## Documentation Index

Fetch the complete documentation index at: [/llms.txt](https://dev.writer.com/llms.txt)

Use this file to discover all available pages before exploring further.

In this tutorial, you’ll use the Writer Framework to create a simple yet powerful chat assistant that can engage in conversations on various topics, provide answers to your questions, and maybe even help you when you’re experiencing writer’s block! The process will take only minutes using a drag-and-drop visual editor to build the user interface and Python for the back-end code. Here’s what the finished project will look like:

## Prerequisites

Before starting, ensure you have:

- **A Writer account:** You don’t need an account to use Writer Framework, but you’ll need one to use the AI module. [Sign up for a free account here](https://app.writer.com/register).
- **Python 3.9.2 or later**: Use the installer from [python.org](https://www.python.org/downloads/).
- **pip:** This command-line application comes with Python and is used for installing Python packages, including those from Writer.
- **A basic understanding of Python:** You should be familiar with the basics of the language.
- **Your favorite code editor (optional):** There’s a code editor built into Writer for editing back-end code, but you can also use Visual Studio Code, Notepad++, Vim, Emacs, or any text editor made for programming if you prefer.

## Setting up your project

### Create a Writer app and get its API key

First, you’ll need to create a new app within Writer.

1. **Create the app in Writer**  
Log into Writer. From the Home screen, click on the **Build an app** button.   
The **Start building** menu will appear, presenting options for the types of apps you can create. Select **Framework**, located under **Developer tools**. This will create a brand new app based on Writer Framework.

2. **Copy your app's API key**  
On the next screen, titled **How to deploy an application**, you can get the API key for the app by clicking on the **Reveal key** button, located under the text **Authenticate with an API key**. Your complete API key will be displayed, and a “copy” button will appear. Click this button to copy the key; you’ll use it in the next step.

### Set up your computer and create the app’s project

The next step is to set up the Writer Framework environment on your computer. You’ll do this by creating a directory for the project, installing dependencies, and creating the project for the application using a template.

1. **Open your terminal application**  
Open your terminal application. On macOS and Linux, this application goes by the name _Terminal_; on Windows, you can use either _Windows PowerShell_ (which is preferred) or _Command Prompt_.

2. **Install the dependencies**  
If you already have the `writer` and `python-dotenv` packages installed on your computer, you can skip this step.  
Install the `writer` and `python-dotenv` packages by entering the following commands in your terminal application:
   
   ```
   pip install writer python-dotenv
   ```  
   This command tells `pip`, the Python package installer, to install two packages:

- `writer`, which provides some command-line commands and enables Python code to interact with Writer and the Writer Framework.
   - `python-dotenv`, which makes it easy to manage environment variables by loading them from a `.env` file. This one is optional for this exercise, but you might find it useful when working on larger projects.

3. **Set the API key environment variable**  
To pass your API key to the Writer Framework, you need to set an environment variable called `WRITER_API_KEY`. Select your operating system and terminal application below, then copy and paste the command into your terminal application, replacing `[your_api_key]` with the API key you copied earlier:

- macOS/Linux (Terminal)
   ```
   export WRITER_API_KEY=[your_api_key]
   ```  
   - On Windows (Windows PowerShell)
   ```
   $env:WRITER_API_KEY=[your_api_key]
   ```  
   - On Windows (Command Prompt)
   ```
   set WRITER_API_KEY=[your_api_key]
   ```  
   The `WRITER_API_KEY` environment variable will remain defined as long your terminal session is open (that is, until you close your terminal application’s window).

4. **Create the project**  
Create the project by entering this command into your terminal application:
   
   ```
   writer create chat-assistant --template=ai-starter
   ```  
   This command sets up a new project called `chat-assistant` using a starter template called `ai-starter` so that you’re not starting “from scratch.”

