Simon Willison adds 'beats' content type to blog-to-newsletter tool using Claude Code agent

Simon Willison enhanced his blog-to-newsletter tool to incorporate a new content category called 'beats', which aggregates external posts like open-source project releases, tool builds, and museum visits from niche-museums.com. The modification was executed through a prompt to Claude Code, an AI coding agent, targeting the simonw/tools repository. Willison instructed the agent to clone the simonw/simonwillisonblog repository to /tmp for reference, ensuring it wouldn't be included in commits. The prompt directed updates to blog-to-newsletter.html to include beats with descriptions, mirroring the logic of the blog's Atom feed that filters out unannotated or draft beats. Validation involved running a Python HTTP server and using uvx rodney --help for browser automation to compare newsletter output with the homepage of simonwillison.net. The resulting pull request added a UNION clause to an SQL query, filtering drafts and beats lacking notes. This work is part of the guide 'Agentic Engineering Patterns', created and last modified on 18th April 2026. Willison's tool fetches content from a Datasette instance, formats it as rich text HTML for his Substack newsletter, which he uses to email subscribers his blog posts weekly.