LlamaIndex

apiVersion: v1
runtime: python3.12
entrypoint: agent.py:agent
dependencies: requirements.txt

llama-index-core>=0.14
llama-index-llms-openai

from llama_index.core.agent.workflow import FunctionAgent
from llama_index.llms.openai import OpenAI


def word_count(text: str) -> int:
    """Counts the words in a piece of text."""
    return len(text.split())


# Reads OPENAI_API_KEY, which you add as a secret on the agent's Config tab.
agent = FunctionAgent(
    tools=[word_count],
    llm=OpenAI(model="gpt-5"),
    system_prompt="Count the words in what the user says, then answer.",
)