🔍 Fact Checker — Agentic AI Fact-Checking CLI

An agentic AI pipeline that takes a plain-text claim, searches for evidence, and returns a credibility score from 0–100 with a justification.

🧭 Order of solving bugs

This is the preferred order to solve the issues, as it keeps the fixes incremental and easier to validate step by step.

1. Issue 1
2. Issue 2
3. Issue 3
4. Issue 4
5. Issue 5
6. Issue 6

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✨ What it does

$ poetry run python -m fact_checker_bugs.cli check "The Great Wall of China is visible from space."

╭──────────────────────────────────────────────────────────────╮
│ Evaluating: The Great Wall of China is visible from space.   │
╰──────────────────────────────────────────────────────────────╯

⠙ Agent is researching live data...

🟡 Credibility Score: 35/100

╭─ Justification ───────────────────────────────────────────────╮
│ Multiple scientific sources, including NASA astronaut reports │
│ and optical physics analysis, confirm that the wall is far too │
│ narrow (~10 m) to be seen by the naked eye from low Earth      │
│ orbit (~400 km). This is a well-documented myth...            │
╰───────────────────────────────────────────────────────────────╯

               Sources Consulted

┌──────────────────────────┬──────────────────────────────┐
│ Title                    │ URL                          │
├──────────────────────────┼──────────────────────────────┤
│ NASA Earth Observatory   │ https://earthobservatory...  │
│ Scientific American      │ https://scientificamerican.. │
└──────────────────────────┴──────────────────────────────┘

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🛠️ Prerequisites

Before setting up the project, make sure you have the following installed:

Tool	Version	Download
Python	>= 3.14	https://www.python.org/downloads/
Poetry	>= 2.0.0	https://python-poetry.org/docs/#installation
Git	Any recent version	https://git-scm.com/downloads

Verify your installations

python --version
poetry --version
git --version

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🚀 Setup Instructions

Step 1 — Clone the repository

git clone <repository-url>
cd fact_checker_bugs

Step 2 — Install dependencies

poetry install

Step 3 — Configure environment variables

Copy the example file:

cp .env.example .env

On Windows PowerShell:

Copy-Item .env.example .env

Fill in your keys in .env:

GEMINI_API_KEY_1=your_key_here
GEMINI_API_KEY_2=optional_second_key
TAVILY_API_KEY=your_tavily_key

Do not commit .env to version control.

Step 4 — Run the CLI

poetry run python -m fact_checker_bugs.cli check "Your claim goes here"

Example:

poetry run python -m fact_checker_bugs.cli check "The James Webb Space Telescope was launched in 2021."

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📁 Project Structure

fact_checker_bugs/
├── .env.example
├── .gitignore
├── pyproject.toml
├── poetry.lock
├── README.md
├── src/
│   └── fact_checker_bugs/
│       ├── __init__.py
│       ├── cli.py
│       ├── graph.py
│       ├── state.py
│       ├── nodes/
│       │   ├── __init__.py
│       │   ├── cross_referencer.py
│       │   ├── query_formulator.py
│       │   ├── retriever.py
│       │   └── scorer.py
│       └── utils/
│           ├── __init__.py
│           └── llm_utils.py
└── tests/
    └── __init__.py

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❓ Troubleshooting

No Gemini API keys found in environment

Check that your .env file exists and contains valid keys.

429 Too Many Requests

Wait a minute and try again, or add more Gemini keys to rotate between them.

Tavily search failed

Verify that TAVILY_API_KEY is set correctly in .env.

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🧰 Tech Stack

• LangGraph
• Google Gemini
• Tavily Search
• Typer
• Rich
• Poetry