Anthropic appears close to shipping Claude Opus 5, with signals pointing past internal testing into limited partner hands. A research entry surfaced briefly in a coding tool's model picker earlier this month before being pulled within hours, listed as an early access preview with per-turn controls, safety fallbacks, a one million token context window, and an extra-high-effort setting. A matching model string was then reported on Google's Vertex quotas catalog, echoing the sequence that preceded Sonnet 5. No pricing, system card, or public model identifier exists yet. Should it land, the model would appear in the Claude apps model selector for paid tiers, in Claude Code, on the Claude Platform, and across three cloud partners, most likely replacing Opus 4.8 rather than running beside it. The fallback detail—routing flagged prompts down to 4.8—hints the release is positioned nearer the frontier. Sonnet 5 arrived at the end of June performing close to 4.8 at a fraction of the cost, while Fable and Mythos sit above it. Subscription-inclusive Fable 5 access ended on 19 July with usage credits taking over. Cadence supports the guess: 70 days from 4.6 to 4.7, 42 from 4.7 to 4.8, and 56 so far since. Expectations run toward a clear step up on coding work. Anthropic has said nothing.