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Here's the table of contents for my lengthy new piece on how I use LLMs to help me write code simonwillison.net/2025/Mar/11/...

Víctor García

@gc-victor.bsky.social

12 Mar 2025

I'm surprised that you aren't using system prompts

Simon Willison

@simonwillison.net

I use custom instructions in Claude projects for a few things simonwillison.net/2024/Dec/19/...

simonwillison.netBuilding Python tools with a one-shot prompt using uv run and Claude ProjectsI’ve written a lot about how I’ve been using Claude to build one-shot HTML+JavaScript applications via Claude Artifacts. I recently started using a similar pattern to create one-shot Python utilities,...

12/3/25, 4:50 am0 reposts3 likes

Víctor García

@gc-victor.bsky.social

12 Mar 2025

Oh, great! And have you tried more general system prompts to guide the conversation and output in a structured way? Like returning as output a diff, like what some code assistants do

Simon Willison

@simonwillison.net

12 Mar 2025

I've been exploring dedicated JSON schema features from different models recently, they mostly work really well simonwillison.net/2025/Feb/28/...

simonwillison.netStructured data extraction from unstructured content using LLM schemasLLM 0.23 is out today, and the signature feature is support for schemas—a new way of providing structured output from a model that matches a specification provided by the user. …