diff --git a/src/games/storywriter/components/chat-sidebar.tsx b/src/games/storywriter/components/chat-sidebar.tsx
index 54835fe..0eed2c0 100644
--- a/src/games/storywriter/components/chat-sidebar.tsx
+++ b/src/games/storywriter/components/chat-sidebar.tsx
@@ -1,7 +1,7 @@
 import { Sidebar } from "./sidebar";
-import { useAppState } from "../contexts/state";
+import { useAppState, type ChatMessage } from "../contexts/state";
 import styles from '../assets/chat-sidebar.module.css';
-import { useState, useRef, useEffect } from "preact/hooks";
+import { useState, useRef, useEffect, useMemo, useCallback } from "preact/hooks";
 import LLM from "../utils/llm";
 import { highlight } from "../utils/highlight";
 import Prompt from "../utils/prompt";
@@ -14,7 +14,7 @@ export const ChatSidebar = () => {
     const [isLoading, setIsLoading] = useState(false);
     const [error, setError] = useState<string | null>(null);
     const messagesRef = useRef<HTMLDivElement>(null);
-    const abortControllerRef = useRef<AbortController | null>(null);
+    const abortControllerRef = useRef<AbortController>(new AbortController());
 
     useEffect(() => {
         if (messagesRef.current) {
@@ -31,20 +31,16 @@ export const ChatSidebar = () => {
         };
     }, []);
 
-    const sendMessage = async () => {
-        if (!currentStory || !input.trim() || !connection || !model || isLoading) return;
+    const sendMessage = useCallback(async (newMessages: ChatMessage[]) => {
+        if (!currentStory || !connection || !model) return;
 
-        const userMessage = {
-            id: crypto.randomUUID(),
-            role: 'user' as const,
-            content: input.trim(),
-        };
-
-        dispatch({
-            type: 'ADD_CHAT_MESSAGE',
-            storyId: currentStory.id,
-            message: userMessage,
-        });
+        for (const message of newMessages) {
+            dispatch({
+                type: 'ADD_CHAT_MESSAGE',
+                storyId: currentStory.id,
+                message,
+            });
+        }
 
         const assistantMessageId = crypto.randomUUID();
         dispatch({
@@ -57,11 +53,7 @@ export const ChatSidebar = () => {
             },
         });
 
-        setInput('');
-        setIsLoading(true);
-        setError(null);
-
-        const request = Prompt.compilePrompt(appState, userMessage);
+        const request = Prompt.compilePrompt(appState, newMessages);
 
         if (!request) {
             setError('Failed to compile prompt');
@@ -71,11 +63,18 @@ export const ChatSidebar = () => {
 
         try {
             let accumulatedContent = '';
+            let tool_calls: LLM.ToolCall[] | undefined;
 
             for await (const chunk of LLM.generateStream(connection, request)) {
-                const delta = chunk.choices[0]?.delta?.content;
-                if (delta) {
-                    accumulatedContent += delta;
+                const delta = chunk.choices[0]?.delta;
+
+                if (delta?.tool_calls) {
+                    tool_calls = delta.tool_calls;
+                }
+
+                const content = delta?.content;
+                if (content) {
+                    accumulatedContent += content;
                     dispatch({
                         type: 'ADD_CHAT_MESSAGE',
                         storyId: currentStory.id,
@@ -83,6 +82,7 @@ export const ChatSidebar = () => {
                             id: assistantMessageId,
                             role: 'assistant',
                             content: accumulatedContent,
+                            tool_calls,
                         },
                     });
                 }
@@ -90,22 +90,73 @@ export const ChatSidebar = () => {
                     break;
                 }
             }
+            const assistantMessage: ChatMessage = {
+                id: assistantMessageId,
+                role: 'assistant',
+                content: accumulatedContent,
+                tool_calls,
+            };
+            dispatch({
+                type: 'ADD_CHAT_MESSAGE',
+                storyId: currentStory.id,
+                message: assistantMessage,
+            });
+
+            if (tool_calls) {
+                const toolMessages: ChatMessage[] = [];
+                for (const tool of tool_calls) {
+                    if (tool.function.name === 'test') {
+                        const message: ChatMessage = {
+                            id: crypto.randomUUID(),
+                            role: 'tool',
+                            content: `Test successful, received: ${JSON.stringify(tool.function.arguments)}`,
+                            tool_call_id: tool.id,
+                        };
+                        dispatch({
+                            type: 'ADD_CHAT_MESSAGE',
+                            storyId: currentStory.id,
+                            message,
+                        });
+                        toolMessages.push(message);
+                    }
+                }
+
+                return sendMessage([...newMessages, assistantMessage, ...toolMessages]);
+            }
         } catch (err) {
             const errorMessage = err instanceof Error
                 ? err.message
                 : 'Failed to generate response';
 
