Anthropic shipped Claude Opus 5 today, July 24, 2026. The one-line pitch is unusually blunt for a launch post: a thoughtful, proactive model that "comes close to the frontier intelligence of Claude Fable 5 at half the price." The model ID is claude-opus-5, it's live everywhere Claude runs, and it's now the default on Claude Max and the strongest model on Claude Pro.
If you've been reaching for Fable 5 for the hard problems and eating the cost, this is the release aimed squarely at you. Here's what actually changed — and where the marketing outruns the fine print.
The pitch, decoded
Opus 5 slots in above Opus 4.8 and just under Fable 5 — but at Opus pricing, not Fable pricing. Anthropic's whole framing is a price/intelligence argument: you give up a razor-thin slice of frontier capability and pay half as much for the tokens.
| Opus 4.8 | Opus 5 | Fable 5 | |
|---|---|---|---|
| Input / Mtok | $5 | $5 | $10 |
| Output / Mtok | $25 | $25 | $50 |
| Positioning | prior default | new Max default | frontier |
Same sticker price as Opus 4.8, roughly double the delivered capability on the headline benchmarks. That's the trade.
Fast Mode is available on Opus 5 too: 2× the base token price for output roughly 2.5× faster. It's the same Opus 5 weights — not a smaller model — just served on faster infrastructure.
Benchmarks: where it lands
Anthropic's own comparison table pits Opus 5 against Fable 5, Opus 4.8, and GPT-5.6 Sol. Opus 5 tops most rows — but not all, and the exceptions are worth seeing too (bold = row leader):
| Benchmark | Opus 5 | Fable 5 | Opus 4.8 | GPT-5.6 Sol |
|---|---|---|---|---|
| Agentic terminal coding — Frontier-Bench v0.1 | 43.3% | 33.7% | 21.1% | 34.4% |
| Knowledge work — GDPval-AA v2 | 1861 | 1747 | 1593 | 1736 |
| Novel problem-solving — ARC-AGI-3 | 30.2% | — | 1.5% | 7.8% |
| Agentic search — BrowseComp | 90.8% | 87.4% | 84.3% | 90.4% |
| Multidisciplinary reasoning — Humanity's Last Exam (no tools) | 56.3% | 56.5% | 49.8% | — |
| Multidisciplinary reasoning — Humanity's Last Exam (with tools) | 64.7% | 63.9% | 57.9% | — |
| Computer use — OSWorld 2.0 | 70.6% | 66.1% | 55.7% | 62.6% |
| Agentic coding — DeepSWE v1.1 | 68.8% | 69.7% | 59.0% | 72.7% |
| Agentic coding — FrontierCode v1.1 (Main) | 53.4% | 53.5% | 46.5% | 47.5% |
| Business workflows — AutomationBench | 26.0% | 17.4% | 17.0% | 18.1% |
| Legal — Legal Agent Benchmark (held-out) | 11.7% | 13.3% | 10.4% | 2.5% |
| Health — HealthBench Professional | 59.8% | 66.0%* | 57.4% | 60.5% |
*Health's leader is Mythos 5 at 66.0% — Anthropic shows it in the Fable 5 column in place of a published Fable figure. GDPval-AA v2 is an Elo-style score, not a percentage.
Read it and the "near-Fable at half the price" pitch holds up: Opus 5 wins agentic coding, computer use, automation, and novel problem-solving outright, trades blows with Fable 5 on reasoning, and cedes only a few rows — DeepSWE to GPT-5.6 Sol, and a couple of narrow ones (no-tools reasoning, legal, health) to Fable 5 / Mythos 5.
A few things the table leaves out:
- Cost, not just score. On CursorBench 3.2 Opus 5 lands within 0.5% of Fable 5's peak at half the cost per task, and the OSWorld win above comes at ~one-third of Fable 5's cost. The release is as much a price/performance argument as a raw-capability one.
- Science. On Anthropic's internal life-sciences evals, Opus 5 is +10.2 points over Opus 4.8 on organic chemistry and +7.7 points on protein-sequence tasks.
- Finance. Financial-modeling accuracy is up ~9 points on average — and it gets there in one-third fewer turns.
The fewer-turns detail matters more than it looks: on agentic work, turns are latency and tokens. A model that reaches the right answer in fewer steps is cheaper twice over.
The qualitative jump: verification, not just generation
The benchmark story is "near-Fable at half price." The behavioral story is about self-correction. Anthropic describes Opus 5 as noticeably better at:
- Catching its own logical faults during planning — flagging a flawed approach before it writes the code, rather than after the tests fail.
- Debugging and root-cause analysis — chasing a failure to its source instead of patching symptoms.
- Building its own scaffolding — writing test harnesses and validation systems autonomously to check its work.
- Longer-horizon consistency — holding a multi-step task together across many steps without drifting off the goal.
This is the difference reviewers keep pointing at. JetBrains' AI lead called it "the clearest jump in problem-solving we've seen from one Claude model to the next"; Cursor's co-founder put it as "near Fable 5 intelligence at Opus speed and cost"; Devin's CEO said it "approaches Fable-level performance at half the cost." The through-line: it's not that Opus 5 knows more, it's that it checks itself more.
Visual and creative output improved too — cleaner animations, better small games and 3D, and stronger artifacts for presentations — but the center of gravity of this release is agentic reliability.
Safety: quieter overall, deliberately weaker at one thing
Two things are worth separating here, because Anthropic is doing something unusual.
General alignment went up. Opus 5 posts the lowest misaligned-behavior score (2.3) of any recent Claude model and the lowest rates of deceptive behavior, with better adherence to the Constitutional-AI principles.
Offensive-cyber capability was deliberately held back. Opus 5 sits behind Mythos 5 on both biology research and offensive cybersecurity — by design. It can identify vulnerabilities about as well as Mythos 5, but it's substantially weaker at exploit development (shown on an OSS-Fuzz evaluation), and Anthropic says it simply wasn't trained on cyber tasks.
The practical upshot for developers is a much lighter touch than Fable 5's lockdown:
- Cybersecurity classifiers are ~85% less restrictive than Fable 5's.
- Source-code vulnerability scanning is allowed; binary-based scanning and exploit generation are blocked.
- Requests that trip a safety classifier get an automatic fallback to Opus 4.8 on Claude.ai, Claude Code, and Claude Cowork — you get an answer from the safer model instead of a hard refusal.
- Enterprises and vetted researchers can apply to a Cyber Verification Program for access to a less-restricted version.
If you remember the Fable 5 / Mythos 5 saga — the export-control suspension, the gated glasswing preview — this is Anthropic threading the same needle differently: ship the capability broadly, cap the one dimension that caused the trouble.
New platform features
Two beta features ride along with the launch:
- Mid-conversation tool changes on the Claude Platform — swap the available tools partway through a session without starting over. Useful for long agent runs where the toolset should change as the task moves phases.
- Automatic fallbacks on the API for safety-flagged requests — the same Opus-4.8 fallback behavior, now available programmatically instead of only in the first-party apps.
Should you switch?
- On Max: you're already on it — Opus 5 is the new default.
- On Pro: it's the strongest model you can select; make it your default for anything non-trivial.
- On the API: if you were paying Fable 5 rates for coding or agent work, run your own eval, but the CursorBench and OSWorld cost-adjusted numbers make Opus 5 the obvious first thing to try — same
$5 / $25as Opus 4.8, near-Fable output.
The honest summary: this isn't a new intelligence ceiling — Fable 5 still holds that, and Mythos 5 still leads on the capabilities Anthropic gates. It's a value release, and on the coding/agentic axis most developers actually live on, the value is hard to argue with.