Anthropic · Closed-API Model · Current flagship
Claude Opus 4.8: Anthropic's Flagship, Tested
Claude Opus 4.8 (May 28, 2026) is Anthropic's current flagship and, as of June 2026, the #1 model on the Artificial Analysis Intelligence Index at 61.4 — narrowly ahead of GPT-5.5 (60.2) and its own predecessor Opus 4.7 (57.3). It scores 88.6% on SWE-Bench Verified and 69.2% on SWE-Bench Pro, keeps Opus 4.7's $5/$25 per-million-token pricing and 1M-token context, and adds an optional 2.5× Fast Mode plus an effort control. This review covers what changed from 4.7, how Fast Mode and effort work, the benchmark numbers, and which open-weight models come closest if you need to self-host.
Current flagship (June 2026): Opus 4.8 is Anthropic's top model. It replaced Claude Opus 4.7 (April 16, 2026), which is now the previous generation. Above the Opus tier, Anthropic's Mythos-class Fable 5 & Mythos 5 remains suspended worldwide by export-control order. Source: Anthropic's 4.8 announcement.
Note: Opus 4.8 is API-only — it cannot be downloaded or run locally. For frontier-class reasoning you can self-host, see DeepSeek V4-Pro, Kimi K2.6, and GLM-5.
Key takeaways
- →#1 Intelligence Index — 61.4 on Artificial Analysis, ahead of GPT-5.5 (60.2) and Opus 4.7 (57.3).
- →88.6% SWE-Bench Verified · 69.2% SWE-Bench Pro — leads agentic coding (GPT-5.5 is 58.6% on Pro).
- →$5/$25 per Mtok — flat vs Opus 4.7; optional Fast Mode is $10/$50 for ~2.5× speed.
- →1M context + effort control — effort defaults to high; extra/max for the hardest tasks.
- →API-only — for self-hosting, DeepSeek V4-Pro and Kimi K2.6 are the closest open-weight matches.
Quick verdict
Opus 4.8 is the model to default to if you want the single strongest closed model in June 2026 — it tops the Artificial Analysis Intelligence Index and leads agentic coding (69.2% SWE-Bench Pro). It's a drop-in upgrade over Opus 4.7 at the same $5/$25 price and 1M context, so there's little reason to stay on 4.7.
Where it loses: for most everyday coding, Claude Sonnet 4.6 ($3/$15) still wins on value — Opus 4.8 is worth its premium only on the hardest 5-10% of tasks. And it's API-only: for privacy-required or offline work, DeepSeek V4-Pro is the closest frontier open-weight you can self-host.
Opus 4.8 specs at a glance
| Vendor | Anthropic |
| Release date | May 28, 2026 |
| Status | Current flagship |
| Model ID | claude-opus-4-8 · 1M variant claude-opus-4-8[1m] |
| Context window | 1,000,000 tokens (default on API, Bedrock, Vertex; 200K on Microsoft Foundry) |
| Modalities | Text · Code · Vision |
| Effort control | Yes — defaults to high (extra/max available) |
| Fast Mode | Optional — ~2.5× speed at $10/$50 per Mtok |
| License | Proprietary |
| Local self-hostable? | No |
What changed from Opus 4.7?
Opus 4.8 landed 41 days after Opus 4.7 — a drop-in upgrade at the same list price and context. The gains show up across both real-world agentic coding and frontier reasoning, plus the new Fast Mode.
| Opus 4.8 (current) | Opus 4.7 (previous) | |
|---|---|---|
| Released | May 28, 2026 | April 16, 2026 |
| SWE-Bench Verified | 88.6% | 87.6% |
| SWE-Bench Pro | 69.2% | 64.3% |
| Artificial Analysis Index | 61.4 | 57.3 |
| Context window | 1M tokens | 1M tokens |
| API pricing (in/out) | $5 / $25 per Mtok | $5 / $25 per Mtok |
| Fast Mode | ~2.5× at $10/$50 | — (pricier) |
Beyond the scores, Anthropic highlights parallel-subagent dynamic workflows in Claude Code, mid-task system messages on the Messages API, and measurable honesty gains in its alignment assessment. The effort parameter and the rest of the platform features carry over from 4.7 unchanged. Sources: Anthropic news · Claude API docs.
Fast Mode & effort control
Opus 4.8 gives you two levers to trade speed, cost, and quality, and you can combine them per request.