             setError(errorMessage);
+        }
+    }, [appState, currentStory, connection, model]);
+
+    const handleSendMessage = useCallback(async () => {
+        if (!currentStory || !input.trim() || !connection || !model || isLoading) return;
+
+        const userMessage = {
+            id: crypto.randomUUID(),
+            role: 'user' as const,
+            content: input.trim(),
+        };
+
+        setInput('');
+        setIsLoading(true);
+        setError(null);
+
+        try {
+            await sendMessage([userMessage]);
         } finally {
             setIsLoading(false);
-            abortControllerRef.current = null;
+            abortControllerRef.current = new AbortController();
         }
-    };
+    }, [currentStory, input, connection, model, isLoading]);
 
     const handleKeyDown = (e: KeyboardEvent) => {
         if (e.key === 'Enter' && !e.shiftKey) {
             e.preventDefault();
-            sendMessage();
+            handleSendMessage();
         }
     };
 
@@ -169,7 +220,7 @@ export const ChatSidebar = () => {
                         />
                         <button
                             class={styles.sendButton}
-                            onClick={sendMessage}
+                            onClick={handleSendMessage}
                             disabled={isDisabled || !input.trim()}
                         >
                             {isLoading ? 'Sending...' : 'Send'}
diff --git a/src/games/storywriter/contexts/state.tsx b/src/games/storywriter/contexts/state.tsx
index ad93b5b..ebf8527 100644
--- a/src/games/storywriter/contexts/state.tsx
+++ b/src/games/storywriter/contexts/state.tsx
@@ -6,10 +6,8 @@ import { useStoredReducer } from "@common/hooks/useStoredState";
 
 // ─── Types ────────────────────────────────────────────────────────────────────
 
-export interface ChatMessage {
+export type ChatMessage = LLM.ChatMessage & {
     id: string;
-    role: 'user' | 'assistant' | 'system';
-    content: string;
 }
 
 export interface Story {
diff --git a/src/games/storywriter/utils/llm.ts b/src/games/storywriter/utils/llm.ts
index 3c19bbc..876c297 100644
--- a/src/games/storywriter/utils/llm.ts
+++ b/src/games/storywriter/utils/llm.ts
@@ -1,20 +1,95 @@
 import { formatError } from '@common/errors';
-import Lock from '@common/lock';
-import SSE, { type SSEEvent } from '@common/sse';
+import SSE from '@common/sse';
 
 namespace LLM {
     export interface Connection {
         url: string;
         apiKey: string;
     }
-    export interface ChatMessage {
-        role: 'system' | 'user' | 'assistant';
+
+    export interface ToolCall {
+        id: string;
+        type: 'function';
+        function: {
+            name: string;
+            arguments: string | Record<string, any>; // JSON string
+        };
+    }
+
+    interface ChatMessageUser {
+        role: 'user';
         content: string;
     }
 
