Anthropic released Claude Opus 5 on July 24, priced at $5 per million input tokens—half the cost of its predecessor model Claude Fable 5—while outperforming Fable 5 on most major benchmarks. Opus 5 scored 43.3% on Frontier-Bench v0.1, an agentic coding evaluation, versus 33.7% for Fable 5 and 34.4% for OpenAI's GPT-5.6 Sol; on ARC-AGI-3, a novel problem-solving benchmark, it scored 30.2% against GPT-5.6 Sol's 7.8%. The new model became the default on Claude Max and the strongest option on Claude Pro, effectively replacing Fable 5 as the go-to for most subscribers following Fable 5's operational disruptions earlier this summer.
Anthropic's lineup runs four tiers: Haiku is fast and cheap, Sonnet is mid-range, Opus is the heavy workhorse, and the Mythos class—introduced this spring—includes Claude Fable 5 for the public and Claude Mythos 5 for vetted cybersecurity researchers and critical infrastructure operators through Project Glasswing.
Claude Opus 5 Outperforms Fable 5 Across Major Benchmarks
On Frontier-Bench v0.1, which tests whether AI coding agents can complete real software engineering tasks end-to-end, Opus 5 hit 43.3%. Fable 5 came in at 33.7%, and OpenAI's GPT-5.6 Sol scored 34.4%.
The widest margin appeared on ARC-AGI-3, a test of problem-solving built around novel puzzles a model could not have memorized from training data. Opus 5 hit 30.2%; GPT-5.6 Sol scored 7.8%; Fable 5 was not tested at all.
On GDPval-AA v2, a knowledge work benchmark scored via Elo ratings used to measure relative performance on real professional tasks, Opus 5 reached 1,861 against Fable 5's 1,747 and GPT-5.6 Sol's 1,736.
Fable 5 outperformed Opus 5 by a small margin only in legal and health-related evaluations, according to Anthropic's published benchmarks.
Anthropic Prices Opus 5 at $5 Per Million Input Tokens
Opus 5 is available via API at $5 per million input tokens and $25 per million output tokens. A Fast mode running at roughly 2.5 times the default speed is available at twice the base price—$10 per million input tokens and $50 per million output tokens.
The pricing matches Opus 4.8 and is exactly half the cost of Fable 5, which Anthropic had positioned as the everyday frontier product for paying users.
Fable 5 Pulled Globally After Export Control Order
Fable 5 launched June 9, was pulled globally three days later after the U.S. government issued an emergency export control order citing a jailbreak vulnerability, and came back June 30. Upon return, it shifted immediately to a credits-only model, no longer included in standard plans.
Opus 5 now fills the slot Fable 5 could not hold as the subscriber flagship.
Third-Party Platforms Validate Opus 5 Performance Gains
Lovable, a developer platform with millions of users, ran Opus 5 on its internal evaluations. "It isn't just better on our hardest agentic coding tasks, up 22% over Opus 4.7, it's steadier, with far less variance run to run," Fabian Hedin said in a statement shared by Anthropic.
Zapier tested Opus 5 on AutomationBench, an evaluation that scores whether a model can carry a full business workflow from start to finish without human help. The model "took a raw account-health workbook and ran a full churn-prevention sequence end to end: flagging at-risk accounts, alerting the right owner, and summarizing for retention ops. Previous models didn't pass; Opus 5 hit 100%."
Ultima Genomics, a DNA sequencing company, said the model "behaves more like a careful scientist than any model we've run. It reaches for the right statistical tests to rule out confounders, cross-checks its own results by independent methods, and stays on track through long multi-step analyses."
The release landed a week after Moonshot AI, a Beijing-based startup backed by Alibaba, unveiled Kimi K3—a 2.8-trillion-parameter open-weight model that Moonshot described as the world's largest open AI system. Independent benchmarks consistently placed Kimi K3 third overall, behind both Fable 5 and GPT-5.6 Sol, beating those two in specific areas.
FAQ
What benchmarks did Claude Opus 5 outperform Fable 5 on?
Claude Opus 5 scored 43.3% on Frontier-Bench v0.1 versus Fable 5's 33.7%, 30.2% on ARC-AGI-3 (Fable 5 was not tested), and 1,861 on GDPval-AA v2 versus Fable 5's 1,747. Fable 5 outperformed Opus 5 by a small margin only in legal and health-related evaluations.
How much does Claude Opus 5 cost compared to Fable 5?
Claude Opus 5 costs $5 per million input tokens and $25 per million output tokens via API—exactly half the implied cost of Fable 5. A Fast mode is available at $10 per million input tokens and $50 per million output tokens.
Why was Claude Fable 5 pulled from global availability?
Fable 5 launched June 9 and was pulled globally three days later after the U.S. government issued an emergency export control order citing a jailbreak vulnerability. It returned June 30 as a credits-only model, no longer included in standard plans.
