Server-driven model substitution, off unless configured / Claude Code v2.1.246

Use it now

Useful4 Signal4

Models Notable not in their notes

You can swap the model a request uses by setting an environment variable, or the server can do it.

CLAUDE_CODE_BREEZY_HORIZON

What

A new step can swap the model a request asks for before it is sent. The replacement comes from the environment variable CLAUDE_CODE_BREEZY_HORIZON, or failing that from a server-supplied config block that maps each source model to a replacement. With neither set, nothing changes, so this build only substitutes models if you set the variable or the server tells it to.

Details

A model id it does not recognise is logged and ignored rather than applied.
A real swap emits telemetry tengu_breezy_horizon recording the original model, the replacement, and whether the source was the environment variable or server config.

Evidence

[breezy_horizon] ${s}: ignoring unrecognized model id ${String(o)} for ${n}

Strings lifted out of the shipped bundle, so the claim above can be checked against them.