The tool inspects Bluesky profiles for signals that a reply account is automated rather than a human.

Simon Willison released a tool that examines any Bluesky profile for evidence of an automated reply bot. The checker reviews how fast an account replies, whether it ever posts original content, and whether it only answers users with large followings.

Willison has documented automated reply spam on Twitter for years, and he says the same pattern now appears on Bluesky. Bluesky still offers a free and usable API, which makes inspecting suspect accounts far easier than on platforms that locked access down. He wrote the tool with Opus 5.5.

Builders and trust teams can reuse the same detection signals to score reply accounts, triage spam, and measure how quickly a community degrades. The tool also shows what a small vibe-coded script can do when an open API gives developers real data.

Willison’s post arrives as automated replies spread across social platforms, and no platform has solved the problem. Watch whether Bluesky tightens API access, and whether other developers publish similar checks for bot accounts.

What matters

• Simon Willison built a checker that flags likely reply bots on Bluesky using the platform API.
• Bluesky keeps a free public API, so builders can inspect bot accounts without paid data access.
• Expect the same detection signals to spread as automated replies keep growing across social platforms.

Why it matters

Expect the same detection signals to spread as automated replies keep growing across social platforms.

This GenAI News article was prepared in original wording using reporting and materials published by Simon Willison’s Weblog. Source reference: https://simonwillison.net/2026/Sep/27/bluesky-bot-check/.

Drafted by the GenAI News review pipeline.