Claude Fable 5 — Anthropic's most powerful model, a new tier above Opus — is now in the model picker ($10/$50 per MTok, 1M context). Opus 4.7 and 4.6 leave the picker (Opus 4.8 stays the default). Plus a real compatibility fix: temperature is no longer sent to models that reject it (Fable 5 / Opus 4.7+), which previously surfaced as an opaque 400.
Added
- Claude Fable 5 (
claude-fable-5) in the Anthropic provider — the most
powerful Claude model, a new tier above Opus. $10 input / $50 output per MTok, 1M context window. Pick it with /model claude-fable-5.
Changed
- Opus 4.7 and 4.6 removed from the model picker now that Opus 4.8 and
Fable 5 cover both tiers. The ids remain valid — if your config still points at one, it keeps working; it just isn't offered for new selection.
Fixed
temperatureis no longer sent to Anthropic models that reject it.
Fable 5 and Opus 4.7+ return HTTP 400 when the request includes temperature — and that 400 was previously masked by the tools-fallback retry, surfacing as a generic "API error". A model-aware guard (modelRejectsSamplingParams) now omits the parameter on those models across all three Anthropic request paths (agent, fallback, plain chat); omission means the API default, so behavior on other models is unchanged.