pocketflow/docs/utility_function/llm.md

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---
layout: default
title: "LLM Wrapper"
parent: "Utility Function"
nav_order: 1
---
# LLM Wrappers
We **don't** provide built-in LLM wrappers. Instead, please implement your own, for example by asking an assistant like ChatGPT or Claude. If you ask ChatGPT to "implement a `call_llm` function that takes a prompt and returns the LLM response," you shall get something like:
```python
def call_llm(prompt):
from openai import OpenAI
client = OpenAI(api_key="YOUR_API_KEY_HERE")
r = client.chat.completions.create(
model="gpt-4o",
messages=[{"role": "user", "content": prompt}]
)
return r.choices[0].message.content
# Example usage
call_llm("How are you?")
```
> Store the API key in an environment variable like OPENAI_API_KEY for security.
{: .note }
## Improvements
Feel free to enhance your `call_llm` function as needed. Here are examples:
- Handle chat history:
```python
def call_llm(messages):
from openai import OpenAI
client = OpenAI(api_key="YOUR_API_KEY_HERE")
r = client.chat.completions.create(
model="gpt-4o",
messages=messages
)
return r.choices[0].message.content
```
- Add in-memory caching
```python
from functools import lru_cache
@lru_cache(maxsize=1000)
def call_llm(prompt):
# Your implementation here
pass
```
> ⚠️ Caching conflicts with Node retries, as retries yield the same result.
>
> To address this, you could use cached results only if not retried.
{: .warning }
```python
from functools import lru_cache
@lru_cache(maxsize=1000)
def cached_call(prompt):
pass
def call_llm(prompt, use_cache):
if use_cache:
return cached_call(prompt)
# Call the underlying function directly
return cached_call.__wrapped__(prompt)
class SummarizeNode(Node):
def exec(self, text):
return call_llm(f"Summarize: {text}", self.cur_retry==0)
```
- Enable logging:
```python
def call_llm(prompt):
import logging
logging.info(f"Prompt: {prompt}")
response = ... # Your implementation here
logging.info(f"Response: {response}")
return response
```
## Why Not Provide Built-in LLM Wrappers?
I believe it is a **bad practice** to provide LLM-specific implementations in a general framework:
- **LLM APIs change frequently**. Hardcoding them makes maintenance a nightmare.
- You may need **flexibility** to switch vendors, use fine-tuned models, or deploy local LLMs.
- You may need **optimizations** like prompt caching, request batching, or response streaming.