Simon Willison

Panache — RTS Belle Époque pour mobile

Panache is a real‑time strategy game for mobile and browser set in France’s Belle Époque around 1900, featuring steampunk elements such as dirigibles, steam‑powered trucks, armored ships, and marching fortresses. The game was released under an Apache 2.0 license and already has a French‑language fork that reskins it to a steampunk 1900s France, adding an animated intro and French‑twisted music. The updates are mainly aesthetic, with new models and an intro video showcased on the game’s page.

Simon Willison
Oct 22

DE STAAT - FREEDOM (Official Music Video)

The article announces the release of the official music video for "DE STAAT - FREEDOM" by Dutch alternative rock band De Staat. It notes that at 00:44 in the video, visual effects are credited to Matties Grooten of Fake it or Leave it. The post also mentions the video’s presence on Hacker News and tags it with music, AI, generative‑AI, and pelican‑riding‑a‑bicycle.

Simon Willison
Sep 26

Kākāpō Party

Simon Willison presented a closing keynote at the WeAreDevelopers World Congress North America, where he showcased a pixel‑art animation of kakapo parrots celebrating a record‑breaking breeding season in 2026. He used Claude Opus 5.5 to generate the animation from Google‑searched kakapo photos, then employed Claude Code with Playwright to record a 15‑second video of the animated HTML5 canvas, which he embedded in his Keynote slide.

Simon Willison
Oct 20

Battle Drones - a vibe coded RTS with audio-based multiplayer

Battle Drones is a browser‑based, Command & Conquer‑style real‑time strategy game that evolved through 12 major iterations, adding 3D models, varied terrain, random map generation, and both local and online multiplayer via audio synchronization. The game features nine buildings, seven ground vehicles, six aerial vehicles, and three infantry units, with fog of war, area‑effect weapons, and multiple play modes such as skirmish and last‑stand. The project showcases how AI‑assisted coding (primarily Claude) can accelerate game development and introduce innovative multiplayer mechanics using sound.

Simon Willison
Oct 28

The October inflection point for vibe game development

Simon Willison discusses a new inflection point in October 2026 for creating video games using AI, noting that Claude Opus 5.5 now reliably produces compelling 3D models, music, and especially game design. He reports having successfully "vibe coded" four enjoyable games without inspecting the code, and highlights that the real challenge is now generating novel, delightful concepts that AI alone could not conceive. The author compares Opus 5.5’s fun factor to GPT‑6 Astra, which he finds lacking in that regard.

Simon Willison
Sep 18

Quoting Thariq Shihipar

The article announces that Claude Code will now support AGENTS.md files starting with version 2.1.277. If a CLAUDE.md file is absent in a folder, Claude will automatically look for and use AGENTS.md, leveraging Claude Code mods to customize the harness. The built‑in mod is available for use, and users can also create their own custom project instructions.

Simon Willison
Oct 14

Tree Appreciator

Simon Willison describes a game experiment called "Tree Appreciator" created with Claude Opus 5.5 Max. The game, built in three.js, presents two algorithmically generated trees and challenges players to appreciate their differences through a spot‑the‑difference style mechanic. After three hours and seven minutes of processing, Claude produced a polished, music‑and‑animation‑rich game with achievements that feels both fun and beautiful.

Simon Willison
Sep 9

.blend URL Viewer

Simon Willison created a .blend URL Viewer tool that lets users view a Blender model of a Fabergé egg themed after the TV show Pluribus directly in their browser. He generated the egg image using ChatGPT Images 2.5, then fed it to GPT‑6 Astra with a custom Blender skill to produce several .blend files. The viewer, built with JavaScript, is now part of his tools collection for easy access to the resulting 3D model.

Simon Willison
Sep 16

Claude Cowork and chat are now one Claude

Claude Cowork and the standard chat interface are merging into a single Claude experience, allowing users to hand over tasks or ask quick questions that the system will continue to handle even after the laptop is closed. The rollout will begin with Pro and Max plan users across web, desktop, and mobile, and will extend to new users on these plans over the coming weeks. This integration suggests Claude is evolving into a general agent, simplifying the distinction between Cowork and regular Claude usage.

Simon Willison
Oct 6

Scrimshaw Jukebox

Simon Willison experimented with Claude Opus 5.5 to compose computer game music, specifically aiming for a style reminiscent of the original *Secret of Monkey Island*. He designed a simple text-based format for the music and built an artifact capable of playing it, including example tracks. The results were surprisingly good, prompting questions about whether this compositional ability is a new capability emerging in recent text models.

Simon Willison
Sep 2

Claude's new system prompt really doesn't want to reproduce song lyrics

Anthropic has released the system prompts for its Claude consumer applications, including historic changes and an index structure that allows easy diffing of prompts. The latest update, seen in Fable 5.1, adds a comprehensive rule that Claude will not reproduce song lyrics, poems, or copyrighted passages, and will refuse any reworded requests thereafter, offering analysis instead. The prompts are accessible in Markdown via the platform.claude.com/docs site, facilitating transparent tracking of policy changes.

Simon Willison
Sep 5

Introducing GPT-6 Astra for developers

Simon Willison introduces GPT‑6 Astra, a new model that offers improved attention to detail, better prompt comprehension, and the ability to generate more sophisticated outputs. The model excels at creating 3D renderings, producing detailed scenes such as gardens, shipyards, animals, cityscapes, and even Dyson spheres. Willison highlights its whimsical creativity, noting examples like a pelican wearing a red neckerchief riding a bicycle.

Simon Willison
Aug 23

Quoting Drew Breunig

The article reflects on the shift in perspective after the release of Fable, a new model that promised to solve many coding challenges at a comparable or lower cost. Prior to Fable, developers felt it was pointless to invest heavily in coding tools or context strategies, as newer models would likely render them obsolete. However, Fable’s performance was so impressive that, despite its high cost, it prompted a reevaluation of how work was distributed across different models such as Opus, 5.6, K3, and GLM.