Quick Answer
Grok 4.5 vs Claude Opus 5 vs GPT-5.6 Sol (July 2026)
The Short Answer
Claude Opus 5 and GPT-5.6 Sol are the frontier picks; Grok 4.5 is the value pick. Opus 5 (launched July 24, 2026) leads SWE-bench Pro and Frontier-Bench; GPT-5.6 Sol leads SWE-bench Verified and the coding-agent index; Grok 4.5 ($2/$6 per MTok) trades a few benchmark points for roughly 3x lower cost per task.
Head-to-Head
| Grok 4.5 | Claude Opus 5 | GPT-5.6 Sol | |
|---|---|---|---|
| Maker | xAI | Anthropic | OpenAI |
| API in/out ($/MTok) | $2 / $6 | $5 / $25 | $5 / $30 |
| 30K/5K task cost | ~$0.09 | ~$0.28 | ~$0.30 |
| SWE-bench Pro | trails | 79.2% | 64.6% |
| SWE-bench Verified | trails | ~97% | ~96.2% |
| Coding Agent Index | mid | 78 | 80 (leads) |
| Context | ~1M (Grok 4.3 lineage) | 1M | large |
Where Each Wins
- Hardest coding + agentic + computer use → Claude Opus 5. It beats GPT-5.6 Sol on six benchmarks including agentic coding and computer use, and tops Frontier-Bench. Effort toggle (low→max) lets you trade cost for quality.
- Terminal coding + verified SWE-bench + raw agent index → GPT-5.6 Sol. Sol leads SWE-bench Verified (~96.2%) and the Artificial Analysis Coding Agent Index (80), and is strong on Terminal-Bench v2.
- Cost-per-task, high-volume agents → Grok 4.5. At $2/$6 it’s the cheapest of the three by a wide margin — about $0.09 on a typical task versus ~$0.28–0.30 for the frontier pair.
The Smart Play: Route, Don’t Pick
Most production teams don’t choose one. They default to the cheap model (Grok 4.5) for the 80% of requests that are easy, then escalate to Opus 5 or GPT-5.6 Sol on retries, complex refactors, or low-confidence outputs. That keeps the average cost near Grok’s while preserving frontier quality where it matters.
Sources
- Anthropic — Claude Opus 5 (July 24, 2026): anthropic.com/news/claude-opus-5
- Artificial Analysis — GPT-5.6 coverage: artificialanalysis.ai/articles/gpt-5-6-has-landed
- Vals AI — SWE-bench Verified leaderboard: vals.ai/benchmarks/swebench
- xAI — Grok models: x.ai