Nova is a Streamlit chat application powered by Mistral AI. The Streamlit
interface lives in app.py, while the reusable conversation and model logic
lives in chatmodels/main.py.
- Python 3.12 or newer
- uv
- A valid Mistral API key
Clone the repository and change into its directory, then run:
uv syncThis creates or updates the project virtual environment from pyproject.toml
and uv.lock.
Create a .env file in the project root:
MISTRAL_API_KEY="your_mistral_api_key"The application loads this value through python-dotenv. Keep .env local and
private; never commit it, paste it into the UI, or include the key in logs or
screenshots.
uv run streamlit run app.pyOpen the local URL printed by Streamlit, normally
http://localhost:8501. Enter a prompt and select Send to exercise the
full UI-to-model path.
uv run python -m chatmodels.mainType prompts at You: and type exit to end the session. The terminal mode
and Streamlit mode share the same get_reply() model function.
| File | Responsibility |
|---|---|
app.py |
Streamlit layout, CSS, form submission, display messages, and browser-session state. |
chatmodels/main.py |
Mistral client creation, LangChain message history, reply generation, and optional CLI entry point. |
pyproject.toml |
Project metadata and dependency declarations. |
uv.lock |
Locked dependency versions used by uv sync. |
.env |
Local-only credentials; do not commit. |
app.py imports new_conversation() and get_reply() from
chatmodels/main.py. The model module must not run an input() loop when it is
imported by Streamlit; the CLI loop is protected by its __main__ guard.
-
Push the repository to GitHub without
.env. -
Set
app.pyas the Streamlit app entry point. -
In Manage app → Settings → Secrets, add:
MISTRAL_API_KEY = "your_mistral_api_key"
-
Save the secret and reboot or redeploy the app.
The local .env file is not uploaded to Streamlit Cloud. A deployment that
loads the UI but returns 401 Unauthorized from api.mistral.ai has a missing,
invalid, revoked, or incorrectly named production secret. The expected name is
exactly MISTRAL_API_KEY.
| Symptom | Resolution |
|---|---|
streamlit: command not found |
Run uv sync and start it with uv run streamlit run app.py. |
UI loads but replies fail with 401 Unauthorized |
Check the Mistral key locally in .env or in Streamlit Cloud Secrets. |
| Local works but production fails | Configure MISTRAL_API_KEY in the deployment; local .env is not deployed. |
| Importing the model starts terminal input | Keep interactive code inside run_cli() and under if __name__ == "__main__":. |
For a user-oriented walkthrough, see USAGE.md.
