diff --git a/src/execution.ts b/src/execution.ts
index 44e5710..d68f7c0 100644
--- a/src/execution.ts
+++ b/src/execution.ts
@@ -246,7 +246,7 @@ async function executeFromQueue(channel: string) {
         ...config.chatCompletionParams,
         messages: OpenAImessages,
         // FIXME: don't use new instance of FunctionManager
-        functions: new FunctionManager().getFunctionsForOpenAi(),
+        tools: new FunctionManager().getToolsForOpenAi(),
       });
 
       logUsedTokens(answer, message, ++functionRanCounter);
@@ -254,13 +254,11 @@ async function executeFromQueue(channel: string) {
       generatedMessage = answer.choices[0].message;
       if (!generatedMessage) throw new Error("Empty message received");
 
-      // handle function calls
-      if (generatedMessage.function_call) {
+      // handle tool calls
+      if (generatedMessage.tool_calls !== undefined && generatedMessage.tool_calls.length > 0) {
         OpenAImessages.push(generatedMessage);
         // FIXME: don't use new instance of FunctionManager
-        OpenAImessages.push(
-          new FunctionManager().handleFunction(generatedMessage.function_call)
-        );
+        OpenAImessages.push(...(await new FunctionManager().handleToolCalls(generatedMessage.tool_calls)));
       }
     } while (generatedMessage.function_call);
 
diff --git a/src/funcitonManager.ts b/src/funcitonManager.ts
index 11b1bac..6ab27d0 100644
--- a/src/funcitonManager.ts
+++ b/src/funcitonManager.ts
@@ -1,4 +1,9 @@
-import { ChatCompletionCreateParams, ChatCompletionMessage, ChatCompletionMessageParam } from "openai/resources/chat";
+import { FunctionDefinition } from "openai/resources";
+import {
+  ChatCompletionMessageParam
+, ChatCompletionMessageToolCall
+, ChatCompletionTool
+} from "openai/resources/chat";
 
 type parameterMap = {
   string: string,
@@ -11,8 +16,10 @@ type OpenAIFunctionRequestData<T extends nameTypeMap> = {
   [name in keyof T]: T[name];
 };
 
-type ChatCompletionFunctions = ChatCompletionCreateParams.Function;
-type ChatCompletionFunctionCall = ChatCompletionMessage.FunctionCall;
+type ChatCompletionToolDefinition = ChatCompletionTool;
+type ChatCompletionToolCall = ChatCompletionMessageToolCall;
+
+type ChatCompletionFunctionDefinition = FunctionDefinition;
 
 /**
  * Represents the function that can be ran by the OpenAI model
@@ -33,7 +40,7 @@ export interface OpenAIFunction<T extends nameTypeMap = nameTypeMap> {
 }
 
 export abstract class OpenAIFunction<T extends nameTypeMap = nameTypeMap> {
-  getSettings(): ChatCompletionFunctions {
+  getSettings(): ChatCompletionFunctionDefinition {
     return {
       name: this.name,
       description: this.description,
@@ -41,7 +48,7 @@ export abstract class OpenAIFunction<T extends nameTypeMap = nameTypeMap> {
     };
   }
 
-  abstract execute(data: OpenAIFunctionRequestData<T>): string;
+  abstract execute(data: OpenAIFunctionRequestData<T>): Promise<string>;
 }
 
 /*
@@ -54,47 +61,67 @@ export default class FunctionManager {
     // TODO: import functions from functions directory
   }
 
-  public getFunctions(): ChatCompletionFunctions[] {
-    const rvalue: ChatCompletionFunctions[] = [];
+  public getTools(): ChatCompletionToolDefinition[] {
+    const rvalue: ChatCompletionToolDefinition[] = [];
     for (const [, value] of this.store) {
-      rvalue.push(value.getSettings());
+      rvalue.push({type: "function", function: value.getSettings()});
     }
     return rvalue;
   }
 
-  public getFunctionsForOpenAi(): ChatCompletionFunctions[] | undefined {
-    const rvalue = this.getFunctions();
+  public getToolsForOpenAi(): ChatCompletionTool[] | undefined {
+    const rvalue = this.getTools();
     return rvalue.length > 0 ? rvalue : undefined;
   }
 
-  public handleFunction(request: ChatCompletionFunctionCall): ChatCompletionMessageParam {
+  public handleFunction(request: ChatCompletionToolCall): Promise<ChatCompletionMessageParam> {
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     let parsedArguments: any;
     
-    const functionToRun = this.store.get(request.name ?? "");
+    const functionToRun = this.store.get(request.function.name);
 
     // check if the function is registered
     if (!functionToRun) {
-      return {
+      return Promise.resolve({
         role: "system",
-        content: "Only use functions that were provided to you",
-      };
+        content: `Only use functions that were provided to you (response for tool call ID: ${request.id})`,
+      });
     }
 
     try {
       // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
-      parsedArguments = JSON.parse(request.arguments ?? "");
+      parsedArguments = JSON.parse(request.function.arguments);
     }
     catch (e) {
-      console.error("Function arguments raw: " + request.arguments);
-      throw new Error(`Failed to parse the function JSON arguments when running function [${request.name}]`, {cause: e});
+      console.error("Function arguments raw: " + request.function.arguments);
+      throw new Error(`Failed to parse the function JSON arguments when running function [${request.function.name}]`, {cause: e});
     }
     // FIXME: Verify if the parsedArguments matches the requested function argument declaration.
-    return {
-      role: "function",
-      name: request.name,
-      // eslint-disable-next-line @typescript-eslint/no-unsafe-argument
-      content: functionToRun.execute(parsedArguments),
-    };
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-argument
+    return functionToRun.execute(parsedArguments).then(content => {
+      return {
+        role: "tool",
+        tool_call_id: request.id,
+        content: content,
+      };
+    });
+  }
+
+  public handleToolCall(call: ChatCompletionToolCall): Promise<ChatCompletionMessageParam> {
+    if (call.type === "function") {
+      return this.handleFunction(call);
+    }
+    // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
+    throw new Error(`Unsupported tool call type: ${call.type || "never"}`);
+  }
+
+  public handleToolCalls(calls: ChatCompletionToolCall[]) {
+    const rvalue: Promise<ChatCompletionMessageParam>[] = [];
+    for (const call of calls) {
+      if (call.type === "function") {
+        rvalue.push(this.handleToolCall(call));
+      }
+    }
+    return Promise.all(rvalue);
   }
 }