It's not just Mercury 3. One of Inception's founding engineers confirmed on Discord [1] that they're shutting down API access to all Mercury models on December 28.

[1] https://s.strco.de/f/KYaU4Hg.png

Got the same email. A few days ago, I noticed that access via OpenRouter has vanished. Their approach was innovative; too bad it doesn't seem to have got traction.

phew. what a shame, this was a very good model for its specific use cases. what are you all planning to switch to once the API shuts down?

why? so weird. It was a fairly impressive model.