Tutorials, deep dives and product notes — built for developers.
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.
Anthropic's Claude Opus 5.5 matches Fable 5.1 on most work at $4/$20 per million tokens: 66.4% on Terminal-Bench 4.0, 1,846 GDPval-AA Elo, and 40% lower cost per task than Opus 5. Full benchmark table with footnotes, real tester results, the four breaking API changes, and where GPT-6 Astra still wins.
Interactive Terminal-Bench 4.0 Leaderboard: GPT-6 Astra leads at 58.2% and Claude Fable 5.1 at 57.9%, with GLM-5.3 top open-weight at 41.8%. Complete scores, run costs, token counts, and verification links across 66 hard terminal tasks.
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.
GPT-6 Astra review: every benchmark, what people built, pricing, and the Critical cybersecurity rollout — with sources.
A data-backed comparison of Grok 4.6 and Claude Fable 5 across benchmarks, pricing, speed, latency, and context window — with charts and a clear verdict on which to choose.
Interactive FrontierBench v0.1 leaderboard with Claude Opus 5 leading at 42.7%, GLM-5.3 at 28.3%, Gemini 3.7 Flash at 14.9%, and 12 models ranked by professional computer-work task completion. Renamed Terminal-Bench 3.0. Updated August 21, 2026.
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.
Interactive FrontierCode v1.1 Main leaderboard with Claude Fable 5 at 53.5%, Claude Opus 5 at 53.4%, Grok 4.6 at 48.0%, and 34 models ranked by production-code pull request quality. Updated August 14, 2026.
Interactive DeepSWE v1.1 leaderboard updated with Muse Spark 1.3 at 75.4%, GPT-6 Astra at 74.1%, and Claude Fable 5.1 at 67.4%. 28+ models ranked by long-horizon software engineering ability. Updated September 2026.
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.
GPT-5.6 Sol vs Claude Fable 5: Sol leads on agentic coding and price; Fable leads SWE-bench Pro and aggregate intelligence. Rich charts, radar, cost math, and sourced guidance.