POST /v1/messages
{
"model": "claude-opus-4-7",
"speed": "fast"
}
→ error — fast mode was removed from Opus 4.7 on 2026-07-24
Fix:
Move to Opus 5 (claude-opus-5) or Opus 4.8 (claude-opus-4-8), which both still support fast mode. If you need to stay on Opus 4.7, drop the speed parameter — Opus 4.7 itself is still available at standard speed; only fast mode was withdrawn. In Claude Code, /fast now applies to Opus 5 and Opus 4.8 only.
Why this changed
Note the difference from the Opus 4.6 deprecation, because it is the thing that catches people: 4.6 fell back to standard speed, 4.7 does not. A request that previously degraded silently now fails outright, so code that relied on the fallback needs an explicit change rather than just tolerating slower responses.