Simon Willison’s Weblog

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Wednesday, 25th February 2026

Agentic Engineering Patterns >

Linear walkthroughs

Sometimes it's useful to have a coding agent give you a structured walkthrough of a codebase.

Maybe it's existing code you need to get up to speed on, maybe it's your own code that you've forgotten the details of, or maybe you vibe coded the whole thing and need to understand how it actually works.

Frontier models with the right agent harness can construct a detailed walkthrough to help you understand how code works. [... 525 words]

# 1:07 am / agentic-engineering, ai, llms, vibe-coding, coding-agents, ai-assisted-programming, swift, generative-ai, showboat

It’s also reasonable for people who entered technology in the last couple of decades because it was good job, or because they enjoyed coding to look at this moment with a real feeling of loss. That feeling of loss though can be hard to understand emotionally for people my age who entered tech because we were addicted to feeling of agency it gave us. The web was objectively awful as a technology, and genuinely amazing, and nobody got into it because programming in Perl was somehow aesthetically delightful.

Kellan Elliott-McCrea, Code has always been the easy part

# 3:30 am / kellan-elliott-mccrea, perl, ai, generative-ai, llms, agentic-engineering, deep-blue

Tuesday, 24th February 2026