Anthropic launched Claude Opus 5 on July 24. It is now the default model on Claude Max and can also be selected on Pro. The Claude API, Amazon Bedrock, Google Cloud, and Microsoft Foundry began offering it the same day.

Opus 5's API prices are lower than Fable 5's. Its input and output token rates are both half Fable 5's, but that does not mean every task will cost half as much. Opus 5 edged ahead in the first external evaluations, while early user reports pointed in different directions.

Available Right Away on Max, Pro, and the API

Opus 5 was available to all Claude API customers from launch day. The existing Opus 4.8 remains available, so customers can continue to choose between the two models.

On July 25, a direct check in Korea found Opus 5 in the model menus on claude.ai and Claude Code and confirmed that API calls through OpenRouter were working. These observations were made the day after launch; they did not come from Anthropic's documentation.

The model accepts up to one million tokens in a single request. The limit applies by default, with no separate setting to enable it, and cannot be raised further. Opus 5 can generate up to 128,000 output tokens, and thinking is enabled by default.

Lower Token Rates, but Actual Costs Varied by Task

Anthropic lists Opus 5 at $5 per million input tokens and $25 per million output tokens. Those rates are unchanged from Opus 4.8 and half Fable 5's rates of $10 for input and $50 for output.

Even with token rates 50% lower, the final bill may not fall by 50%. In Artificial Analysis's max-effort evaluation, the difference was smaller.

Artificial Analysis, July 25, 2026Opus 5Fable 5
Average cost per task$2.03$2.75
Total output tokens across the evaluation100 million87 million

Opus 5's token rates were half Fable 5's, but it cost 26% less per task in this evaluation. It used more output tokens to solve the same set of problems.

These results cannot be applied to every workload. Max effort is the setting that lets the model reason the longest, while the final cost depends on the type of task and the number of tokens the model uses.

The First External Evaluations Showed Only Small Gaps

Opus 5 finished ahead of Fable 5 in two evaluations published the day after launch. The gaps between the two models, however, were small.

Results Available on July 25, 2026Opus 5Fable 5Opus 4.8
AA Intelligence Index (max effort)6160—
SWE-bench Verified (vals.ai)97.00%95.00%88.60%

Artificial Analysis's Intelligence Index combines the results of several evaluations into one score. Opus 5 ranked first among 190 models and Fable 5 ranked third. Their positions were two places apart, but their scores differed by only one point.

Vals.ai's SWE-bench Verified asks models to fix issues from real open-source repositories. Opus 5 also finished ahead here, but a single evaluation cannot represent every kind of coding work.

Early Users Were Split

One Hacker News user shared a side-by-side comparison of the two models on 14 real work tasks. Ten ended in ties, Opus 5 performed better on three, and Fable 5 performed better on one. The user reported that Opus 5 cost about one-third as much as Fable 5.

This was not a public benchmark but one person's comparison based on their own work. The larger cost gap than in the Artificial Analysis evaluation may reflect differences in the tasks, effort settings, and sample size.

Another Hacker News thread included reports from people who chose Opus 5 for reasons other than performance. Some said Fable 5 refused tasks involving assembly-code debugging or login-screen work. Others cited data-retention periods and subscription usage limits. These are still only a handful of individual experiences, so it is not yet clear how often such issues occur.

Other users reached the opposite conclusion. Comments on a comparison post in r/ClaudeAI said Fable 5 stayed closer to the original intent and produced more usable results. Another commenter said they use Fable 5 for design and Opus 5 for implementation.

One Day Is Too Soon to Call

As of July 25, Opus 5 had not yet appeared on LMArena's text leaderboard, where Fable 5 held the top position. Epoch AI had created an Opus 5 page but had not posted a score. With Opus 5 results still missing from both sources, it was too early to settle the comparison based on the initial evaluations alone.

The size of Opus 5's cost advantage also varied between the external evaluation and the individual user's own work. Reports of people switching models because of safety filters remain limited to a few cases. More evidence is needed before saying which model is better for real work.

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