Silent model
Retired Grok slugs still resolve but redirect to other models, so the model served and the bill change silently
What changes
From May 15, 2026 12:00 PM PT, requests to the retired slugs redirect instead of erroring. grok-4-1-fast-reasoning, grok-4-fast-reasoning and grok-4-0709 go to grok-4.3 at low reasoning effort; grok-4-1-fast-non-reasoning, grok-4-fast-non-reasoning and grok-3 go to grok-4.3 at none; grok-code-fast-1 goes to grok-build-0.1; grok-imagine-image-pro goes to grok-imagine-image-quality, which is itself retired November 2, 2026. xAI says requests to a retired slug after May 15 are billed at grok-4.3 pricing ($1.25 per 1M input, $2.50 per 1M output).
Silent: No error. Behavior, results, or cost change quietly.
What to do
Set the model explicitly instead of relying on the redirect: grok-4.3 with an explicit reasoning_effort, grok-build-0.1 for code.
Strings to search for
grok-4-1-fast-reasoninggrok-4-1-fast-non-reasoninggrok-4-fast-reasoninggrok-4-fast-non-reasoninggrok-4-0709grok-code-fast-1grok-3grok-imagine-image-pro