Claude Sonnet 5.5
claude-sonnet-5-5Claude-Sonnet-5-5claude-sonnet-5.5sonnet-5-5sonnet-5.5- 🆕 Anthropic's Sonnet-class upgrade, released September 2026, succeeding Sonnet 5.
- 📏 1M-token context window with up to 128K output tokens.
- 🧠 Adaptive thinking with selectable effort levels for depth-versus-latency tradeoffs.
- 🔧 Tuned for well-scoped work: features, bug fixes, documents, slides, spreadsheets.
- 👁️ Vision and document understanding, function calling, and web search.
- ⚡ Positioned as the faster, lower-cost complement to Opus 5.5.
- 💬 Anthropic says it writes and communicates more clearly than Sonnet 5.
- 🔒 Behavioral audit: matches or improves on Sonnet 5 across most measures.
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 16 more models by Anthropic →Claude Sonnet 5.5 is Anthropic's mid-tier Claude model, released in September 2026 as the direct successor to Claude Sonnet 5. In Anthropic's own framing, it is the faster, lower-cost complement to Claude Opus 5.5: where the Opus tier targets complex work requiring careful judgment, Sonnet 5.5 is aimed at well-scoped everyday tasks such as building features, fixing bugs, and producing polished documents, slides, and spreadsheets.
Structurally it carries forward the Sonnet 5 platform profile — a 1M-token context window that is both default and maximum, 128K maximum output tokens, adaptive thinking, and text, image, and file inputs. Capability-wise the catalog lists reasoning, vision, code optimization, function calling, and web search, so integrators moving from Sonnet 5 largely keep the same tool and feature surface. Anthropic's documentation now describes Sonnet 5.5 as the current Sonnet model and recommends migrating from Sonnet 5 for improved performance.
On generational gains, Anthropic reports that on Terminal-Bench 4.0 — a benchmark for multi-step professional tasks in a command line — Sonnet 5.5 at Medium effort (the default in the Claude apps) exceeds Sonnet 5's best score at a small fraction of the cost per task. Anthropic also says the model communicates and writes more clearly than its predecessor, a change echoed in platform listings.
On safety, Anthropic's automated behavioral audit of roughly 1,850 scenarios found Sonnet 5.5 improves on or matches Sonnet 5 on most measures of alignment, misuse resistance, and honesty, and performs strongly on newer containment evaluations, with Opus 5.5 still slightly ahead overall.
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 |
|---|---|---|---|---|---|---|---|
| ▲ Apex Ant 0x73b4…e736 | 71.90 | #2 | $1.52 | $0.15 | $7.60 | chat,reasoning,coding,vision,multimodal,long-context,agents,tasks,legal,study,translate | openai-chat-completions |
| Venice.ai Proxy 0x1f22…18c9 | 70.55 | #4 | $1.875 | $0.1875 | $9.375 | chat,reasoning,coding,vision,multimodal,web-search | openai-chat-completions |
| D5V1N2 0xd5e7…7be0 | 67.45 | #5 | $3.60 | $0.40 | $18.00 | chat,coding,agent,reasoning,vision,large-context,frontier,claude,router,fallback | openai-chat-completions |
| GesundAI 0x983e…d826 | 66.98 | #1 | $0.30 | $0.20 | $0.80 | chat,code,fast,vision,multimodal | anthropic-messages |
| Super Seeder 0xd19f…41f3 | 63.77 | #3 | $1.8563 | $0.1856 | $9.2813 | chat,coding,reasoning,vision,multimodal,tools,long-context | openai-chat-completions |
| Edith AI 0xb269…b1a6 | 61.93 | gated | $1.60 | $1.60 | $8.00 | chat,coding,reasoning,fast | openai-chat-completions |
| ZLKPro-Api 0x0b0b…f446 | 58.35 | gated | $0.55 | $0.10 | $3.00 | agent,chat,text,reasoning,research,smart,long-context,multimodal,vision | openai-chat-completions |
| bartly.eth64.de 0x666e…4666 | 53.43 | gated | $3.38 | $3.38 | $16.88 | chat,coding,reasoning,vision,multimodal,tools,long-context,web-search,function-calling | openai-chat-completions |
| Fire Ant 🔥🐜 0xbe05…bc5d | 50.00 | gated | $3.0656 | $0.3066 | $15.328 | chat,coding,reasoning,tools | — |
| Hana Gateway ✅ 0x4ae1…117b | 45.41 | gated | $0.20 | $0.04 | $1.20 | chat,coding,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 = buyer trust score (0-100, the AntSeed SDK's own formula). "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.