Claude Deep Think

Customize and toggle a reasoning instruction that is automatically appended to every message you send on claude.ai. Zero telemetry. Claude Deep Think lets you append a custom reasoning instruction to every message you send on claude.ai — so Claude always thinks deeply, without you copy-pasting the same prompt every time.

Features:

• Up to 5 prompt profiles (e.g., "Deep Reasoning", "Email Writing", "Code Analysis") — switch between them instantly from a floating chip on claude.ai
• Fully editable instructions — write exactly what you want appended
• One-click ON/OFF toggle — disable Deep Think for quick questions, re-enable for complex ones
• Works instantly — no page refresh needed when switching profiles or toggling
• Zero telemetry — no data leaves your browser, no analytics, no tracking, fully open source

How it works: 1. Install the extension 2. Visit claude.ai — you'll see the Deep Think chip in the bottom-right corner 3. Click "Switch" to manage your prompt profiles 4. Every message you send will have your active profile's instruction appended automatically, separated by a visible divider so you know it's there

Your instruction text is stored locally in your browser using Chrome's built-in storage. It is never sent anywhere except as part of your own message to Claude.

Source code: https://github.com/daiict218/claude-deep-think-ext