61 lines
2.0 KiB
Markdown
61 lines
2.0 KiB
Markdown
# Self‑Correcting LangGraph Agent
|
||
|
||
## Overview
|
||
|
||
This project implements a **self‑correcting agent** using LangGraph. The agent
|
||
performs a task, asks an LLM to judge the result, and retries automatically until
|
||
the result is judged **success** or the maximum number of attempts is reached.
|
||
|
||
The key components are:
|
||
|
||
| Component | Purpose |
|
||
|-----------|---------|
|
||
| `AgentState` | Typed state that tracks the task, result, attempts, status, error and max_attempts |
|
||
| `unreliable_tool` | Simulates a tool that fails 30 % of the time (used to demonstrate retry logic) |
|
||
| `verify_result` | LLM judge that must reply with the single word `success` or `failed` |
|
||
| `handle_error` | Resets the error and sets the status back to `pending` for a retry |
|
||
| `execute_task` | Runs the unreliable tool and updates the state |
|
||
| `create_agent` | Builds the LangGraph with the above nodes and a retry loop |
|
||
| `create_agent_executor` | Compiles the graph into a runnable executor |
|
||
| CLI | Run the agent from the command line: `python agent.py "2+2" --max 5` |
|
||
|
||
## How It Works
|
||
|
||
1. **Start** – The graph begins at `execute_task`.
|
||
2. **Execute** – The tool runs. If it throws an exception, the state status becomes `failed`.
|
||
3. **Check attempts** – If the number of attempts is >= `max_attempts`, the graph ends with status `max_attempts`.
|
||
4. **Verify** – The LLM judges the result. If the verdict is `success`, the graph ends. If `failed`, it goes to `handle_error`.
|
||
5. **Retry** – `handle_error` clears the error and sets status to `pending`, then the graph loops back to `execute_task`.
|
||
|
||
## Usage
|
||
|
||
```bash
|
||
# Install dependencies
|
||
pip install -r requirements.txt
|
||
|
||
# Run the agent
|
||
python agent.py "2+2" --max 5
|
||
```
|
||
|
||
The console will show the final state, e.g.:
|
||
|
||
```
|
||
--- Final State ---
|
||
result: 4
|
||
attempts: 2
|
||
status: success
|
||
error: None
|
||
max_attempts: 5
|
||
```
|
||
|
||
## Requirements
|
||
|
||
```text
|
||
langchain>=1.0.0
|
||
langgraph>=1.0.0
|
||
langchain-openai>=1.0.0
|
||
```
|
||
|
||
## Note
|
||
|
||
The agent uses the OpenAI API. Make sure the environment variable `OPENAI_API_KEY` is set. |