---
title: How To Write With An LLM
link: https://simonwillison.net/2026/Sep/17/how-to-write-with-an-llm/
source: simonwillison-net
published: 2026-09-17T23:37:27Z
updated: 2026-09-17T23:37:27Z
first_seen: 2026-09-18T01:14:43.309993603Z
labels:
- ai
- generative-ai
- llms
- thomas-ptacek
- writing
summary: 'How To Write With An LLM Thomas Ptacek on using LLMs as copyeditors, not as writing assistants: Rule Number One: You may not use a single word an LLM suggests to you. [...] I think that as a form of intellectual personal protective equipment you should adopt the rule that any specific turn of phrase an LLM suggests is off limits. Be strict about the rule! I won''t let LLMs write content for my blog, but I use them for fact-checking, spelling and grammar and as an occasional thesaurus (see my proofreading prompt). The rule to never use a turn of phrase suggested by an LLM feels good to me. The text has that weird smell to it, and it''s also a good principle to help stay disciplined. Later in this piece Thomas shows a screenshot of his personal LLM copyediting tool (see also this Twitter thread), and provides a prompt to help kickstart building your own. Tags: thomas-ptacek, writing, ai, generative-ai, llms'
content: extracted
html: 2026-09-17-how-to-write-with-an-llm.html
---

**[How To Write With An LLM](https://sockpuppet.org/blog/2026/09/17/how-to-write-with-an-llm/)**. Thomas Ptacek on using LLMs as copyeditors, not as writing assistants:

> **Rule Number One: You may not use a single word an LLM suggests to you.**
>
> \[...\] I think that as a form of intellectual personal protective equipment you should adopt the rule that any specific turn of phrase an LLM suggests is off limits. Be strict about the rule!

I won't let LLMs write content for my blog, but I use them for fact-checking, spelling and grammar and as an occasional thesaurus (see [my proofreading prompt](https://simonwillison.net/guides/agentic-engineering-patterns/prompts/#proofreader)).

The rule to never use a turn of phrase suggested by an LLM feels good to me. The text has that weird smell to it, and it's also a good principle to help stay disciplined.

Later in this piece Thomas shows a screenshot of his personal LLM copyediting tool (see also [this Twitter thread](https://x.com/tqbf/status/2100414465187475821)), and provides a prompt to help kickstart building your own.