# Mask PII Before Sending Data to an LLM

> Strip names, emails, MRNs, and identifiers before sending a prompt to Claude, ChatGPT, Gemini, Perplexity, or DeepSeek.

Canonical: https://omna.dev/mask-pii-before-llm

Omna masks PII before the request leaves your machine. Two surfaces:

- **Browser extension / Mac app** — intercepts paste into Claude, ChatGPT, Gemini, Perplexity, DeepSeek and replaces PII with reversible tokens.
- **Python** — `df.omna.mask(columns=["note"])` for batch pipelines.

Tokens are mapped on-device. The mapping never leaves your machine.