A local tool hides names before confidential docs go to an LLM
Lethe is a local tool that finds names of people and counterparties in confidential documents and replaces them with stable fake labels. It accepts Word, PowerPoint, PDF, and Excel files, then returns a file in the same format plus a job ID.
The same real name always becomes the same token, so an LLM can still follow who is who without seeing the real names. The user can send the file to any LLM, then paste the LLM’s output back into Lethe with the job ID to restore the real names.
This can work even when the output is a different kind of document, such as a summary, rewrite, or translation. The processing is local, with no cloud service, no API key, and no telemetry claimed.
Key points
- It supports Word, PowerPoint, PDF, and Excel files.
- It replaces people and counterparty names with tokens such as [PERSON_001].
- The same name keeps the same token, which helps the LLM follow the document.
- A job ID lets the tool restore real names after the LLM produces an answer.
- It claims to run locally without a cloud service, API key, or telemetry.