Inline Context Lookup with Rabbitholes Chrome Extension

Description and use

The author built a Chrome extension called 'rabbitholes' that provides inline explanations for highlighted text using Claude Haiku 4.5. It uses Shadow DOM for style isolation and allows recursive exploration of terms without leaving the original page. No intermediary servers are used.

Problem

Reading long-form articles often requires looking up unfamiliar terms, forcing users to either open new tabs (losing context) or skip terms (losing understanding).

Outcome

A privacy-focused, client-side Chrome extension that provides recursive, inline context for reading without breaking flow or leaking data to intermediary servers.

Workflow

• Install the Rabbitholes Chrome extension.
• Configure the extension with a personal Anthropic API key stored in chrome.storage.sync.
• Highlight text in a web article to trigger an inline explanation from Claude Haiku 4.5.
• Click on specific words within the explanation to recursively explore deeper context.
• Use the hop depth counter to monitor how far the exploration has diverged from the original text.
• Optionally use the globe icon to re-answer queries with live Brave Search results for verification.
• Close the tooltip to return exactly to the previous reading position.

Evidence

So I built rabbitholes — a Chrome extension that renders an explanation next to your cursor when you highlight text, using a shadow DOM tooltip that doesn't touch the host page's layout or styles.

Source

No intermediary server. Requests go directly from your browser to api.anthropic.com. Zero telemetry, Manifest V3, your Anthropic key stored in chrome.storage.sync.

Source