# Self‑Correcting LangGraph Agent

This repository contains a minimal implementation of a **self‑correcting agent** using LangGraph.  The agent:

1. Executes a user‑supplied task via an unreliable tool that may fail.
2. Uses an LLM judge to verify the result (must answer `success` or `failed`).
3. Retries until the result is judged `success` or a maximum number of attempts is reached.

The implementation follows the specification from the course assignment.

## Requirements

The project uses the following packages (all versions are >= 1.0.0):

* `langchain>=1.0.0`
* `langgraph>=1.0.0`
* `langchain-openai>=0.2.0`

Install them via:

```bash
pip install -r requirements.txt
```

## Usage

```bash
# Run the agent for a simple arithmetic task
python agent.py "2+2"
```

You can also specify the maximum number of attempts:

```bash
python agent.py "2+2" --max_attempts 5
```

The output will show the number of attempts and the final status.

## How it works

* **`unreliable_tool`** – a function that evaluates the task string with a 30 % chance of raising a `ValueError`.
* **`execute_task`** – calls the tool and stores the result or error.
* **`verify_result`** – asks the LLM to judge the result. The LLM must reply with either `success` or `failed`.
* **`handle_error`** – increments the attempt counter and resets the state for a retry.
* **Graph** – a LangGraph `StateGraph` that loops between these nodes until success or the attempt limit is reached.

## Extending

Replace `unreliable_tool` with any external API or function.  Adjust the LLM prompt in `verify_result` to fit your domain.