Friday AI

What it is

Friday is a personal Windows assistant that lets a Gemini model trigger local Python skills: opening apps, organizing the Desktop, setting timers, managing todos and controlling volume. It runs from the system tray, with a hotkey-activated chat window, or as a terminal or web chat.

I built it to learn how LLM tool use works under the hood, so it deliberately avoids agent frameworks and the Gemini SDK.

How it works

• The agent sends the model a prompt with the available tools and the last few turns. The model answers in text or with a JSON object such as a tool name and its arguments.
• A tools registry maps each JSON call onto a Python function by inspecting its signature, and absorbs common argument-name differences.
• The API client lists the models available to the key, picks the first one that answers a probe, and retries with exponential backoff on rate limits.
• Each skill is imported on its own, so a missing optional dependency only disables that skill.

Limitations

• Single-step only: tool results are shown to the user but not sent back to the model, so it cannot chain actions.
• Tool calling is prompt-based (JSON in plain text), not Gemini's native function calling.
• Short memory: only the last three exchanges.

Possible next steps

Feed tool results back to the model, use native function calling, and expose the skills as an MCP server.