Claude Opus 4.6 Fast
claude-opus-4-6-fastclaude-opus-4.6-fast- 🏢 Anthropic's speed-optimized variant of the Opus 4.6 reasoning model
- 📏 One-million-token context window for long sessions and codebases
- ⚡ Lower-latency "fast mode" trading some depth for speed
- 🧠 Adaptive thinking with selectable reasoning effort levels
- 👁️ Multimodal: text plus vision, with function calling and web search
- 🔧 Built for agentic coding, long-horizon tasks, context compaction
- 📚 Reported 90.2% on Anthropic's BigLaw Bench legal benchmark
- 🆕 Released April 2026, between Opus 4.5 and later 4.7/4.8 lines
Anthropic PBC is an American artificial intelligence company headquartered in San Francisco. Structured as a public benefit corporation, the lab develops large language models under the Claude name, with a research emphasis on building reliable, steerable, and safety-focused AI…
Explore 13 more models by Anthropic →Claude Opus 4.6 Fast is a latency-optimized configuration of Anthropic's Claude Opus 4.6, the top tier of the Claude family above the Sonnet and Haiku lines. It runs the same underlying model through a "fast mode" path, keeping the headline capabilities — a one-million-token context window (in beta), up to 128K output tokens, adaptive thinking, and context compaction — while targeting lower latency for interactive and agentic use. Capabilities here span reasoning, vision, code-optimized work, function calling, and web search.
Compared with its same-family predecessor Claude Opus 4.5, Anthropic positions Opus 4.6 as a meaningful step in long-context performance and deeper reasoning; partners noted it "thinks longer" and handles careful exploration like debugging better than Opus 4.5. On Anthropic's own BigLaw Bench it reportedly scored 90.2%, the highest of any Claude model at release, and the ARC Prize Foundation reported 94.00% on ARC-AGI-1.
The standard, full-quality version is Claude Opus 4.6; this Fast variant prioritizes responsiveness over maximum deliberation, so very hard reasoning tasks may still favor the full model.
Within the speed-optimized lineage, Opus 4.6 Fast is the earliest entry, later followed by Claude Opus 4.7 Fast and Claude Opus 4.8 Fast. Anthropic's documentation recommends the newer Opus generations for the most complex, long-horizon agentic work.
This About section is AI-generated from public sources via VeniceStats + Venice inference, with no human editing. It may contain inaccuracies.
| Seller | Reputation↓ | Routing | Input $/M | Cached $/M | Output $/M | Categories | API |
|---|---|---|---|---|---|---|---|
| Meridian AI 0x8c8c…06f5 | 5.64 | gated | $9.72 | $9.72 | $48.60 | chat,coding,reasoning | openai-chat-completions |
| antseed-neon-puma-944e 0x6650…944e | 0.00 | gated | $12.276 | $3.60 | $61.38 | chat,coding,math | openai-chat-completions |
| Leftermute 0x388b…5389 | 0.00 | gated | $7.272 | $7.272 | $36.36 | chat,coding,json,reasoning,tools | openai-chat-completions |
"Best price" and the seller table are live AntSeed catalog data (advertised $/1M tokens — or $ per generated image for unit-billed image models — not settled amounts). Reputation = on-chain trust (0-100). "Routing" = the SDK's default buyer routing (what the VPR desktop app ships with): a trust ≥ 60 gate on the effective reputation, then cheapest-first among routable sellers; live failover state (per-peer cooldowns) is buyer-side runtime and not included. Model knowledge (TLDR, provider, About) via the VeniceStats enrichment layer. Advertised catalog, not the model used in any specific purchase. "Usage on AntSeed" counts only settlements whose buyers share the per-model split on-chain (metadata v2/v3, opt-in), so every usage figure is a lower bound.