### Setting Up a Custom GPT with `server.py`, `instructions.txt`, and `openai.yaml`

This guide will help you set up and run a Custom GPT using OpenAI's "Custom GPT" feature by hosting your own API endpoint using `server.py` with `uvicorn` and `ngrok`.

#### 1. **Place Your Files**
Ensure the following files are properly set up:

- **`server.py`** – Your FastAPI-based server that serves as the backend for the GPT actions.
- **`instructions.txt`** – Custom instructions that define how the GPT should behave.
- **`openai.yaml`** – The configuration file that specifies API endpoint details.

Keep these files in a dedicated project directory.

#### 2. **Run `server.py` Locally**
You'll need to start your FastAPI server using `uvicorn`:

1. Install dependencies (if not already installed):

   ```bash
   pip install fastapi uvicorn
   ```

2. Run the server:

   ```bash
   uvicorn server:app --host 0.0.0.0 --port 8000
   ```

   This will start the API server locally at `http://127.0.0.1:8000`.

#### 3. **Expose the Server Using Ngrok**
To make your local server accessible to OpenAI’s API, use `ngrok`:

1. Install `ngrok` (if not installed):

   ```bash
   brew install ngrok  # macOS
   sudo apt install ngrok  # Debian/Ubuntu
   ```

   Or download it from [ngrok.com](https://ngrok.com/).

2. Start `ngrok` to expose port 8000:

   ```bash
   ngrok http 8000
   ```

   This will generate a public URL like `https://xyz.ngrok.io/`.

#### 4. **Update `openai.yaml`**
Edit your `openai.yaml` file and set the `base_url` to the ngrok-generated URL:

```yaml
base_url: "https://xyz.ngrok.io"
```

Replace `https://xyz.ngrok.io` with your actual `ngrok` URL.

#### 5. **Upload `openai.yaml` and `instructions.txt`**
- Open OpenAI's [Custom GPT](https://platform.openai.com/gpts).
- Click **Create** or **Edit** a Custom GPT.
- Upload `instructions.txt` and `openai.yaml` under **Advanced Settings**.

#### 6. **Test Your Custom GPT**
- After uploading, test interactions in the OpenAI interface.
- Ensure API calls to your `server.py` are working correctly.

#### Notes:
- Each time you restart `ngrok`, the public URL changes—update `openai.yaml` accordingly.
- Consider using an `ngrok` authtoken to maintain a stable URL.

This setup ensures your Custom GPT can call external actions via your locally hosted FastAPI server. 🚀