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Anthropic prices Claude Opus 4.5 at $5/1M input and $25/1M output tokens, much cheaper than Opus 4.1 at $15/$75 but still pricier than GPT-5.1 and Gemini 3 Pro

Opus 4.5 was responsible for most of the work across 20 commits, 39 files changed, 2,022 additions and 1,173 deletions in a two day period. … Forums: r/BetterOffline : Claude Opus 4.5, and why evaluating new LLMs is increasingly difficult

Simon Willison's Weblog Simon Willison

Discussion

  • @jerhadf Jeremy on x
    one fact people won't realize immediately about opus 4.5: it's remarkably token-efficient. all-in it's often *cheaper* than sonnet 4.5 and other models for cost-per-task-success. glad sourcegraph is seeing this early in Amp! we find that opus 4.5 with medium effort is pareto [ima…
  • @zephyr_z9 @zephyr_z9 on x
    So how did they achieve this I doubt they cut margins Is it something like DSA or is it fp4 finesse?? @teortaxesTex
  • @teortaxestex @teortaxestex on x
    > cache hits 0.5$ ok Anthropic is NOT dead
  • @johnonolan John O'Nolan on x
    goodbye Gemini3 - I enjoyed our weekend together
  • @mattshumer_ Matt Shumer on x
    We need a new way to express AI costs... $/token doesn't make much sense anymore. Maybe a benchmark that tries to give a sense of the cost to run an average workload?
  • @theo @theo on x
    Anthropic lowered the price on Opus 4.5? They might have actually cooked here
  • @sqs Quinn Slack on x
    Opus is worth it, and maybe cheaper all-in than Sonnet? Early rough non-representative numbers, for our own internal @AmpCode usage (avg cost $ per thread): - Sonnet 4.5: $1.83 - Opus 4.5: $1.30 (earlier checkpoint last week was $1.55) - Gemini 3 Pro: $1.21
  • @thezvi Zvi Mowshowitz on x
    They're burying a lot here. There's a 66% price cut from Opus 4.1 to $5/$25, it uses fewer tokens to solve problems, upgrades to Claude Code in the app, no more length limits on conversations, no more Opus-specific plan caps...
  • @alexalbert__ Alex Albert on x
    It's also dramatically more efficient. On SWE-bench Verified at medium effort, Opus 4.5 beats Sonnet 4.5 while using 76% fewer output tokens. The new effort parameter lets you trade off intelligence for cost/latency with a single dial. [image]
  • @scaling01 @scaling01 on x
    CLAUDE 4.5 OPUS PRICING $5 / $25 THEY DID IT [image]
  • @simonw Simon Willison on x
    Updated my post with this section about their improved protection against prompt injection attacks - definitely better, but the problem is that if an attacker gets 10 tries they'll still succeed 1/3rd of the time! https://simonwillison.net/... [image]
  • @jeffwsurf Jeff Wang on x
    Opus models have always been “the real SOTA” but have been cost prohibitive in the past. Claude Opus 4.5 is now at a price point where it can be your go-to model for most tasks. It's the clear winner and exhibits the best frontier task planning and tool calling we've seen yet.
  • r/BetterOffline r on reddit
    Claude Opus 4.5, and why evaluating new LLMs is increasingly difficult