FIELD NOTES

What we learn taking broken AI systems apart.

Failure patterns, evaluation practice, and diagnostic method from engagements on LLM, RAG, NLP, and agent systems already running in production. Interviews, podcasts, and articles published elsewhere are collected here too.

Six September 2026 headlines announcing TypeSafe's Jev.
Field note

Jev and the no free lunch theorem

By John Licato

TypeSafe’s Jev returns an answer with a confidence score. On one task in an independent study it was at least 0.9 confident on 78% of items and wrong on 62% of them. Here are the numbers, including the ones in TypeSafe’s own cookbook.

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Field note

Your agent can't see most of a Word document

By John Licato

Microsoft Word keeps almost none of a document’s formatting next to the words, so an agent editing your document can’t see the styling it is breaking. Here is the routine I built to catch it, and how to install it.

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The first notes are being written. In the meantime, tell us what you're working on and we'll give you a senior technical read on the behavior you're seeing.