Unclear What 'alder_ford' is used for in practice, and what triggers the alias to be configured, isn't stated in the finding.
What
Claude Code can now read a config value keyed alder_ford from session config. If that value has an as alias and an ends_at expiry timestamp under 100000000000 (and hasn't expired) and the alias maps to a known model family, Claude Code substitutes that family's display name and cost info in place of the normal one.
The override is wired into cost lookup, managed-vs-list model detection, and the display-name lookup, but it does not apply to requests made with speed: "fast". It is also gated to first-party API usage only.
Why
This lets Claude Code present an alternate model's name and cost information for a limited, expiring window, useful for scenarios like testing or rollout of a model-family substitution without changing what model actually runs.
What 'alder_ford' is used for in practice, and what triggers the alias to be configured, isn't stated in the finding.