Anthropic is out in the open again: Two mysterious Claude models revealed

Dynamic Beating AI News Flash: Anthropic has two more early access versions of the Claude model discovered by developers, codenamed claude-marshmallow-eap (Marshmallow) and claude-melon-eap (Melon).

Testers reported that Marshmallow outperformed Melon overall, but neither has yet reached the level of Fable 5. Some testers also found Marshmallow's conversational experience superior to Opus 5.

This is not the first time an internal code name following a food name + EAP pattern has appeared. In early July, the Claude Honeycomb EAP (Honeycomb) briefly surfaced on Cursor before being taken down; on July 24, Anthropic officially released Opus 5. While Anthropic never confirmed that Honeycomb was Opus 5, there have indeed been EAP models appearing prior to the official launch of new products.