Simon Willison’s Weblog

Support for branches other than the default branch. Use uvx commit-rewriter --branch other to run against another branch. #3

I presented a closing keynote for the WeAreDevelopers World Congress North America yesterday. As a STAR moment I decided to weave in references to the record breaking kākāpō breeding season we had in 2026.

For my closing slide I wanted to celebrate, and I had seen some buzz around how good Claude Opus 5.5 was at creating pixel art animations. So I rounded up three Kakapo photos from Google image search and dropped them into Claude with this prompt:

Here are some photos of kakapo parrots just to remind you what they look like

I need you to make an animation in animated pixel art on HTML 5 canvas of obviously pixel art kakapo jumping up and down having a party with confetti and suchlike - there should be at least 20 of them

Here's the transcript, and this is the resulting page. It's pretty great!

I wanted to embed it in a Keynote presentation file, so I downloaded the HTML and told a local Claude Code session:

Make me a video of file:///Users/simon/Downloads/kakapo-party.html - you need to load it in a browser and click on it a few times to get the confetti effect, the video should be 15s long

don't start clicking until 3s in

make sure several clicks are spread around the clickable area

Claude Code used Playwright (transcript here) and produced this video, which was exactly what I needed for my final slide:

Here's the full Playwright script it used, which was pleasingly short:

# /// script
# dependencies = ["playwright"]
# ///
import time
from playwright.sync_api import sync_playwright
W, H = 1280, 720
# Canvas fills the viewport; spread clicks across corners, edges and centre
clicks = [
    (3.0, 640, 360),   # centre
    (4.2, 160, 120),   # top-left
    (5.4, 1120, 120),  # top-right
    (6.6, 180, 600),   # bottom-left
    (7.8, 1100, 600),  # bottom-right
    (9.0, 640, 100),   # top-centre
    (10.0, 380, 380),  # mid-left
    (11.0, 900, 380),  # mid-right
    (12.2, 640, 620),  # bottom-centre
    (13.2, 640, 300),  # finale centre
]
with sync_playwright() as p:
    b = p.chromium.launch()
    ctx = b.new_context(viewport={"width":W,"height":H}, record_video_dir="vids", record_video_size={"width":W,"height":H})
    page = ctx.new_page()
    t0 = time.time()
    page.goto("file:///Users/simon/Downloads/kakapo-party.html")
    for t,x,y in clicks:
        time.sleep(max(0, t-(time.time()-t0)))
        page.mouse.click(x,y)
    time.sleep(max(0, 16.0-(time.time()-t0)))
    ctx.close(); b.close()

Automated reply bots on Twitter are a scourge - as someone with a decent number of followers I attract a swarm of these, such that anything I post there attracts dozens of mindless automated replies.

They've started manifesting on Bluesky as well.

Unlike Twitter, Bluesky still has a freely available and useful API. The lack of such a thing doesn't slow down the bots, but it does make investigating them a lot more frustrating.

So I had Opus 5.5 vibe code this tool, which examines any Bluesky profile for evidence of a likely reply bot.

It looks for signals like replies posted within seconds of other posts from the same account, or accounts that never post their own content (or images or links) but instead consistently reply to messages from other, higher-follower users.

It also looks for question marks, because I'm extra infuriated by reply bots that trick me into wasting my time answering a question that no human ever posed.

I took a photograph of some protesters, then thought about how I don't like sharing photographs of strangers with identifiable faces. I had GPT-6 Astra build this experimental tool that would identify faces and automatically blur them out.

It uses Google's MediaPipe C++ library, compiled to WebAssembly via @mediapipe/tasks-vision, plus the BlazeFace face detection model.