NoteSeptember 29, 2026 at 7:34 AM · 1 min read
Simon Willison builds a checker for Bluesky reply bots
Simon Willison has made a tool that checks Bluesky profiles for signs of automated reply bots. It looks for patterns such as rapid-fire replies and accounts that only respond to other users.
The tool examines a Bluesky profile for clues that an account may be a reply bot. It checks whether replies arrive within seconds of one another, and whether an account mainly replies to posts from more popular users instead of sharing its own content, images or links.
Willison says he used Opus 5.5 to build it. He says Bluesky’s public API makes it easier to investigate accounts than Twitter’s, where reply bots have also been a problem. The checker also looks for question marks, since Willison says some bots try to draw people into answering questions no person actually asked.
Why it matters
The tool gives Bluesky users a way to spot patterns that may help distinguish automated replies from genuine conversation.
Sources & references
| # | Source | Outlet | Date | Key takeaway |
|---|---|---|---|---|
| 1 | Bluesky reply bot checker ↗ | Simon Willison | Sep 27, 2026 | <p><strong>Tool:</strong> <a href="https://tools.simonwillison.net/bluesky-bot-check">Bluesky reply bot checker</a></p> <p>Automated reply |
1 sources
Last updated: September 29, 2026
Oossa · Newsletter
The week in AI, explained
Every Monday: the stories worth knowing, in plain language. Free, no spam.