Fast Mode — ~2.5× speed, $10/$50 per Mtok
An optional setting that runs Opus 4.8 at roughly 2.5× the standard output throughput for double the per-token price ($10/$50 vs $5/$25). Anthropic ships it about 3× cheaper than the equivalent fast mode on previous Claude models. Reach for it on latency-sensitive agents, interactive coding loops, and high-throughput pipelines where wall-clock time matters more than the lowest per-token cost.
Effort control — defaults to high
The effort parameter tunes how hard the model works on a response — an output-level control, not a raw thinking-token budget. It defaults to high across the Claude API and Claude Code, with higher settings (extra/max) for the hardest tasks; on higher effort Claude thinks more frequently and more deeply. Artificial Analysis measured Opus 4.8 at its max effort setting to report the peak 61.4 Intelligence Index score.
Benchmarks vs the competition
| Benchmark | Opus 4.8 | Opus 4.7 | GPT-5.5 | Gemini 3.1 Pro |
|---|---|---|---|---|
| Artificial Analysis Index | 61.4 | 57.3 | 60.2 | — |
| SWE-Bench Verified | 88.6% | 87.6% | 85.1% | 87.9% |
| SWE-Bench Pro (agentic) | 69.2% | 64.3% | 58.6% | — |
| GPQA Diamond (PhD science) | 88.4% | 87.3% | 86.0% | 88.2% |
| AIME 2025 (math) | 93.6% | 92.8% | 95.2% | 94.0% |
Sources: Anthropic Opus 4.8 announcement and Claude API docs, Artificial Analysis Intelligence Index v4.0 (Opus 4.8 measured at max effort). Cross-model figures use each vendor's reported numbers; harnesses differ, so treat small gaps as ties. SWE-Bench Pro is Anthropic-reported (vendor evaluation). · Artificial Analysis
Pricing & access
API
- Standard: $5 / $25 per 1M tokens
- Fast Mode: $10 / $50 per 1M tokens (~2.5× speed)
- Cached input: 90% off
- Batch: 50% off (24h SLA)
Subscription
- Claude Pro: $20/mo — limited Opus 4.8
- Claude Max: $100-200/mo — much higher Opus quota
- Bedrock / Vertex: same per-token pricing
Opus 4.8 is the priciest closed model in everyday use, but it's flat to Opus 4.7 and undercuts GPT-5.5 ($5/$30) and GPT-5.5 Pro ($30/$180). For privacy or predictable costs, a self-hosted DeepSeek V4 rig trades a one-time hardware spend for unlimited inference.
When to pick Opus 4.8
- ✓You want the single strongest closed model in June 2026 (#1 Intelligence Index, leads agentic coding).
- ✓Hard, multi-step agentic work in Claude Code where the 69.2% SWE-Bench Pro edge pays off.
- ✓Latency-sensitive pipelines that benefit from the optional ~2.5× Fast Mode.
- ✓Anthropic-stack teams — Opus 4.8 is a drop-in upgrade from Opus 4.7 at the same price.
When to pick something else
- →Best-value everyday coding → Claude Sonnet 4.6 ($3/$15, 1M context).
- →Competition math + ChatGPT ecosystem → GPT-5.5.
- →Privacy-required or offline → DeepSeek V4-Pro or Kimi K2.6.
- →Lowest frontier pricing → Grok 4.3 at $1.25/$2.50.
FAQ
What is Claude Opus 4.8?
Opus 4.8 vs Opus 4.7: what changed?
How much does Claude Opus 4.8 cost?
What is Opus 4.8 Fast Mode?
What is the effort control?
Opus 4.8 vs GPT-5.5: which is better?
Can I run Claude Opus 4.8 locally?
Related models
- → Claude Opus 4.7 — the predecessor; same price, lower benchmarks
- → Claude Sonnet 4.6 — your default for ~90% of coding work at $3/$15
- → Claude Fable 5 & Mythos 5 — Anthropic's Mythos tier above Opus, suspended worldwide by export order
- → GPT-5.5 — closest closed alternative; #2 on the Intelligence Index
- → Gemini 3.1 Pro — 1M context + explicit thinking tiers
- → Grok 4.3 — xAI's frontier model at far lower $1.25/$2.50 pricing
- → DeepSeek V4-Pro — open-weight frontier alternative you can self-host
- → Best AI models 2026 — pillar comparison
Go from reading about AI to building with AI
20 structured courses. Hands-on projects. Runs on your machine. Start free.
Written by the Local AI Master Team
The team behind Local AI Master
We build Local AI Master around practical, testable local AI workflows: model selection, hardware planning, RAG systems, agents, and MLOps. The goal is to turn scattered tutorials into a structured learning path you can follow on your own hardware.