How To Write With An LLM
- ID
- 25770
- Status
- summarized
- Published
- 18 Sep 2026, 7:37 AM
- Fetched
- 18 Sep 2026, 11:12 PM
- Provider
- Simon Willison
- Category
- developer-ai
- Original URL
- https://simonwillison.net/2026/Sep/17/how-to-write-with-an-llm/
- Source URL
- https://simonwillison.net/atom/everything/
Summary
- Score
- 6.5
- Created
- 18 Sep 2026, 11:13 PM
- Tags
- Audience
- developersvibe_codersai_agent_userssaas_founders
What happened
Simon Willison links to Thomas Ptacek's rule for using LLMs as copyeditors rather than writing assistants: never accept a specific turn of phrase an LLM suggests, but do use them for fact-checking, spelling, grammar, and as a thesaurus. Ptacek shares a screenshot of his personal LLM copyediting tool and a starter prompt for building your own.
Why it matters
If you ship blog posts, docs, or marketing copy with LLM assistance, adopt Ptacek's hard rule—ban LLM-suggested phrasing outright—to avoid the recognizable 'LLM smell' in your output while still getting value from fact-checking and proofreading prompts. Grab his starter prompt and build a lightweight copyediting tool for your own writing pipeline.
Discussion angle
Compare Ptacek's 'never use LLM phrasing' rule against your own current LLM writing workflow—where do you draw the line between LLM as editor vs. LLM as author, and what prompts have actually worked for proofreading without leaking voice?