The arena · AI model review
Claude Opus 4.6
by Anthropic
Anthropic's Feb 2026 Opus: 1M context, adaptive thinking, 80.8% SWE-bench, now superseded by Opus 4.8.
$25/1M out
Standard tier $5/$25 per 1M tokens; full 1M context now at standard rates (the launch-time premium of $10/$37.50 above 200K tokens was later dropped), batch API 50% off ($2.50/$12.50), US-only inference (inference_geo) 1.1x multiplier.
Anthropic
1M tokens (128K max output)
$5/1M in
$25/1M out
text, vision (image input), text output
No
What is Claude Opus 4.6?
Frontier Opus-class model released February 5, 2026. First Opus with a 1M-token context window, adaptive thinking, and an effort parameter (low to max). Posted 80.8% on SWE-bench Verified and the top Terminal-Bench 2.0 score at launch; later superseded by Opus 4.7 and 4.8 at identical pricing.
Claude Opus 4.6 pros & cons
Pros
- 80.8% SWE-bench Verified (25-trial average) and top Terminal-Bench 2.0 score at launch, the leading agentic coding model of its generation (Feb 2026)
- First Opus with a 1M-token context window: 76% on MRCR v2 8-needle at 1M tokens vs 18.5% for Sonnet 4.5
- Large reasoning jump over Opus 4.5: ARC-AGI-2 68.8% vs 37.6%, +190 Elo on GDPval-AA economic-value tasks (~144 Elo over GPT-5.2)
- Kept Opus 4.5 pricing ($5/$25 per 1M tokens) despite the gains; full 1M context now billed at standard rates, 50% batch discount
- Adaptive thinking plus effort parameter (low/medium/high/max) to trade intelligence, latency and cost per request
- Strong autonomous agent behavior: parallelizes work and needs less handholding than Opus 4.5 (Every.to Vibe Check)
Cons
- Slower and more verbose than Opus 4.5; reviewers report the pace 'wavers under load' on long agentic runs (Every.to)
- Writing regressed: in blind tests Every.to's team preferred Opus 4.5's prose, and 4.6 shows more AI-isms like 'X not Y' constructions
- Sometimes makes unexpected changes and 'doesn't always know its own skills', requiring closer supervision than GPT-5.x Codex per reviewers
- Superseded within months by Opus 4.7 and 4.8 at the same $5/$25 price, and fast mode is not available on 4.6 since June 2026 (requests run at standard speed)
- Some devs report benchmark fatigue: day-to-day coding gains over 4.5 are harder to feel than the scores suggest, and SWE-bench itself was flat vs 4.5 (80.8% vs 80.9%)
The arena’s verdict
A clear upgrade over Opus 4.5 for agentic coding and long-context work at identical pricing, and it held the top agentic coding benchmarks at launch. In mid-2026 however there is little reason to start new projects on it: Opus 4.8 costs the same $5/$25 and outperforms it across the board, so pick 4.6 mainly to pin an already-validated behavior. Writers should avoid it, since blind tests preferred Opus 4.5's prose, and latency-sensitive users should note it is slower than 4.5 with no fast mode option.
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Top Claude Opus 4.6 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 flagship Opus-tier model for long-horizon agentic coding; 1M context at $5/$25 per 1M tokens.
Compare Claude Opus 4.6 head-to-head
Claude Opus 4.6: frequently asked questions
How much does Claude Opus 4.6 cost per 1M tokens?
Claude Opus 4.6 costs $5/1M in per 1M input tokens and $25/1M out per 1M output tokens. Standard tier $5/$25 per 1M tokens; full 1M context now at standard rates (the launch-time premium of $10/$37.50 above 200K tokens was later dropped), batch API 50% off ($2.50/$12.50), US-only inference (inference_geo) 1.1x multiplier.