. Internal to the Ask function, Chilkat will handle function calls by calling your registered JavaScript tools and will send results back to the AI model until the final response is received.

Note: This example requires Chilkat v11.4.0 or greater.

For more information, see https://www.chilkatsoft.com/automatic_ai_javascript_tool_function_calling.asp

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

Dim success As Boolean = False

' ----------------------------------------------------------------------------------
' The Javascript file loaded here is shown at the bottom of this page.
' -----------------------------------------------------------------------------------

Dim sbJs As New Chilkat.StringBuilder
success = sbJs.LoadFile("qa_data/js_tools/horoscope_tools.js","utf-8")
If (success = False) Then
    Debug.WriteLine(sbJs.LastErrorText)
    Exit Sub
End If


Dim ai As New Chilkat.Ai

' Register the tools that will be made available to the AI.
Dim evalOnly As Boolean = False
Dim allowAllKeyword As Boolean = True
ai.RegisterJsTools(sbJs,evalOnly,allowAllKeyword)

' The provider can be "openai", "google", "claude", "grok", "mistral", "custom", etc.
ai.Provider = "openai"
' Use your provider's API key.
ai.ApiKey = "MY_API_KEY"
' Choose a model.
ai.Model = "gpt-5-mini"

' Tool function calling must always occur within a conversation.
Dim conversation_name As String = "convo_astrology"
Dim sysMessage As String = "You are a helpful astrologer"
Dim devMessage As String = "Respond only with markdown."
ai.NewConvo(conversation_name,sysMessage,devMessage)

' Provide inputs
ai.InputAddText("What is my horoscope? I am an Aquarius.")

' Get the response in streaming mode.
ai.Streaming = True

' In streaming mode, if we receive an AI event that is a request for tool use,
' we'll need to make the call to the JavaScript and then continue with a followup Ask,
' until the final response is received.

Dim sbEventName As New Chilkat.StringBuilder
Dim sbDelta As New Chilkat.StringBuilder
Dim sbFullResponse As New Chilkat.StringBuilder

' When PollAi returns with an event, it's highly unlikely the
' call to NextAiEvent does not immediately return.  Setting a max
' timeout is just a precaution..
Dim maxWaitMs As Integer = 5000

Dim finished As Boolean = False
Dim numAsks As Integer = 0
' Set a max # of followup Asks to prevent any unexpected infinite looping.
While Not finished And (numAsks < 10)

    ' Send the request to the AI model.
    success = ai.Ask("text")
    If (success = False) Then
        Debug.WriteLine(ai.LastErrorText)
        Exit Sub
    End If


    Dim madeFunctionCalls As Boolean = False
    Dim streamingDone As Boolean = False

    While Not streamingDone
        Dim result As Integer = ai.PollAi(False)
        If (result < 0) Then
            Debug.WriteLine(ai.LastErrorText)
            Debug.WriteLine("Failed.")
            Exit Sub
        End If

        If (result > 0) Then
            ' We have an event..
            success = ai.NextAiEvent(maxWaitMs,sbEventName,sbDelta)
            If (success = False) Then
                Debug.WriteLine(ai.LastErrorText)
                Exit Sub
            End If


            ' Is this an event where the AI is requesting a function call?
            If (sbEventName.ContentsEqual("js_function_call",True)) Then
                ' Call the JavaScript function.
                ' We don't need to find the exact function and make the call.  
                ' We can simply pass the sbDelta (which contains information about the function to be called and the args).
                ' Chilkat will find the registered JavaScript function, call it, and add the results to the conversation.
                ' We indicate that function calls were made, which results in a followup Ask (in the outer loop).
                success = ai.StreamingJsToolCall(sbDelta)
                If (success = False) Then
                    ' The JS function call failed.
                    streamingDone = True
                Else
                    madeFunctionCalls = True
                End If

            Else
                If (Not sbEventName.ContentsEqual("empty",True)) Then
                    sbFullResponse.AppendSb(sbDelta)

                    If (sbEventName.ContentsEqual("null_terminator",True)) Then
                        streamingDone = True
                    End If

                End If

            End If


        Else
            ' No event arrived, so wait a short time rather than spin in a loop..
            ai.SleepMs(100)
        End If


    End While

    If (Not madeFunctionCalls) Then
        finished = True
    End If


    numAsks = numAsks + 1
End While

Debug.WriteLine("Full Response:")
Debug.WriteLine(sbFullResponse.GetAsString())

// The namespace for the AI tool functions in this JavaScript source file.
// You must provide a namespace.
Example = {};

// ----------------------------
// Tool implementation functions
// -----------------------------
// Tool functions must ALWAYS have just a single argument, which is an object.

// The function name used here must match the "name" in the toolRegistry below.

// By grouping get_compatibility, get_horoscope, toolRegistry, and toolPermissions under the Example object, 
// you are "namespacing" them. This tells anyone reading the code (and the JavaScript engine itself) 
// that these tools belong together and prevents them from clashing with another function that might 
// also be named get_horoscope. 

Example.get_compatibility = function(arg) {
  return  `${arg.sign1} is compatible with ${arg.sign2} in a ${arg.relationship_type} way.`;
}

Example.get_horoscope = function(arg) {
  return  `${arg.sign} : Next Tuesday you will befriend a baby otter.`;
}


// -------------
// Tool Registry
// -------------
// The inputSchema.type must ALWAYS be "object".
// Use this format regardless of the AI provider (ChatGPT, Gemini, Claude, Grok, Mistral, etc.)
Example.toolRegistry = [
  {
    name: "get_horoscope",
    description: "Get today's horoscope for an astrological sign.",
    parameters: {
      properties: {
        sign: { type: "string", description: "An astrological sign like Taurus or Aquarius" }
      },
    }
  },
  {
      name: "get_compatibility",
      description: "Returns compatibility analysis between two zodiac signs, including a score and explanation.",
      parameters: {
        properties: {
          sign1: {
            type: "string", description: "The first zodiac sign (e.g., Aries, Taurus, Gemini)."
          },
          sign2: {
            type: "string", description: "The second zodiac sign (e.g., Aries, Taurus, Gemini)."
          },
          relationship_type: {
            type: "string", description: "Type of compatibility to evaluate. (e.g., romantic, friendship, professional, general)"
          },
          detail_level: {
            type: "string", description: "Level of detail in the response. (e.g., short, medium, detailed)"
          }
        }
      }
  }
];

Example.toolPermissions = [
	  {
	    name: "all",
	    perm: "sandbox",
	  }
	  		
	];
	
// Return the name of this toolset
// This tells Chilkat the namespace of this toolset.
"Example";