Anthropic has released Claude Opus 5, its new flagship model that the company says delivers performance close to its much pricier Fable 5 model at half the token cost.
The model is now the default on Claude Max and the most capable option available on Claude Pro. Anthropic is positioning Opus 5 as a response to pricing pressure from competitors including GPT-5.6 Sol and Chinese AI companies.
Pricing and Token Efficiency
Opus 5 keeps the same 1 million-token context window and token rates as its predecessor Opus 4.8. Input tokens cost $5 per million, output tokens run $25 per million. A new Fast Mode boosts speed by 2.5 times but doubles the price.
Token rates alone do not tell the full story because token efficiency varies by model. Opus 4.7 ended up costing 30 to 40 percent more per task than Opus 4.6 even though both had the same base rates. A similar pattern appeared with Claude Sonnet 5.
Users can adjust performance against token use through five effort settings: low, medium, high, xhigh, and max. Anthropic says Opus 5 offers better value than its predecessor at every effort level.
In its prompting guide, Anthropic recommends using the low and medium settings broadly. The company says these settings deliver good results with fewer tokens and lower latency while outperforming the same settings on earlier Opus models. For coding and agentic tasks, Anthropic still recommends starting with xhigh.
Opus 5 scores slightly worse at the max effort setting than at the second-highest setting on two benchmarks despite costing more. The drop appears on Frontier-Bench v0.1 and the Artificial Analysis Coding Agent Index.
Benchmark Performance
According to Anthropic's own benchmarks, Opus 5 sets records across several evaluations. On Frontier-Bench v0.1, the model hits 43.3 percent on agentic terminal coding. That beats Fable 5 at 33.7 percent, GPT-5.6 Sol at 34.4 percent, and Opus 4.8 at 21.1 percent by wide margins.
On the knowledge work benchmark GDPval-AA v2, Opus 5 leads with an Elo score of 1,861. Fable 5 scored 1,747 and GPT-5.6 Sol scored 1,736.
Opus 5 does not win everywhere. On agentic coding via DeepSWE v1.1, GPT-5.6 Sol leads with 72.7 percent, followed by Fable 5 at 69.7 percent and Opus 5 at 68.8 percent. On health tasks and legal benchmarks, Fable 5 and Mythos 5 outperform Opus 5 respectively.
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The ARC-AGI-3 result is likely the biggest surprise and outlier in Anthropic's benchmarks. The test measures novel problem-solving without relying on memorized patterns. Opus 5 scores 30.2 percent. Opus 4.8 managed just 1.5 percent and GPT-5.6 Sol hit 7.8 percent. That is nearly a four times gap over the next-best model. There is no Fable 5 result for this benchmark, and it is unclear whether such a large lead on a test will translate to real-world use.
Opus 5 falls behind Mythos 5 on cybersecurity tasks. Anthropic says it deliberately did not train Opus 5 on cyber tasks, as was the case with its predecessor. The model comes close to Mythos 5 at finding vulnerabilities but performs much worse when asked to exploit them.
Anthropic also says Opus 5 has improved at generating visual outputs and analyzing visual content such as charts and diagrams.
Self-Improvement and Tool Building
Anthropic describes Opus 5 as much better at checking its own work and improving it through iteration. In a Frontier-Bench task, Opus 5 received a drawing of a machine part and had to create a 3D model in FreeCAD. The catch was that the model intentionally had no way to view the drawing directly. Opus 5 responded by writing its own computer vision pipeline to extract the geometry from raw pixels, then reconstructed the complete machine part. No other model solved this task after five attempts, Anthropic says.
Opus 5 also worked on a real bug in a popular open-source package manager. According to Anthropic, it found the root cause and fixed an edge case that the community patch had missed. A competing model fixed only the surface symptom before reporting the bug as resolved.
An engineer at a trading firm reportedly used Opus 5 to build a market data feed for a new exchange in one session. Previous models could not complete the task, even with detailed plans.
Safety and Availability
Opus 5's safety setup allows source code vulnerability research but blocks binary-based vulnerability scanning, penetration testing, and exploit generation, according to Anthropic. The cyber classifiers trigger about 85 percent less often than on Fable 5. Fable 5's frequent interventions drew heavy criticism. Blocked requests in Claude.ai, Claude Code, and Claude Cowork default to Opus 4.8 as a fallback, the same approach used with Fable 5.
Anthropic calls Opus 5 the most capable generally available model for scientific research. It shows gains over Opus 4.8 across all life sciences evaluations, with standout improvements in organic chemistry (plus 10.2 percentage points on deriving molecular structures from spectroscopy data) and protein-related tasks (plus 7.7 percentage points).
Alongside Opus 5, Anthropic is releasing two beta features. Mid-Conversation Tool Changes on the Claude Platform let developers swap available tools during a conversation without invalidating the prompt cache. Automatic Fallbacks on the API route blocked requests to a different model automatically.