llm/docs/python-api.md
2023-07-10 11:42:23 -07:00

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# Python API
LLM provides a Python API for executing prompts, in addition to the command-line interface.
Understanding this API is also important for writing plugins.
## Basic usage
To run a prompt against the `gpt-3.5-turbo` model, run this:
```python
import llm
model = llm.get_model("gpt-3.5-turbo")
model.key = 'YOUR_API_KEY_HERE'
response = model.prompt("Five surprising names for a pet pelican")
print(response.text())
```
The `llm.get_model()` function accepts model names or aliases - so `chatgpt` would work here too.
Run this command to see a list of available models and their aliases:
```bash
llm models list
```
If you have set a `OPENAI_API_KEY` environment variable you can omit the `model.key = ` line.
### Models from plugins
Any models you have installed as plugins will also be available through this mechanism, for example to use Google's PaLM 2 model with [llm-palm](https://github.com/simonw/llm-palm)
```bash
pip install llm-palm
```
```python
import llm
model = llm.get_model("palm")
model.key = 'YOUR_API_KEY_HERE'
response = model.prompt("Five surprising names for a pet pelican")
print(response.text())
```
You can omit the `model.key = ` line for models that do not use an API key
## Concepts
The API consists of the following key concepts:
- `Model` - represents a language model against which prompts can be executed
- `Prompt` - a prompt that can be prepared and then executed against a model
- `Response` - the response executing a prompt against a model
- `Template` - a reusable template for generating prompts
### Prompt
A prompt object represents all of the information needed to be passed to the LLM. This could be a single prompt string, but it might also include a separate system prompt, various settings (for temperature etc) or even a JSON array of previous messages.
### Model
The `Model` class is an abstract base class that needs to be subclassed to provide a concrete implementation. Different LLMs will use different implementations of this class.
Model instances provide the following methods:
- `prompt(prompt: str, stream: bool, ...options) -> Response` - a convenience wrapper which creates a `Prompt` instance and then executes it. This is the most common way to use LLM models.
- `response(prompt: Prompt, stream: bool) -> Response` - execute a prepared Prompt instance against the model and return a `Response`.
Models usually return subclasses of `Response` that are specific to that model.
### Response
The response from an LLM. This could encapusulate a string of text, but for streaming APIs this class will be iterable, with each iteration yielding a short string of text as it is generated.
Calling `.text()` will return the full text of the response, waiting for the stream to stop executing if necessary.
### Template
Templates are reusable objects that can be used to generate prompts. They are used by the {ref}`prompt-templates` feature.