QUICK VERDICT — UPDATED JULY 26, 2026
● Cheaper: Grok 4.5 — $2/$6/M vs Opus 5 $5/$25/M (60% cheaper input, 76% cheaper output)
● Better ARC-AGI-3: Claude Opus 5 — 30.2% (Grok 4.5 not published)
● Better Terminal-Bench: Grok 4.5 — 83.3% (Opus 5 not published on this benchmark)
● Better writing quality: Claude Opus 5 — Anthropic's consistent advantage
● Live data: Grok 4.5 only — X data access in every session
● Effort control: Claude Opus 5 only — 5-level toggle
● Privacy concern: Grok Build SSH key upload (patched) — Claude Code has none known
| Feature | Claude Opus 5 | Grok 4.5 |
|---|
| Input /1M | $5 | $2 |
| Output /1M | $25 | $6 |
| ARC-AGI-3 | 30.2% | Not published |
| Terminal-Bench 2.1 | Not published | 83.3% |
| Effort control | 5-level toggle | None |
| Live data | No | X data always |
Claude Opus 5 for: Writing quality, complex reasoning (ARC-AGI-3 30.2%), fine-grained cost control via effort toggle, production workloads requiring auto-fallback instead of hard refusals, and regulated industries where Grok Build's privacy incident history matters.
Grok 4.5 for: Cost-sensitive high-volume workloads (60-76% cheaper), agentic terminal coding (Terminal-Bench 83.3%), live X data research, SuperGrok subscribers who want voice + coding + live data in one plan.
Last updated July 26, 2026. Related: Claude Opus 5 review → · Grok 4.5 review →