Anthropic's Opus-tier Claude model, built for long-running agentic coding and knowledge work. It replaced Opus 5 at a lower $4 / $20 rate with the same 1M-token context, and sits between Sonnet 5.5 and Fable 5.1.
Pick it if
you want Opus-tier Claude at 20% below Opus 5's per-token rates
you resend long prompts; cache hits bill at 5% of input
you run long agentic coding sessions across a 1M-token window
Skip it if
Sonnet 5.5 at half the per-token price covers your workload
your code forces tool use or turns thinking off; both are unsupported
Anthropic's mid-tier Claude model, which Anthropic describes as its best combination of speed and intelligence. It succeeds Sonnet 5 at the same $2 / $10 rate, with a 1M-token context and half the cache-read price, and sits below Opus 5.5.
Pick it if
you want Claude at half of Opus 5.5's per-token price
you resend long prompts; cache hits bill at 5% of input
your prompts need a 1M-token window at the standard rate
Skip it if
Haiku 5.5 handles your high-volume classification or routing more cheaply
your code forces tool use or sets temperature; both return errors
FAQ
Which is better, Claude Opus 5.5 or Claude Sonnet 5.5?
On Terminal-Bench 4.0, as each maker reports it, Claude Opus 5.5 scores 66.4% and Claude Sonnet 5.5 70.6%. These are each maker's own numbers, not a controlled head-to-head; the spec table lists every benchmark both publish.
Which is cheaper, Claude Opus 5.5 or Claude Sonnet 5.5?
Claude Sonnet 5.5 lists lower input and output prices. On a coding-agent session (2M tokens in, 60,000 out) Claude Opus 5.5 costs $9.20 and Claude Sonnet 5.5 $4.60.
Can I switch between Claude Opus 5.5 and Claude Sonnet 5.5 mid-task?
Yes. In an Octomind session, /model octohub:claude-opus-5-5 and /model octohub:claude-sonnet-5-5 switch models without losing the conversation, so you can draft on one and review on the other.
Try either model
Switch between models inside the same Octomind session.