---
title: "Paste long documents into Claude without pasting your secrets."
description: "Claude handles long documents and whole codebases in one prompt — which means more sensitive data in a single paste. Locke masks it on-device before Anthropic sees it."
url: "https://sonomos.ai/for/claude/"
source: "https://sonomos.ai/for/claude/"
---

# Paste long documents into Claude without pasting your secrets.

Claude holds whole contracts, meeting transcripts, multi-file codebases and hundred-page PDFs in one prompt. So people paste the whole document, and one paste can carry far more regulated data than they realise.

Nobody re-reads a 40-page transcript for the one client account number before sending it to claude.ai or the Claude desktop app. The bigger the paste, the more rides along unnoticed.

Locke scans the full prompt, however long, for the identifiers a skim would miss. Claude still reasons over your whole document, minus the parts that shouldn't leave.

## The risk with Claude

Large context windows invite whole-document pastes. One prompt to Claude can carry far more sensitive data than a quick question, with the regulated fields buried too deep to spot by eye.

## How Locke helps

Locke scans the whole prompt on your device, end to end, and masks identifiers wherever they appear before the document reaches Anthropic.

## Locke is free for one person

It runs on your device and masks sensitive data before a prompt is sent, on the AI tools it covers. Teams starts at $14.99 per seat a month.

[Download Locke](https://sonomos.ai/downloads/)[Talk to the team](https://sonomos.ai/contact/)

## Locke for other AI tools

- [Locke for ChatGPT](https://sonomos.ai/for/chatgpt/)
- [Locke for Gemini](https://sonomos.ai/for/gemini/)
- [Locke for GitHub Copilot](https://sonomos.ai/for/github-copilot/)
- [Locke for Cursor](https://sonomos.ai/for/cursor/)
- [Locke for Ollama](https://sonomos.ai/for/ollama/)
- [Locke for Perplexity](https://sonomos.ai/for/perplexity/)
- [Locke for Microsoft Copilot](https://sonomos.ai/for/microsoft-copilot/)

## Reading on Claude

- [The Anthropic DPA Explained: Claude Data Processing Agreement Guide (2026)](https://sonomos.ai/blog/claude-dpa-explained-2026/)
- [Claude EU Data Residency in 2026: What Anthropic Offers, and What European Teams Do Instead](https://sonomos.ai/blog/claude-eu-data-residency-2026/)
- [Can My Employer See My Claude Chats? What's Visible in 2026 (and What Isn't)](https://sonomos.ai/blog/can-my-employer-see-my-claude-chats-2026/)
- [Is Claude Confidential? What Anthropic Can See, Store, and Train On (2026)](https://sonomos.ai/blog/is-claude-confidential-2026/)