Claude Opus 5 vs Llama 4 (405B)
Head-to-head technical comparison of intelligence, capabilities, and API pricing.
Which should you use?
Claude Opus 5 leads on the composite index by 6.1 points (96.6 vs 90.5).
Only Llama 4 (405B) ships open weights, which decides it outright if the workload has to run on your own hardware.
Pick Claude Opus 5 when
- Higher composite index — 96.6 against 90.5, a gap of 6.1 points.
- Ahead on Arena Elo by 53 points (1493 vs 1440), which is outside the board's published confidence intervals.
- Stronger on MMLU-Pro: 95.7% against 90.5%.
Pick Llama 4 (405B) when
- Open weights, so it is the only one of the two you can run on your own hardware or keep data entirely in-house.
Where these numbers come from
Figures as of 2026-09-07. Arena Elo and pricing are read from the public board and each vendor's own pricing page; see the full leaderboard for all 34 models and which columns are measured rather than estimated, or the benchmark matrix for scores benchmark by benchmark.
Our reporting on Anthropic and Meta
Autonomy Is Now the Default: Why the AI Safety Ratchet Won't Reverse
Three August 2026 releases made autonomous AI action the default mode. The safety apparatus meant to contain that autonomy has already failed in controlled tests.
Meta Pays ~95% Discount for Muse Spark Users Who Share Agent Data
Meta's Muse Spark slashes API prices by up to 95% for users who share prompts and outputs — putting an explicit dollar figure on agentic trace data.
Anthropic's Apache 2.0 Commerce Agents Blueprint: Skills Over Subagents
Anthropic's open-source commerce-agents repo ships shopping and merchant agents, four verticals, and a gate layer—all under Apache 2.0.