Claude Fable 5.1 wins on coding (100 vs 94) and writing quality. GPT-5.6 Terra wins on price ($2 vs $10/1M input). For most workflows, Claude Fable 5.1 is the stronger default — new frontier leader — better than fable 5 on every published benchmark, and cheaper to run.
The shortest way to see the safest default, the lower-cost option, and the specialist pick before you read deeper.
Claude Fable 5.1 is the safest overall answer here when you want the strongest default instead of the lowest list price.
Grok 4.5 is the lower-cost option to start with when you still need useful output at scale.
GPT-5.6 Terra is the better pick when response speed matters more than maximum reasoning depth.
Claude Fable 5.1 leads on coding with a score of 100 vs 94 for GPT-5.6 Terra.
GPT-5.6 Terra has the larger context window: 1.05M vs 1M for Claude Fable 5.1.
GPT-5.6 Terra is cheaper at $2/1M input tokens vs $10/1M for Claude Fable 5.1.
Go with Claude Fable 5.1 if you want one model to handle coding and research — it targets frontier agentic coding, long-horizon autonomous work, and agentic scientific research.
GPT-5.6 Terra earns its place when your work is mostly high-volume production and enterprise workloads, even though it loses the overall count here.
GPT-5.6 Terra is the more cost-efficient option at $2/1M input — Claude Fable 5.1 costs 5x more per input token, so the gap is worth taking seriously wherever token volume rather than peak quality drives the bill.
Switch the scoring lens to see whether the top answer changes when you care more about cost, speed, or long-document work.
Anthropic / Premium / Sep 1, 2026
New frontier leader — better than Fable 5 on every published benchmark, and cheaper to run.
Ranks models by the broadest mix of coding, writing, research, and long-context usefulness.
You need low latency, or your workload is uncached and cost-sensitive — Claude Opus 5 is half the base price and within a few points on agentic coding.
The fastest way to see where the recommendation shifts when your priority changes.
New frontier leader — better than Fable 5 on every published benchmark, and cheaper to run.
Best OpenAI value — near-flagship capability at 60% off.
Every figure below is the provider's list price or a published capability score — the same numbers the recommendation on this page is built from.
| Model | Input | Output | Est. month | Context | Speed | Coding | Writing | Research |
|---|---|---|---|---|---|---|---|---|
| Claude Fable 5.1Anthropic | $10.00/1M | $50.00/1M | $200 | 1M tokens | Deliberate | 100 | 98 | 100 |
| GPT-5.6 TerraOpenAI | $2.00/1M | $12.00/1M | $44 | 1.1M tokens | Balanced | 94 | 92 | 93 |
Capability scores are out of 100 and reflect our own weighting of published benchmarks and production signals — see how we evaluate models. “Est. month” assumes 10M input and 2M output tokens at list price, with no batch or caching discounts applied, so treat it as a ceiling.
What each one is genuinely good at, where it falls down, and the situations we would steer you away from it — not just the headline score.
Anthropic's September 1, 2026 frontier release and the new capability ceiling for coding, agents, and scientific work. Base pricing is unchanged at $10/$50, but cache reads dropped 75% to $0.25/1M — roughly 25% cheaper on typical workloads and up to 45% cheaper on agentic ones. 1M context, 128K output, adaptive thinking always on.
You need low latency, or your workload is uncached and cost-sensitive — Claude Opus 5 is half the base price and within a few points on agentic coding.
The new frontier leader, and the rare upgrade that costs less than the model it replaces. Base $10/$50 pricing did not move, but a 75% cut to cache reads makes typical workloads ~25% cheaper than Fable 5 and heavily agentic ones ~45% cheaper — while more than doubling Fable 5 on agentic science and beating Opus 5 on agentic coding. If you were already on Fable 5, switching is a straight win. If you were on Opus 5 for the price, it still costs 2x on uncached tokens.
