About the notebook

Prompt Notebook is one person's working notes on prompt engineering, RAG, small-team AI plumbing, and the everyday failure modes that don't show up in launch posts.

It is written by Jules Ashton, an independent software engineer who spends about half of every week helping teams debug their LLM-powered products, and the other half building small internal tools of his own. This notebook is the byproduct — the things worth writing down after enough of a pattern shows up.

What is here

• Weekly-ish long-form notes on specific prompt patterns, with small evals when a claim is worth checking.
• Post-mortems on things that went wrong in agentic and RAG pipelines, written to be useful to the next person.
• Occasional short "field notes" — one paragraph, no title — when a single sentence is enough.

What is not here

• Model release commentary. There are ten better places for that.
• Vendor comparisons. This notebook is model-agnostic. If a pattern only works on one model, that's an anti-pattern.
• Sponsored content. There is no advertising, no affiliate link, no paid tier, no course.

Colophon

The site is a folder of static HTML files. No JavaScript framework. No analytics beyond aggregated server logs. Written in a plain text editor, published by rsync.