Overview
A small AI tutor that runs entirely on your machine: in browsers with Chrome's built-in AI capability it answers technical questions locally with no API key, and everywhere else it falls back to a deterministic set of structured study answers. The last twelve exchanges are kept in your browser, and nothing is sent to a server.
How It Works
Type a technical question — IT, computer science, software engineering, or AI/ML topics work best — and press Ask tutor, or submit with Ctrl/Command plus Enter. Three example prompts sit above the input for one-click starts. Each answer displays with its source labelled: 'Chrome built-in AI' when the local model responded, 'CruxDev fallback' otherwise. A status pill near the header shows whether Chrome AI was detected on load.
Step-by-Step Usage Guide
- Check the status pill to see whether Chrome built-in AI is available.
- Type a question or click one of the three example prompts.
- Submit with the button or Ctrl/Command plus Enter.
- Read the source label on each answer to know which engine responded.
Technical Specifications & Standards
Capability detection checks for window.ai.languageModel, the shape of Chrome's built-in AI (Gemini Nano) API, and queries its capabilities to confirm availability before use; the detection deliberately uses the 'ai' in window guard so unsupported browsers take the fallback path cleanly rather than erroring. When available, a session is created per question with a fixed system prompt that constrains answers to under 220 words, forbids claiming code execution or web access, and asks for assumptions, an example, and a check — the session is destroyed after each answer. The fallback is not a hidden remote call: it pattern-matches your question against a handful of core topics (complexity, HTTP APIs, databases and indexing, ML evaluation) and returns a hand-written structured answer; anything else gets a generic study-strategy response that says outright that the local model is unavailable. The last twelve question-and-answer pairs persist under the localStorage key CruxDev-nano-ai-tutor-v1. Honest limits: answers come from a small local model, so treat them as a study starting point, not an authority.
Targeted Use Cases
- Getting a quick, private explanation of an unfamiliar systems concept.
- Rehearsing interview topics like circuit breakers or evaluation metrics.
- Studying in a offline or privacy-conscious setting where cloud AI is unwanted.
- Reviewing the last few explanations via the saved history.
Notes & Gotchas
- Ask specific questions with context; the 220-word answer budget rewards precision.
- Verify important claims — a small on-device model can be confidently wrong.
- Use the fallback topics to structure your own study when Chrome AI is unavailable.
- Clear site data if you want the local question history gone.
Frequently Asked Questions
Does this tool send my questions to a server?
No. When Chrome's built-in AI is present, the question is answered by the on-device model with no network call. When it is absent, a deterministic fallback runs in the page. Either way nothing leaves your browser.
Why does it say fallback mode?
The status pill shows fallback when the browser lacks the window.ai.languageModel capability — most non-Chrome browsers, or Chrome without the built-in AI feature enabled. The tool then answers a few core topics deterministically and says so honestly.
How long is the history kept?
The last twelve question-and-answer pairs are stored in localStorage under CruxDev-nano-ai-tutor-v1 and restored on your next visit. Clearing the site's data removes them; there is no server copy.
Can I trust the answers?
Treat them as study scaffolding. The local model is small and the fallback is static, so verify anything consequential against documentation — the tutor itself is prompted to state assumptions rather than overclaim.