When prefaced with "I am Claude", Kimi K3 prefers to generate API-specific Anthropic model identifiers, unlike other models Qwen, GPT, or even Claude itself. These exact identifiers appear in Claude API metadata, and are stripped out of Claude web chats.

While other models produce human-readable names like "Opus 4.5" or "Sonnet 4", Kimi K3 produces exact API model identifier like "claude-opus-4-5-20251101" or "claude-sonnet-4-20250514".

Which is extremely unusual. Web chats only contain the human-readable model name. Other models don't do this. So where did K3 get this data?

We can conclude, with high confidence, that:

1) K3 was trained on raw Claude API calls/metadata.

2) Claude API metadata was trained on in additional to standard web data.