Claude Opus 5.5 & Opus 5: the flagship experience, for less.

On July 24, 2026, Anthropic released Claude Opus 5 — and quietly rearranged what you get on every paid Claude plan. It replaces Opus 4.8, becomes the default model on Claude Max, and is now the strongest model on Claude Pro. Anthropic's pitch: intelligence close to its Fable 5 flagship, at half the API price. Here’s what actually changed, and what to do about it.

New September 22, 2026: Opus 5.5 arrives

Two months after this lesson first ran, Anthropic shipped Claude Opus 5.5 — the first model in a new Claude 5.5 family. Anthropic’s one-line pitch: it performs at the level of Fable 5.1 on most work and costs 40% less to run than Opus 5. Everything below about the effort dial and picking the right model still applies; the Opus slot just got a much stronger engine.

• API price: claude-opus-5-5 at $4 in / $20 out per million tokens (Opus 5: $5 / $25). Cache reads fall to $0.20 (from $0.50), batch is half price at $2 / $10, and Fast mode runs up to 2.5× quicker at $8 / $40. The “40% cheaper” figure is per task: lower prices plus fewer tokens used.
• Where it runs: Anthropic says it is available on all platforms — the Claude apps, Claude Code, the API, and Amazon, Google Cloud and Microsoft Foundry.
• For subscribers: Anthropic is raising five-hour usage limits on Pro, Max, Team and seat-based Enterprise plans, and giving subscribers a one-off limit reset to save and spend when you choose: Settings → Usage → “Reset for free”, on the web or Claude Desktop (not mobile). Once used it can’t be undone, and an unused one can expire — the date shows in Settings.
• Writing: Anthropic says it puts the important point first and uses less jargon — the most common complaint about Opus 5.
• Safety routing: it is the first Opus to ship with Fable-class safeguards for cybersecurity and biology. Routine bug-fixing is fine, but most cybersecurity tasks get re-routed to Opus 4.8 — so security folk will see more “answered by a different model” notices than on Opus 5.

What changes in practice: the section 05 advice — Opus for daily work, Fable for the last few percent — tilts further toward Opus. Next time you’d reach for Fable, try Opus 5.5 first; on plans where Fable draws on usage credits, that can be real money saved. The full decision framework is in which Claude for which job, and the per-token maths in what Claude actually costs.

01 Where it lands in the lineup

Anthropic's model family now reads like this: Fable 5 stays the most intelligent generally available model. Opus 5 sits just below it — Anthropic's own charts show it within a whisker of Fable 5 on several coding benchmarks — at half the price and built for everyday use. Sonnet 5 remains the fast free-tier default, and Haiku handles the lightweight jobs.

02 The effort dial

Opus 5 exposes an effort setting: how hard the model works before it answers. Crank it up for a gnarly analysis; keep it low for routine tasks and it answers faster while spending fewer tokens. Anthropic claims that even at the lowest effort, Opus 5 passes more tasks than any other model on Zapier's business-automation benchmark — which is the real story here: the floor got high.

The practical habit: stop treating "the best model" as one fixed thing. On hard problems, high-effort Opus 5 is a near-Fable experience. On everything else, low effort gets you a fast, cheap answer from the same brain.

03 It checks its own work

The through-line in early reports is verification behavior: Opus 5 opens its own web pages to catch layout bugs, builds test harnesses when none exist, and pushes back (politely, with reasons) when your design idea has a flaw. In one of Anthropic's examples, the model was asked to rebuild a machine part from a drawing it couldn't view — so it wrote its own computer-vision pipeline to read the pixels, then built the part. That thoroughness is what "agentic" is supposed to mean, and it's why this release matters beyond benchmark charts.

04 The safety plumbing moved too

Two routing changes worth knowing if you've followed our Fable 5 lessons:

• Biology questions: requests blocked by Fable 5's safety classifiers now route to Opus 5 (previously Opus 4.8) — so the fallback answers got smarter.
• Cybersecurity: Opus 5's own cyber classifiers are lighter-touch than Fable's (Anthropic expects ~85% fewer interventions), but flagged requests in the Claude apps still fall back to Opus 4.8.

05 Opus 5 or Fable 5?

• Default to Opus 5 for daily work: drafting, analysis, coding, agents, long documents. Near-flagship quality, faster and cheaper.
• Reach for Fable 5 when the last few percent of reasoning matters — the hardest strategy, research, or debugging problems.
• Let Sonnet 5 keep the small stuff. Quick questions don't need a heavyweight.

One honest caveat: the benchmark numbers above are Anthropic's own, published on launch day. Independent results will trickle in over the coming weeks — the pattern with Sonnet 5 and Fable 5 was that the headline claims held up directionally, with some gaps narrower than advertised.