## Build the UI

Now that you’ve created the project, it’s time to define the UI. The Writer Framework’s drag-and-drop capabilities make it easy — even if you haven’t done much UI work before! The project editor is a web application that runs on your computer and enables you to define and edit your app’s user interface. Launch it by typing the following into your terminal application:
   
   ```
   writer edit chat-assistant
   ```  
   You’ll see a URL. Control-click it (command-click on macOS) to open it, or copy the URL and paste it into the address bar of a browser window. The browser window will contain the project editor, which will look like this:

### Examine the header

Select the **Header** component by clicking it — it’s the component at the top, containing the title **AI STARTER** and a gray area labeled **Empty Header**. When you click it, you’ll see the **properties** panel appear on the right side of the page. This lets you view and edit the properties of the selected component.

The first property you’ll see in the panel is the **Text** property, which defines the text that appears as the header’s title. It should contain the value `@{my_app.title}`. The `@{` and `}` indicate that `my_app.title` is a variable and that its contents should be the text displayed instead of the literal text “my_app.title”. You’ll set the value of this variable soon.

### Clear the Section's default title

Select the **Section** component by clicking it — it’s just below the **Header** component and contains the title **Section Title** and a gray area labeled **Empty Section**. In the **properties** panel, clear out the value of the **Title** property. This will remove the **Section**’s default title.

### Add a Text component to the Section

Drag a **Text** component from the **Core toolkit** panel on the left (it’s under **Content**, and you may need to scroll down a little to find it) and into the _Section_. Sections can act as containers for other components.

You can search for a specific component by using the search bar at the top of the **Core toolkit** panel.

Select the **Text** component. In the **properties** panel, set the **Text** property to provide instructions or context for your chat assistant. Here’s an example: `Welcome to the Chat Assistant. Ask me anything!`

### Add a Chatbot component to the Section

The heart of this app is the **Chatbot** component, a pre-built component that displays the conversation between the LLM and the user and provides a text field where the user can enter prompts. Drag a **Chatbot** component from the **Core toolkit** panel (it’s under **Content**) into the _Section_, just below the Text box.

## Add the back-end code

With the UI laid out, it’s time to work on the logic behind it. The logic behind the user interface is defined in a file named `main.py`, which is in your project’s directory. This file was automatically generated; you’ll update the code in it to define the behavior of your app. The simplest way to edit `main.py` is within the project editor. Click on the “toggle code” button (beside the word **Code**) near the lower left corner of the project editor page.

A pane with the name **Code** will appear at the bottom half of the screen, displaying an editor for the  the contents of `main.py`.

If you’d rather use a code editor instead of coding in the browser, use it to open the `main.py` file in your project’s directory.

### Import libraries and load the Writer Framework API key

You should see the following at the start of the file:
   
   ```
   import writer as wf
   import writer.ai
   ```  
   Replace that code with the following:
   
   ```
   import os
   import writer as wf
   import writer.ai

# Set the API key
   wf.api_key = os.getenv("WRITER_API_KEY")
   ```  
   This code imports the libraries that the application will need and then reads your Writer Framework API key in the `WRITER_API_KEY` environment variable.

### Create a handler to respond to the user's input

The application needs a function to handle incoming chat messages. Find these comments in the code…
   
   ```
   # Welcome to Writer Framework!
   # This template is a starting point for your AI apps.
   # More documentation is available at https://dev.writer.com/framework
   ```
   …and replace them with the following function:
   
   ```
   def generate_completion(state, payload):
     print(f"Here's what the user entered: {payload['content']}")
     state["conversation"] += payload
     print(f"Conversation: {state['conversation'].messages}")
     try:
         for index, chunk in enumerate(state["conversation"].stream_complete()):
             print(f"Chunk {index}: {chunk}")
             if not chunk.get("content"):
                 chunk["content"] = ""
             state["conversation"] += chunk

print(f"state['conversation']:\n{state['conversation'].messages}")
     except Exception as e:
         print(f"Error during stream_complete: {e}")
   ```  
   The `generate_completion()` function will be called when the user enters a prompt, which is contained in the `payload` object. The `payload` object is added to the `conversation` object contained in the application’s `state`, which adds the user’s prompt to the record of the conversation between the user and the LLM. After adding the user’s prompt to the conversational record, `generate_completion()` calls the `conversation` object’s `stream_complete()` method, which generates an LLM completion based on the conversation so far. As its name implies, `stream_complete()` returns the completion as a stream of text chunks, which are captured and added to the `conversation` object.
   
