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Cortex — Local Second Brain

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Overview

Indexes what you read locally. Semantic search & connections — nothing leaves your machine. Solely built by Shailesh Kumar.

Cortex remembers the web pages you read, so you can find them later by what they said, not just by URL. Type "that article about AI agents from last week" or "which site mentioned remote work in Charlotte" — Cortex finds it. Ask questions about anything you've read and get answers with citations to the original sources. WHAT MAKES CORTEX DIFFERENT - Runs 100% on your device. The AI model is bundled with the extension — Cortex makes zero network calls during normal use. - Free forever. No accounts, no subscriptions, no data collection. - Open source. Audit the code yourself if you want to verify the privacy claims. - Works on every page you read, automatically. No bookmarking required. HOW IT WORKS After install, browse normally. Cortex extracts the readable text from pages you visit and stores it in your browser's local database. Press Cmd+Shift+K (Mac) or Ctrl+Shift+K (Windows) anywhere to open the search overlay. Three modes: SEARCH — Find pages by content, not just URLs. Hybrid keyword + semantic search returns relevant pages even when you don't remember exact words. ASK — Get synthesized answers with inline citations. "Summarize what I read about React server components" returns a paragraph with linked sources. TODAY — A daily digest of what you read yesterday or in the last week. Top topics, notable findings, a narrative summary of your day. PRIVACY Indexed text stays in your browser. The embedding model is bundled — no remote model downloads. Sensitive sites (banking, healthcare, password managers, email) are skipped automatically. You can pause indexing or block specific domains anytime. Optional Cloud Chat (off by default): if you want richer answers for complex questions, you can add your own Google Gemini API key. When enabled, only the retrieved snippets needed to answer your question are sent to Gemini — never your full library. KEYBOARD SHORTCUTS - Cmd+Shift+K (Mac) / Ctrl+Shift+K (Windows): Open search overlay - Alt+Shift+C: Alternative shortcut if the primary conflicts - ↑↓: Navigate results - Enter: Open result - Cmd/Ctrl+Enter: Open in background tab - Esc: Close overlay

Details

  • Version
    1.0.1
  • Updated
    May 21, 2026
  • Offered by
    shailesh.entrant
  • Size
    16.18MiB
  • Languages
    English
  • Developer
    Email
    shailesh.entrant@gmail.com
  • Non-trader
    This developer has not identified itself as a trader. For consumers in the European Union, please note that consumer rights do not apply to contracts between you and this developer.

Privacy

Manage extensions and learn how they're being used in your organization

Cortex — Local Second Brain has disclosed the following information regarding the collection and usage of your data. More detailed information can be found in the developer's privacy policy.

Cortex — Local Second Brain handles the following:

Web history
User activity
Website content

This developer declares that your data is

  • Not being sold to third parties, outside of the approved use cases
  • Not being used or transferred for purposes that are unrelated to the item's core functionality
  • Not being used or transferred to determine creditworthiness or for lending purposes

Support

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