Released September 1, 2026 alongside Claude Mythos 5.1, the first update to the Mythos-class line since Fable 5 on June 9. API ID claude-fable-5-1; generally available on the Claude API, Amazon Bedrock, Google Cloud, and Microsoft Foundry. Published launch numbers (Fable 5.1 / Fable 5 / Opus 5 / GPT-5.6 Sol): Terminal-Bench-Science 0.1 52.6 / 24.7 / 29.0 / 22.4; Terminal-Bench 4.0 55.8 / 42.0 / 52.3 / 37.3; CursorBench 3.2.0 73.4 / 70.5 / 70.0 / 67.2; AutomationBench 31.4 / 17.1 / 26.9 / 19.6; OSWorld 2.0 strict 41.7 / 36.1 / 39.6; Humanity's Last Exam (no tools) 60.9 / 57.8 / 56.6; GDPval-AA v2 1853 / 1723 / 1824 / 1711. GDPval-AA v2 is rescaled from the v1 numbers quoted on the Fable 5 page and is not directly comparable to them.
The balanced mid-tier of the GPT-5.6 family — GPT-5.5-class capability at a fraction of the price, built for production workloads at scale.
You need Sol-level computer use or Opus 5-level repo engineering.
The sensible OpenAI default for production. Terra delivers ~97% of Sol's benchmark line at 40% of the output price, making GPT-5.5's rate card look obsolete. Pick Sol only for computer-use agents and the hardest reasoning.
Launched at $2.50/$15, cut to $2/$12 on July 30, 2026. Long-context above 272K: $4/$18. Part of the government-reviewed GPT-5.6 family, fully public July 9, 2026.
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Claude Fable 5.1 wins on more of the categories we score — coding, research, long context — so it is the better default of the two. GPT-5.6 Terra is the better pick when your work is mostly high-volume production and enterprise workloads. Neither is universally "better": Claude Fable 5.1 is aimed at frontier agentic coding and long-horizon autonomous work, GPT-5.6 Terra at high-volume production and enterprise workloads.
GPT-5.6 Terra is cheaper at $2/1M input and $12/1M output. Claude Fable 5.1 costs $10/1M input and $50/1M output.
GPT-5.6 Terra has the larger context window at 1.05M tokens vs Claude Fable 5.1's 1M. For large document analysis, GPT-5.6 Terra is the stronger pick.
Claude Fable 5.1 is better for coding with a score of 100 vs GPT-5.6 Terra's 94 (out of 100). Claude Fable 5.1 is the overall coding leader in this directory at 100/100.
GPT-5.6 Terra is faster with a balanced speed rating (score: 3) vs Claude Fable 5.1's deliberate rating (score: 2). Speed matters most for interactive and high-throughput work; for batch jobs the Claude Fable 5.1 latency penalty is usually invisible.
Base rates are still $10/$50 per 1M — double Claude Opus 5 for anything that is not cache-heavy. Anthropic published no SWE-bench Verified or SWE-bench Pro figure for 5.1 at launch. On Claude Pro it only runs on pay-as-you-go credits; Max includes it up to 50% of weekly limits. Avoid it if you need low latency, or your workload is uncached and cost-sensitive — Claude Opus 5 is half the base price and within a few points on agentic coding. That is the main case for looking at GPT-5.6 Terra instead.
Big gap to Sol on computer use (OSWorld 50.2% vs 62.6%) — not a drop-in Sol replacement for agents. Well behind Claude Opus 5 on repository-level coding (SWE-bench Pro ~63% vs 79.2%). Avoid it if you need Sol-level computer use or Opus 5-level repo engineering. Against Claude Fable 5.1 specifically, the gap shows up most on coding (100 vs 94).
Take a moderate workload of 10M input and 2M output tokens a month. Claude Fable 5.1 runs $200.00 (at $10/1M in and $50/1M out); GPT-5.6 Terra runs $44.00 (at $2/1M in and $12/1M out). That is a $156.00/month difference — GPT-5.6 Terra is the cheaper of the two at this volume, and the gap scales linearly as you send more. Output tokens dominate the bill on both, so prompt length matters far less than response length.
Yes, and for most teams that beats picking one. A common split is Claude Fable 5.1 for frontier agentic coding and long-horizon autonomous work, with GPT-5.6 Terra handling high-volume production and enterprise workloads. Routing high-volume, low-stakes calls to GPT-5.6 Terra at $2/1M and reserving Claude Fable 5.1 for the hard cases is usually the cheapest arrangement that does not cost you quality.