PocketFlow

• Pocket Flow is a 100-line minimalist LLM framework

• Lightweight: Just 100 lines. Zero bloat, zero dependencies, zero vendor lock-in.

• Expressive: Everything you love—(Multi-)Agents, Workflow, RAG, and more.

• Agentic Coding: Let AI Agents (e.g., Cursor AI) build Agents—10x productivity boost!

See: The-Pocket/PocketFlow

!pip install pocketflow --quiet
!pip install litellm --quiet

from google.colab import drive
drive.mount('/content/drive')  # Add My Drive/<>

import os
os.chdir('drive/My Drive')
os.chdir('Books_Writings/NLPBook/')

Mounted at /content/drive

%run keys.ipynb

import os
from litellm import completion

def call_llm(messages):
  """Calls the litellm completion API with the given messages."""
  response = completion(
      model = "openai/gpt-4.1",
      messages=messages
  )
  return response.choices[0].message.content

# Test the LLM call
messages = [{"role": "user", "content": "In a few words, what's the meaning of life?"}]
response = call_llm(messages)
print(f"Prompt: {messages[0]['content']}")
print(f"Response: {response}")

Prompt: In a few words, what's the meaning of life?
Response: To seek connection, understanding, and fulfillment—making meaning in your own way.

from pocketflow import Node, Flow
# from utils import call_llm

class ChatNode(Node):
    def prep(self, shared):
        # Initialize messages if this is the first run
        if "messages" not in shared:
            shared["messages"] = []
            print("Welcome to the chat! Type 'exit' to end the conversation.")

        # Get user input
        user_input = input("\nYou: ")

        # Check if user wants to exit
        if user_input.lower() == 'exit':
            return None

        # Add user message to history
        shared["messages"].append({"role": "user", "content": user_input})

        # Return all messages for the LLM
        return shared["messages"]

    def exec(self, messages):
        if messages is None:
            return None

        # Call LLM with the entire conversation history
        response = call_llm(messages)
        return response

    def post(self, shared, prep_res, exec_res):
        if prep_res is None or exec_res is None:
            print("\nGoodbye!")
            return None  # End the conversation

        # Print the assistant's response
        print(f"\nAssistant: {exec_res}")

        # Add assistant message to history
        shared["messages"].append({"role": "assistant", "content": exec_res})

        # Loop back to continue the conversation
        return "continue"

# Create the flow with self-loop
chat_node = ChatNode()
chat_node - "continue" >> chat_node  # Loop back to continue conversation

flow = Flow(start=chat_node)

# Start the chat
shared = {}
flow.run(shared)

Welcome to the chat! Type 'exit' to end the conversation.

You: What is 1+2?

Assistant: 1 + 2 = **3**

You: exit

Goodbye!

/usr/local/lib/python3.12/dist-packages/pocketflow/__init__.py:44: UserWarning: Flow ends: 'None' not found in ['continue']
  if not nxt and curr.successors: warnings.warn(f"Flow ends: '{action}' not found in {list(curr.successors)}")