Simon Willison’s Weblog

--- +++ @@ -10,7 +10,7 @@ I was speaking about the advances in frontier models between November 2025 and February 2026, and I like to include at least one gimmick in my talks (a [STAR moment](https://simonwillison.net/2019/Dec/10/better-presentations/) - Something They'll Always Remember). In this case I decided the gimmick would be revealing at the end of the presentation that the slide mechanism itself was an example of what vibe coding could do. -I released the code [to GitHub](https://github.com/simonw/present) and then realized I didn't know anything about how it actually worked - I had prompted the whole thing into existence ([partial transcript here](https://gisthost.github.io/?bfbc338977ceb71e298e4d4d5ac7d63c) without paying any attention to the code it was writing. +I released the code [to GitHub](https://github.com/simonw/present) and then realized I didn't know anything about how it actually worked - I had prompted the whole thing into existence ([partial transcript here](https://gisthost.github.io/?bfbc338977ceb71e298e4d4d5ac7d63c)) without paying any attention to the code it was writing. So I fired up a new instance of Claude Code for web, pointed it at my repo and prompted: ````markdown-copy

--- +++ @@ -13,11 +13,11 @@ I released the code [to GitHub](https://github.com/simonw/present) and then realized I didn't know anything about how it actually worked - I had prompted the whole thing into existence ([partial transcript here](https://gisthost.github.io/?bfbc338977ceb71e298e4d4d5ac7d63c) without paying any attention to the code it was writing. So I fired up a new instance of Claude Code for web, pointed it at my repo and prompted: +````markdown-copy +Read the source and then plan a linear walkthrough of the code that explains how it all works in detail -> Read the source and then plan a linear walkthrough of the code that explains how it all works in detail +Then run “uvx showboat –help” to learn showboat - use showboat to create a walkthrough.md file in the repo and build the walkthrough in there, using showboat note for commentary and showboat exec plus sed or grep or cat or whatever you need to include snippets of code you are talking about -> +```` -> Then run “uvx showboat –help” to learn showboat - use showboat to create a walkthrough.md file in the repo and build the walkthrough in there, using showboat note for commentary and showboat exec plus sed or grep or cat or whatever you need to include snippets of code you are talking about - [Showboat](https://github.com/simonw/showboat) is a tool I built to help coding agents write documents that demonstrate their work. You can see the [showboat --help output here](https://github.com/simonw/showboat/blob/main/help.txt), which is designed to give the model everything it needs to know in order to use the tool. The `showboat note` command adds Markdown to the document. The `showboat exec` command accepts a shell command, executes it and then adds both the command and its output to the document.

--- +++ @@ -6,7 +6,7 @@ ## An example using Showboat and Present -I recently vibe coded a SwiftUI slide presentation app on my Mac using Claude Code and Opus 4.6. +I recently [vibe coded a SwiftUI slide presentation app](https://simonwillison.net/2026/Feb/25/present/) on my Mac using Claude Code and Opus 4.6. I was speaking about the advances in frontier models between November 2025 and February 2026, and I like to include at least one gimmick in my talks (a [STAR moment](https://simonwillison.net/2019/Dec/10/better-presentations/) - Something They'll Always Remember). In this case I decided the gimmick would be revealing at the end of the presentation that the slide mechanism itself was an example of what vibe coding could do.

--- +++ @@ -1,6 +1,6 @@ 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 work. +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.

--- +++ @@ -1,4 +1,4 @@ -Sometimes it's useful to have a coring agent give you a structured walkthrough of a codebase. +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 work.