The arena · AI model review
Claude Opus 4.8
by Anthropic
Anthropic's flagship Opus-tier model for long-horizon agentic coding; 1M context at $5/$25 per 1M tokens.
$25/1M out
Standard tier $5/$25 per 1M tokens (unchanged from Opus 4.7); fast mode research preview at $10/$50 (vs $30/$150 on Opus 4.7's deprecated fast tier); batch API 50% off at $2.50/$12.50; no long-context surcharge up to 1M tokens; prompt cache reads at $0.50/1M.
Anthropic
1M tokens (128K max output)
$5/1M in
$25/1M out
text, vision (image input up to 2576px, text output)
No
What is Claude Opus 4.8?
Anthropic's most capable Opus-tier model, released May 28, 2026. Tuned for long-horizon agentic coding, tool use, and honest self-assessment of its own work, with a 1M-token context window, 128K max output, and adaptive thinking with effort controls. Keeps the exact API surface and pricing of Opus 4.7.
Claude Opus 4.8 pros & cons
Pros
- SWE-Bench Pro 69.2% (vs 64.3% for Opus 4.7) and beats prior Opus models on CursorBench at every effort level; strong real-world reports on large refactors and multi-file bug hunts
- About 4x less likely than Opus 4.7 to let flaws in its own generated code pass unflagged; big jump on math reasoning (USAMO 2026: 96.7% vs 69.3%)
- 1M-token context and 128K output at unchanged $5/$25 pricing, with no long-context premium; batch API at 50% off ($2.50/$12.50)
- Fast mode (research preview) delivers up to 2.5x output speed at $10/$50, 3x cheaper than Opus 4.7's fast tier ($30/$150)
- Unique API features for agents: mid-conversation system messages that preserve the prompt cache, and Dynamic Workflows spawning parallel subagents in Claude Code
- 84% on Online-Mind2Web browser automation and record score on Legal Agent Benchmark (first model past 10% all-pass); strong enterprise knowledge work (Box reports 87% vs 77% internally)
Cons
- Turn-by-turn regressions reported: missed obvious instructions in planning docs, answering a narrow slice of the goal, and worse one-shot simple UI generation than 4.7
- Writing style criticized by heavy users: excessive hedging, over-cautious editing that 'cuts anything bold or funny' (Steve Yegge), and pushback loops even against well-evidenced theses
- Language-mixing quirk: users report random Chinese, Cyrillic, or Greek insertions in long research threads
- Visible quality degradation past ~200K tokens in hands-on use despite the advertised 1M window
- Vending-Bench regression: fell for scam suppliers about 30x more than 4.7 and negotiates worse (a side effect of stricter honesty alignment)
The arena’s verdict
A drop-in upgrade for Opus 4.7 users: identical API surface and $5/$25 pricing with real gains on long-horizon agentic coding, code review, and enterprise analysis. Choose it if you run Claude Code, multi-file migrations, security audits, or agent pipelines that inspect, act, and verify over many steps. Skip it for quick one-shot UI snippets or prompts tightly tuned to 4.7 behavior, where users report regressions, and pick Sonnet 5 ($3/$15, intro $2/$10 through Aug 2026) if cost matters more than ceiling capability. Writers sensitive to hedging and over-cautious editing may find its style frustrating.
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Would you recommend Claude Opus 4.8, or warn the crowd away?
Top Claude Opus 4.8 alternatives
All alternativesAnthropic's fastest model: about 90% of Sonnet 4.5's coding skill at $1/$5 per 1M tokens, 200K context.
Anthropic's April 2026 Opus: 87.6% SWE-bench Verified, 1M context, high-res vision, now behind Opus 4.8
Anthropic's most agentic Sonnet: near Opus 4.8 quality on coding and agents at $3/$15 with 1M context
Compare Claude Opus 4.8 head-to-head
What the crowd says
“Writing took a hit. It hedges everything and edits any bold or funny line out of my drafts. Also caught it answering a narrow slice of my planning doc and calling it done.”
“Threw USAMO-level math at it for a lark and it just grinds through. 96.7 vs 69 for 4.7 tracks with what I see. Same $5/$25, 1M context, no excuse not to switch.”
“Upgraded from 4.7 for a monorepo refactor and the difference is real. It actually flags its own sketchy code instead of shipping it. Multi-file bug hunts feel way less babysat.”
Claude Opus 4.8: frequently asked questions
How much does Claude Opus 4.8 cost per 1M tokens?
Claude Opus 4.8 costs $5/1M in per 1M input tokens and $25/1M out per 1M output tokens. Standard tier $5/$25 per 1M tokens (unchanged from Opus 4.7); fast mode research preview at $10/$50 (vs $30/$150 on Opus 4.7's deprecated fast tier); batch API 50% off at $2.50/$12.50; no long-context surcharge up to 1M tokens; prompt cache reads at $0.50/1M.