usai-api-tester

Disclaimer: This is an independent, open-source project. It is not an official product of, affiliated with, endorsed by, or sponsored by the U.S. Government, the General Services Administration (GSA), or any federal agency. USAi is a government service; this tool is a community-built utility for testing its API. Use at your own discretion.

A minimal CLI tool for testing and exploring the USAi federal government AI gateway API.

"It looks like you're trying to query a federal AI. Would you like help with that?"

What is USAi?

USAi provides a unified, OpenAI-compatible REST API that gives federal government users access to multiple LLM providers through a single gateway:

• Google: Gemini 2.5 Flash, Gemini 2.5 Pro
• Anthropic: Claude 3.5 Haiku, Claude Sonnet 4.5, Claude Opus 4.5
• Meta: Llama 3.2 11B, Llama 4 Maverick
• Embeddings: Cohere English v3

What does this app do?

This is a stateless API tester. Each prompt is an independent API call with no conversation history — exactly how the API works when you call it programmatically. It lets you:

• Verify your API key and connectivity
• Send prompts to any available model
• Compare responses across models using the same prompt
• Switch between models on the fly

This is not a chat application. It's a testing tool for people who will be building real integrations via code, agent workflows, or Jupyter notebooks.

Requirements

• Python 3.10 or higher
• A USAi API key (request through your agency's process)
• Your agency-specific USAi API endpoint URL

Setup

Windows (Command Prompt or PowerShell)

git clone https://github.com/brockwebb/usai-api-tester.git
cd usai-api-tester

python -m venv venv
venv\Scripts\activate

pip install -r requirements.txt

macOS / Linux

git clone https://github.com/brockwebb/usai-api-tester.git
cd usai-api-tester

python3 -m venv venv
source venv/bin/activate

pip install -r requirements.txt

Conda (any OS)

git clone https://github.com/brockwebb/usai-api-tester.git
cd usai-api-tester

conda create -n usai python=3.12 -y
conda activate usai

pip install -r requirements.txt

Configuration

API Key & Endpoint

On first run, the app will prompt you for your API key and base URL, then save them to a .env file (which is git-ignored — your key stays local).

You can also set them up manually:

cp .env.example .env

Then edit .env:

USAI_API_KEY=your-actual-key-here
USAI_BASE_URL=https://your-agency-endpoint.usai.gov

Your API base URL (endpoint) can be found in the USAi console under the API tab in the left menu.

API keys rotate every 7 days. When your key expires, the app will detect the 401 error and prompt you for a new one automatically.

Models & Defaults

Edit config.yaml to change the default model, adjust temperature, set a system prompt, or update the model list if USAi adds/removes models.

Usage

python usai_tester.py

Type a prompt and hit Enter. After each response, you get three options:

1. New prompt (default) — enter another prompt
2. Compare — send the same prompt to a different model and see both responses
3. Switch model — change your active model

Type quit, exit, or q to leave.

Troubleshooting

Problem	Fix
Connection failed	Check your base URL in .env. Make sure you're on your agency network / VPN.
401 Unauthorized	API key expired (7-day rotation). The app will prompt for a new one.
429 Too Many Requests	Rate limit is 3 calls/sec/key. Slow down or contact support@usai.gov.
ModuleNotFoundError	Make sure your virtual environment is activated and you ran pip install -r requirements.txt.

Project Structure

usai-api-tester/
├── .env.example      # Template for API key and base URL
├── .gitignore         # Keeps .env and other secrets out of git
├── config.yaml        # Models, defaults, non-secret configuration
├── LICENSE            # MIT
├── README.md          # You are here
├── requirements.txt   # Python dependencies
└── usai_tester.py     # The app (single file)

License

MIT

Support

For USAi API issues: support@usai.gov

For issues with this tester: open an issue