Tutorials, deep dives and product notes — built for developers.
OpenAI's cheapest tier cut its price 61%, cut its hallucination rate from 93% to 77%, and lost a point on the independent index. Same-harness data on both generations, where Luna regressed, where it improved, and the ten-week price collapse.
Across all six effort levels, GPT-6 Sol scores within a point of GPT-5.6 Sol and costs about half as much per task. Same-harness data on both, the full effort ladder, where coding improved, where knowledge work regressed, and the November price cliff.
OpenAI shipped GPT-6 Sol 90 minutes after Claude Opus 5.5, at half the token price. Artificial Analysis ran both on the same tests: Sol is cheaper to any index score up to about 44, then runs out of headroom. Every benchmark, both effort ladders and the real bill.
Opus 5.5 matches GPT-6 Astra on Terminal-Bench 4.0 for roughly 40% of the cost per task, with 5x cheaper cache reads. Astra keeps uncontested leads in science, maths and gated offensive security — and OpenAI says it is harder to monitor.
Opus 5.5 wins eight of the nine benchmarks Anthropic publishes against Fable 5.1 at 2.5x lower token price - but four of those margins sit inside the disclosed error bars. Includes the HAProxy same-task test, the 16-0 research-report result and the one-way thinking-block handoff.
DeepSeek V4.1 Flash wins 5 of the 15 benchmarks it shares with Claude Opus 5 — by an average of 1.94 points, while undercutting it by up to 41.7× on output price. Opus 5's 10 wins average 10.19 points. Full vendor data, community test reports, pricing math, charts and a routing verdict.
OpenAI's GPT-6 Astra vs Anthropic's Claude Fable 5.1: every benchmark, the independent indices, real-world head-to-heads, pricing deep dive, and who actually wins your workload.
Claude Opus 5 vs Kimi K3: Opus 5 leads the independent BenchLM aggregate 85.88 to 79.98 and posts a 43.3–43.5% Frontier-Bench score that K3 has never even been tested on.
Claude Opus 5 vs Claude Fable 5: Opus 5 beats Fable 5 on 7 of 12 benchmarks including Frontier-Bench (+9.6) and OSWorld 2.0 — at half the price ($25 vs $50/1M output). Fable 5 edges SWE-bench Pro by just 0.8 pts. Full comparison with radar charts, pricing, data retention, and verdict.
Claude Opus 5 vs GPT-5.6 Sol: Opus 5 leads 9 of 12 benchmarks including SWE-bench Pro (+14.6 pts) and ARC-AGI-3 (3.9× better). Sol counters with Terminal-Bench 2.1 (91.9% Ultra) and DeepSWE. Opus 5 costs 17% less on output ($25 vs $30/1M). Full comparison with radar charts, pricing, and verdict.
Kimi K3 vs GPT-5.6 Sol: Sol leads 6 of 9 shared benchmarks including DeepSWE and Terminal-Bench 2.1. K3 wins FrontierSWE, BrowseComp, and AA-Briefcase at 40% lower cost. Sol Ultra hits 91.9% on Terminal-Bench. Full comparison with radar charts and pricing.
Kimi K3 vs Claude Fable 5 across 35 benchmarks: Fable wins 22, K3 wins 12, 1 tie. K3 leads Terminal-Bench 2.1, SWE Marathon (+7), BrowseComp, and took #1 on the Frontend Code Arena — all at 70% less cost. Fable dominates FrontierSWE (+5.4), HLE (+9.8), and vision. Full scorecard with radar charts and pricing analysis.