Anthropic Claude Opus 5.5

DataCamp's head-to-head places Claude Opus 5.5 against OpenAI's same-day GPT-6 Sol release, contrasting an Anthropic pitch of Fable 5.1-level performance at lower run cost with OpenAI's mid-tier GPT-6 Sol launched at half the API price of GPT-5.6 Sol. The article confirms Opus 5.5 shipped on September 22, 2026 as Anthr The comparison concludes that Claude Opus 5.5 is the better choice for long-running agentic coding or for deployments that must run across all three major clouds, whereas GPT-6 Sol wins for cost-sensitive volume, Codex and ChatGPT Work teams, and budget business-app automation. DataCamp also reports that in a hands-on

CodeRabbit's review of Claude Opus 5.5 finds that the new model edges past its production baseline on bug coverage in an open-source test set and posts larger gains on a smaller, harder-curated set, but those gains come with more comments and higher reported token usage. The post documents five code-review-relevant cha For practitioners, the report advises starting at medium effort and benchmarking low and high alongside it, noting that the cost of a completed review still depends on the number of tokens and calls the model takes rather than headline rates. The team also stress-tested Opus 5.5 with an overnight coding project and vis

Anthropic launched Claude Opus 5.5 on September 22, 2026, as the first model in its Claude 5.5 family, pitching it as a cost-efficiency counter to rising pressure from OpenAI and open-weight rivals such as Nvidia Nemotron. According to Anthropic, Opus 5.5 performs at a Claude Fable 5.1 level but costs roughly 40% less Anthropic says Claude Opus 5.5 delivers more natural communication and clearer writing, and the company committed to rolling the same performance and efficiency gains into follow-on Claude Sonnet 5.5 and Claude Haiku 5.5 releases. The framing positions Opus 5.5 as the frontier option for use cases that justify higher s

Kingy AI's technical guide documents Claude Opus 5.5 as Anthropic's new flagship general-release model launched on September 22, 2026, priced at $4 input and $20 output per million tokens with $0.20 cache reads (20% cheaper than Opus 5 on base rates, 60% cheaper on cache reads, and 60% cheaper than Fable 5.1 and GPT-6 The guide flags Opus 5.5's API-breaking changes: thinking can no longer be turned off, forced tool choice is gone, the default effort level dropped from high to medium, and the computer-use tool type changed; specs are listed as 1M-token context, 128K max output, text and image input, and a June 2026 knowledge cutoff.

AWS announced that Claude Opus 5.5 is available on AWS, posting on its machine-learning blog on September 22, 2026 to mark the model's availability through AWS-hosted services for developers building on Anthropic's new Claude 5.5 family flagship. The post positions Opus 5.5 as the first Claude 5.5 family release and fr The blog entry serves as the AWS distribution channel for Anthropic's Claude Opus 5.5 release, mirroring the companion AWS what's-new announcement and confirming that customers can provision the new model through AWS's managed AI services alongside the broader Anthropic lineup.

Fello AI's September 2026 rankings report that Anthropic shipped Claude Opus 5.5 on September 22 and that Artificial Analysis's Intelligence Index v4.3.2 places it at 57.6, the highest score the index has ever published and 4.3 points clear of Claude Fable 5.1. Opus 5.5 also leads GDPval-AA v2.1, AA-Briefcase v1.1 and The same rankings page contextualizes Opus 5.5 inside the wider September 2026 frontier landscape, noting that OpenAI responded roughly ninety minutes later with GPT-6 Sol and GPT-6 Luna at half-price API rates, that GPT-6 Astra retains Arena coding boards because Opus 5.5 has no votes there yet, and that SpaceXAI ship