Claude Fable 5.1 wins on coding (100 vs 86) and writing quality and context window (1M vs 500K). Grok 4.6 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.
Mistral: Mistral Nemo is the lower-cost option to start with when you still need useful output at scale.
Grok 4.6 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 86 for Grok 4.6.
Claude Fable 5.1 has the larger context window: 1M vs 500K for Grok 4.6.
Grok 4.6 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.
Grok 4.6 earns its place when your work is mostly long-running agents and multi-step codebase work, even though it loses the overall count here.
Grok 4.6 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 2, 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.
Finishes agent tasks in half the turns — cheap where it counts.
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 | $5.00/1M | $25.00/1M | $100 | 1M tokens | Deliberate | 100 | 98 | 100 |
| Grok 4.6xAI | $2.00/1M | $6.00/1M | $32 | 500k tokens | Fast | 86 | 84 | 88 |
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.
xAI's long-horizon agent model — it finishes agentic tasks in roughly half the turns of its rivals, which makes it cheaper in practice than its per-token price suggests.
You need a published SWE-bench score to justify the pick, or your prompts routinely cross 200K tokens where the price doubles.
Buy it for turn efficiency, not for benchmark ceilings. On long agent runs, finishing in half the turns beats a model that scores two points higher and takes twice as many round trips.
Released August 12, 2026, succeeding Grok 4.5. Long-context billing is a cliff, not a ramp: at 200K tokens and above the whole request is charged at $4/$12. DeepSWE 65.9%, CursorBench 3.2 70.8%, FrontierCode 1.1 Extended 61.3%, Terminal-Bench 3.0 26.5%, APEX-Agents 57.5%.
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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. Grok 4.6 is the better pick when your work is mostly long-running agents and multi-step codebase work. Neither is universally "better": Claude Fable 5.1 is aimed at frontier agentic coding and long-horizon autonomous work, Grok 4.6 at long-running agents and multi-step codebase work.
Grok 4.6 is cheaper at $2/1M input and $6/1M output. Claude Fable 5.1 costs $10/1M input and $50/1M output.
Claude Fable 5.1 has the larger context window at 1M tokens vs Grok 4.6's 500K. For large document analysis, Claude Fable 5.1 is the stronger pick.
Claude Fable 5.1 is better for coding with a score of 100 vs Grok 4.6's 86 (out of 100). Claude Fable 5.1 is the overall coding leader in this directory at 100/100.
Grok 4.6 is faster with a fast speed rating (score: 4) 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 Grok 4.6 instead.
No published SWE-bench Verified or SWE-bench Pro figure, so it cannot be compared directly on the standard coding leaderboard. GPT-5.6 Sol Max beats it on DeepSWE v1.1 and Terminal-Bench 3.0. Prompts of 200K tokens or more are billed at $4/$12 across the entire request, not just the overage. Avoid it if you need a published SWE-bench score to justify the pick, or your prompts routinely cross 200K tokens where the price doubles. Against Claude Fable 5.1 specifically, the gap shows up most on coding (100 vs 86).
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); Grok 4.6 runs $32.00 (at $2/1M in and $6/1M out). That is a $168.00/month difference — Grok 4.6 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 Grok 4.6 handling long-running agents and multi-step codebase work. Routing high-volume, low-stakes calls to Grok 4.6 at $2/1M and reserving Claude Fable 5.1 for the hard cases is usually the cheapest arrangement that does not cost you quality.