   The `conversation` object in the code above is an instance of Writer’s `Conversation` class. You can find out more about this class on our [_Writer AI module_](https://dev.writer.com/framework/ai-module) page.

### Initialize the application

The final step is to set the application’s initial state. Find this code, which should be just after the `generate_completion()` function…
   
   ```
   # Initialise the state
   wf.init_state({
       "my_app": {
           "title": "AI STARTER"
       },
   })
   ```
   …and replace it with this:
   
   ```
   # Initialize the state
   wf.init_state({
       "conversation": writer.ai.Conversation(),
       "my_app": {
           "title": "CHAT ASSISTANT"
       },
   })
   ```  
   The Writer Framework’s `init_state()` method sets the initial value of `state`, a dictionary containing values that define the state of the application. The key-value pairs in `state` are how you store values used by your app and how you pass data between the back-end code and the UI. The code above sets the initial value of `state` so that it has two key-value pairs:

- `conversation`: An object that keeps a record of the conversation that the user is having with the LLM. You’ll bind its value to the **Chatbot** component soon.
   - `my_app`: A dictionary containing values that define the application’s appearance. This dictionary has a single key-value pair, `title`, which defines the text that appears as the application’s title in the **Header**.

### Save the updated code and hide the code editor

That’s all the code. If you edited the code in the browser, save it by clicking the “save” button near the top right corner of the code editor.  Click the “toggle code” button to hide the code editor.

## Bind the UI to the back-end code

You’ve built the UI and written the code behind it. Let’s connect the two! Go back to the browser window with the project editor and do the following:

1. **Observe that the heading at the top of the app is now 'CHATBOT ASSISTANT'**  
Earlier, you saw that the **Header** component’s **Text** property was set to `@{my_app.title}`, a value in the app’s `state` variable. You changed this value when you update the call to the Writer Framework’s `init_state()` method.

2. **Bind the Chatbot component to the 'state' variable's 'conversation' key**  
Recall that the `conversation` object contained within the `state` variable contains the record of the conversation that the user is having with the LLM. Binding the **Chatbot** component to this object allows it to display the conversation to the user. Select the **Chatbot** component. In the **properties** panel, find the **Conversation** property and set its value to `@{conversation}`.

3. **Specify the Chatbot component's event handler**  
You need to specify that the **Chatbot** component should call the `generate_completion()` function when the user enters a prompt. Do this by scrolling down the **properties** panel to the **Events** section until you see a property called **`wf_chatbot_message`**. Select **`generate_completion`** from its menu.

## Test the application

You’ve completed all the steps to make a working chat assistant, and you can try using it right now, even while editing the user interface! Try entering some prompts into the text entry at the bottom of the **Chatbot** component. The LLM should respond accordingly: 
To get a better sense of what the experience will be like for the user, switch to the preview by changing the edit mode (located near the upper left corner of the page) from _UI_ mode to _Preview_ mode by selecting the **Preview** option: 
Here’s what the app looks like in _Preview_ mode: 
You can see the output of any `print()` functions and error messages by clicking on the **Log** button located near the upper right corner of the page: 
Here’s what the app looks like when displaying the log: 
It’s very helpful to be able to test the application while editing it. As you continue to work with Writer Framework, you’ll find yourself alternating between making changes to your application and testing those changes without having to leave the project editor.

## Run the application locally

Once you’ve tested the application, it’s time to run it locally. Switch back to your terminal application. Stop the project editor with ctrl-c, then run the application by entering the following command:
   
   ```
   writer run chat-assistant
   ```  
   Note that the command starts with `writer run` as opposed to `writer edit`. This launches the application as your users will see it, without any of the editing tools. Even though you can preview your applications in the project editor, it’s still a good idea to test it by running it on your computer, outside the project editor, before deploying it. You’ll be able to access the application with your browser at the URL that appears on the command line. It should look like this:

## Conclusion

That’s it — you’ve built a functional chat assistant using the Writer Framework! Feel free to modify this project! The Writer platform is flexible enough for you to customize, extend, and evolve your application into something completely different! To find out what else you can do, check out the documentation for [Writer Framework](https://dev.writer.com/framework/introduction) and the [Writer API](https://dev.writer.com/introduction).