Install Onhand
Onhand is live on the Chrome Web Store. The store currently serves and updates through Chrome.
- Open the Chrome Web Store listing.
- Click Add to Chrome and confirm the install prompt.
- Open the Onhand options page and choose Onhand Free, OpenAI Codex sign-in, or a provider API key.
- Pin Onhand, open a normal web page, and click the extension icon to open the side panel.
If you prefer a manual install or need a specific release artifact,
download the latest ZIP from GitHub releases,
unzip it, and load it from chrome://extensions with developer mode enabled.
Sign in or add a key
Open the Onhand options page and choose one provider path:
- Onhand Free: no account or API key. Daily usage is capped and anonymous diagnostics are required.
- OpenAI Codex sign-in: recommended for normal browser tutoring.
- Provider API key: useful for direct OpenAI, Anthropic, Gemini, or OpenRouter calls. OpenAI API keys can also power the Realtime voice tutor.
If Onhand says credentials are missing, open the options page, choose Onhand Free, sign in again, or paste your key, save, then reopen the side panel.
Voice tutor
Press Voice in the side panel to start the experimental realtime tutor. Your browser and macOS both need microphone access.
- If Chrome never reaches listening, check the site microphone permission and macOS Privacy & Security settings.
- If Onhand cannot create a Realtime session, confirm an OpenAI API key is saved or run the local session endpoint with
OPENAI_API_KEY=... npm run serve:realtime. - If voice works in one Chromium browser but not another, switch the microphone device in that browser and reload the extension.
PDFs and visual pages
Onhand works best when it can read page text directly. For PDFs, use the Onhand PDF viewer path when available. For equations, charts, and diagrams, Onhand may use a visible-region capture to ground the answer.
Report a bug
Please open a GitHub issue with the browser, page type, what you asked Onhand to do, and any visible error message.
If a failed Onhand reply shows Send anonymized error report, click it and include the returned report id in your issue. The report excludes prompts, page content, URLs, screenshots, transcripts, saved sessions, and keys.
Support development
If Onhand is useful to you, GitHub Sponsors helps support ongoing development and the hosted Onhand Free path.