+    interface ChatMessageAssistant {
+        role: 'assistant';
+        content: string;
+        tool_calls?: ToolCall[];
+    }
+
+    interface ChatMessageSystem {
+        role: 'system';
+        content: string;
+    }
+
+    interface ChatMessageTool {
+        role: 'tool';
+        content: string;
+        tool_call_id?: string;
+    }
+
+    export type ChatMessage = ChatMessageUser | ChatMessageAssistant | ChatMessageSystem | ChatMessageTool;
+
+    export interface ToolStringParameter {
+        type: 'string';
+        enum?: string[];
+        description?: string;
+    }
+
+    export interface ToolNumberParameter {
+        type: 'number' | 'integer';
+        enum?: number[];
+        description?: string;
+    }
+
+    export interface ToolBooleanParameter {
+        type: 'boolean';
+        enum?: boolean[];
+        description?: string;
+    }
+
+    export interface ToolArrayParameter {
+        type: 'array';
+        description?: string;
+        items: ToolParameter;
+    }
+
+    export interface ToolObjectParameter {
+        type: 'object';
+        description?: string;
+        properties: Record<string, ToolParameter>;
+        required?: string[];
+    }
+
+    export type ToolParameter = ToolStringParameter | ToolNumberParameter | ToolBooleanParameter | ToolArrayParameter | ToolObjectParameter;
+
+    export interface Tool {
+        type: 'function';
+        function: {
+            name: string;
+            description?: string;
+            parameters: {
+                type: 'object';
+                properties: Record<string, ToolParameter>;
+                required?: string[];
+            };
+        };
+    }
+
     export interface ChatCompletionRequest {
         model: string;
         messages: ChatMessage[];
+        tools?: Tool[];
         temperature?: number;
         max_tokens?: number;
         stop?: string | string[];
@@ -27,7 +102,7 @@ namespace LLM {
     export interface ChatCompletionChoice {
         index: number;
         message: ChatMessage;
-        finish_reason: 'stop' | 'length' | 'content_filter';
+        finish_reason: 'stop' | 'tool_calls';
     }
 
     export interface ChatCompletionResponse {
@@ -46,8 +121,8 @@ namespace LLM {
 
     export interface ChatCompletionChunkChoice {
         index: number;
-        delta: { role?: string; content?: string };
-        finish_reason: 'stop' | 'length' | 'content_filter' | null;
+        delta: { role?: string; content?: string; tool_calls?: ToolCall[] };
+        finish_reason: 'stop' | 'tool_calls' | null;
     }
 
     export interface ChatCompletionChunk {
@@ -63,6 +138,7 @@ namespace LLM {
         object: 'model';
         created: number;
         owned_by: string;
+        support_tools: boolean;
         max_context?: number;
         max_length?: number;
     }
@@ -134,8 +210,6 @@ namespace LLM {
                     if (closed) return;
                     closed = true;
                     controller.close();
-
-                    console.log(formatError(e));
                 };
 
                 sse.addEventListener('error', handleEnd);
diff --git a/src/games/storywriter/utils/prompt.ts b/src/games/storywriter/utils/prompt.ts
index 16ead8a..d53f64e 100644
--- a/src/games/storywriter/utils/prompt.ts
+++ b/src/games/storywriter/utils/prompt.ts
@@ -2,7 +2,27 @@ import LLM from "./llm";
 import type { AppState } from "../contexts/state";
 
 namespace Prompt {
-    export function compilePrompt(state: AppState, newMessage?: LLM.ChatMessage): LLM.ChatCompletionRequest | null {
+    const tools: LLM.Tool[] = [
+        {
+            type: 'function',
+            function: {
+                name: 'test',
+                description: 'A simple test function',
+                parameters: {
+                    type: 'object',
+                    properties: {
+                        message: {
+                            type: 'string',
+                            description: 'The test message',
+                        },
+                    },
+                    required: ['message'],
+                },
+            },
+        },
+    ];
+
+    export function compilePrompt(state: AppState, newMessages: LLM.ChatMessage[] = []): LLM.ChatCompletionRequest | null {
         const { currentStory, model } = state;
 
         if (!currentStory || !model) {
@@ -15,13 +35,12 @@ namespace Prompt {
             ...currentStory.chatMessages,
         ];
 
-        if (newMessage) {
-            messages.push(newMessage);
-        }
+        messages.push(...newMessages);
 
         return {
             model,
             messages,
+            tools,
             // TODO banned_tokens
         };
     }