Explainer — understand what you read

Select text for simpler explanations with Gemini Nano or downloadable WebLLM models, examples, diagrams, and optional pictures.

**Select a passage. Understand it in plain language without leaving the page.** Explainer is a lightweight, privacy-first reading companion that turns dense paragraphs, technical jargon, and complex concepts into clear, structured explanations right where you are reading. Powered by Chrome’s built-in **Gemini Nano** on-device AI by default, your selected text stays on your computer—no API key, account, or cloud subscription required. ### ✨ Key Features * **Instant Plain-Language Explanations:** Highlight a word, sentence, or multi-paragraph passage (up to 24,000 characters) to get a clear breakdown, key definitions, and practical examples. * **Interactive Refinements:** Need a different angle? Click **Simpler**, **More detail**, or **Show example** inside the floating popup to adjust the explanation on the fly. * **Visual Learning Aids:** Automatically generates clean, locally rendered step-by-step process diagrams for causal chains and workflows, paired with optional reference images from Wikimedia Commons. * **Customizable Reading Experience:** Adjust your preferred reading level, choose your output language, and switch between Light, Dark, or System popup themes. * **Flexible Triggers:** Explain text automatically after highlighting, wait for a click on the floating "Explain" button, use the right-click context menu, or trigger on demand via keyboard shortcut (`Alt+Shift+E` on Windows/Linux, `Option+Shift+E` on macOS). * **Distraction-Free Controls:** Pin explanations to keep them open while you keep reading, press `Escape` to dismiss instantly, pause the extension globally with one click, or disable it on specific websites. --- ### 🔒 Private by Default (On-Device vs. Cloud AI) * **100% Local Default (Gemini Nano):** Explainer defaults to Chrome’s built-in on-device Gemini Nano model. No API key is needed, there is no automatic cloud fallback, and local explanations and diagrams work completely offline after initial setup. * **Optional Bring-Your-Own-Key (Gemini Cloud):** Prefer cloud speed or reading on a device that doesn't support local AI? You can optionally switch to Google’s Gemini API (`gemini-2.5-flash-lite` by default) using your own API key. Keys are stored only in your browser session by default (or optionally in local extension storage) and are never logged or exposed to web pages. * **Zero Tracking:** Explainer does not store your reading history, selected text, or past explanations, and includes zero analytics or telemetry. Password fields and editable text inputs are strictly ignored. --- ### ⚙️ System Requirements for On-Device AI (Gemini Nano) To use the default free, on-device Gemini Nano engine, your system must meet Chrome’s built-in AI requirements: * **Browser:** Desktop Chrome 138 or newer (Windows, macOS, or Linux; mobile platforms are not supported). * **Storage:** At least 22 GB of free disk space on your Chrome profile volume for model eligibility. * **Hardware:** A GPU with more than 4 GB VRAM, **or** at least 16 GB of RAM and 4 CPU cores. *(If your device does not meet these requirements, you can still use Explainer by configuring your own Gemini API key in Settings, or test the interface using the built-in Offline Demo Mode.)* --- ### 🚀 Quick Start Guide 1. Click the **Explainer** icon in your Chrome toolbar and open **Settings & AI setup**. 2. Keep **Gemini Nano · on this device** selected and click **Set up Gemini Nano** (keep the settings tab open while Chrome finishes downloading the local model). 3. Enable Explainer on your current site from the toolbar popup, or select **Allow on all websites** in Settings (reload any already-open tabs once after granting permission). 4. Highlight any text on an ordinary webpage and watch it become clear!