Anthropic released Claude Opus 5, a model the company says comes close to Claude Fable 5's capabilities in many domains while offering lower cost and fewer usage restrictions1.
Anthropic said Opus 5 is "much stronger at verifying its work and iterating carefully until it succeeds," citing benchmark testing in which the model wrote its own computer vision pipeline in response to an incomplete prompt. The company also said Opus 5 is "much better at complex coding tasks". Opus 5 outperforms Fable 5 on a number of benchmarks included in the announcement.
The release comes only two months after Opus 4.8, which became available on May 28. Anthropic's Mythos 5, Fable 5, and Sonnet 5 all launched in June, leaving only the lightweight Haiku model without a 5-series upgrade.
Opus 5 is not subject to the 30-day data retention policy that covers Fable and Mythos, a distinction that had raised concerns among privacy-conscious users of those models. ANALYSIS The absence of the retention policy, combined with lower pricing, positions Opus 5 as the default choice for enterprise and developer use cases where data handling is a sensitivity.
Opus 5's safeguards prevent it from being used to scan for vulnerabilities in a software binary, though it is permitted to search for vulnerabilities in source code — a distinction Anthropic draws because the latter task is more likely to be defensive in nature.
Fable 5 is the public-facing Mythos-class model that drew scrutiny from the U.S. government and was taken offline for a few weeks along with Mythos 5 before being brought back with stronger cyber safeguards. The Verge reported that Opus 5's launch follows weeks of negotiations between Anthropic and the U.S. government over Fable 5.
ANALYSIS By shipping a model that matches or exceeds Fable 5 on multiple benchmarks while carrying fewer restrictions and no data retention mandate, Anthropic effectively gives users a less encumbered path to near-frontier performance — sidestepping some of the friction that followed Fable 5's regulatory entanglement.
While Opus 5 is described as smaller than Fable 5, TechCrunch reported that the combination of lower cost and lighter restrictions will likely make it preferable in most use cases.