Claude Fable 5.1 is the strongest alternative to GPT-6 Astra — it matches it on coding (100/100) at $10/1M input (GPT-6 Astra costs $10/1M). Claude Opus 4.8 is the budget swap: $5/1M input is 50% cheaper. Kimi K3 is the top open-weight option if you want a model you can self-host.
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.
Llama 3.2 1B Instruct is the lower-cost option to start with when you still need useful output at scale.
GPT-6 Astra is the better pick when response speed matters more than maximum reasoning depth.
Claude Fable 5.1 matches GPT-6 Astra on coding (100/100) at $10/1M input tokens.
Claude Opus 4.8 cuts input cost by 50% ($5 vs $10/1M) while scoring 100/100 on coding.
Kimi K3 is open-weight — self-host it or run it via low-cost API providers at $3/1M input.
Choose Claude Fable 5.1 when you want the closest overall replacement — it targets frontier agentic coding, long-horizon autonomous work, and agentic scientific research.
Choose Claude Opus 4.8 when token volume matters more than peak quality — it is 50% cheaper on input.
Staying with OpenAI? GPT-5.6 Sol is the strongest in-house switch at $2/1M input.
Switch the scoring lens to see whether the top answer changes when you care more about cost, speed, or long-document work.
OpenAI / Premium / Sep 4, 2026
OpenAI's frontier answer to Fable 5.1 — computer-use and agentic-coding leader at $10/$50.
Ranks models by the broadest mix of coding, writing, research, and long-context usefulness.
You are cost-sensitive or latency-bound — GPT-5.6 Sol is a fifth of the price — or you need it today in an Enterprise workspace, where it is off by default, or for offensive-security work, which it refuses outside OpenAI Daybreak.
The fastest way to see where the recommendation shifts when your priority changes.
OpenAI's frontier answer to Fable 5.1 — computer-use and agentic-coding leader at $10/$50.
New frontier leader — better than Fable 5 on every published benchmark, and cheaper to run.
Best value premium coder — frontier-grade at half of Fable 5's price.
Closest Chinese challenger to the frontier — #4 overall on intelligence.
Best OpenAI flagship — leads terminal coding and agentic browsing.
New global #1 — 80.3% SWE-Bench Pro, the most capable model generally available.
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-6 AstraOpenAI | $10.00/1M | $50.00/1M | $200 | 1.1M tokens | Deliberate | 100 | 97 | 100 |
| Claude Opus 4.8Anthropic | $5.00/1M | $25.00/1M | $100 | 1M tokens | Deliberate | 100 | 96 | 98 |
| Kimi K3Moonshot | $3.00/1M | $15.00/1M | $60 | 1M tokens | Deliberate | 96 | 90 | 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.
OpenAI's September 3, 2026 frontier release — the first GPT-6 model and OpenAI's answer to Claude Fable 5.1 two days earlier. State of the art on computer use (OSWorld 2.0 72.6% in ~47% less time than GPT-5.6 Sol), agentic coding (Terminal-Bench 4.0 57.9%), and frontier math (FrontierMath Tier 4 97.6%). $10/$50 per 1M tokens, 1.05M context, 128K output, knowledge cutoff April 30, 2026.
You are cost-sensitive or latency-bound — GPT-5.6 Sol is a fifth of the price — or you need it today in an Enterprise workspace, where it is off by default, or for offensive-security work, which it refuses outside OpenAI Daybreak.
The new computer-use and agentic-coding ceiling, and OpenAI's first model priced like a Mythos-class Claude. Astra beats Claude Fable 5.1 on Terminal-Bench 4.0 (57.9% vs 55.8%), Terminal-Bench Science (64.6% vs 52.6%) and FrontierMath Tier 4 (97.6% vs 87.8%), and it is the only model with a credible OSWorld 2.0 result above 70%. It loses to Fable 5.1 on Humanity's Last Exam and on Artificial Analysis's index, costs five times GPT-5.6 Sol, and ships without a SWE-bench number. If your work is computer use, browser agents or math, it is the pick; for everyday coding at scale, Sol at $2/$10 remains the value default.
Released September 3, 2026. API ID gpt-6-astra; rolling out over the coming days to ChatGPT Plus, Pro, Business and Enterprise (usage inside existing allowances; GPT-6 Astra Pro for Pro/Business/Enterprise; Enterprise off by default), the OpenAI API, Microsoft Azure and Amazon Bedrock. Standard API pricing $10/$50 per 1M tokens; Fast mode is up to 2x speed at 2x price; cache reads and writes have separate rates. Model docs list 1,050,000 context, 128,000 max output, knowledge cutoff April 30, 2026, reasoning efforts up to 'max'. Published launch numbers (Astra / GPT-5.6 Sol / Fable 5.1 / Opus 5): OSWorld 2.0 72.6 / 65.7 / — / 70.2; Terminal-Bench 4.0 57.9 / 37.3 / 55.8 / 52.3; Terminal-Bench Science 0.1 64.6 / 22.4 / 52.6 / 30.0; FrontierMath Tier 4 v2 97.6 / 83.0 / 87.8 / 73.2; GPQA Diamond 96.0 / 94.6 / 93.7 / 93.7; Humanity's Last Exam w/ tools 57.2 / — / 65.0 / 63.6; AutomationBench 41.4 / 18.1 / 31.4 / 26.9; DeepSWE v1.1 74.1 / 72.7 / 67.4 / 73.7; ARC-AGI-2 95.0 / 92.5 / 90.0 / 90.4; ARC-AGI-3 99.9 (OpenAI responses-API harness; ARC Prize's stateless runs score far lower) / 7.8 / — / 30.2; ExploitBench 100.0 / 78.5 / — / 70; SRE-Bench 88.0 / 55.9; Artificial Analysis Intelligence Index v4.1.1 61.2 / 60.9 / 65.7 / 63.1. Meets the Critical threshold for cybersecurity under OpenAI's Preparedness Framework; advanced cyber workflows gated behind OpenAI Daybreak. All figures from OpenAI's launch post and model docs, verified September 4, 2026.
Anthropic's newest Opus flagship — 69.2% SWE-Bench Pro, 88.6% SWE-Bench Verified, 1890 Arena Elo (121 pts ahead of GPT-5.5), and native parallel subagents. Same $5/$25 price as Opus 4.7.
You need low-latency responses, image generation, or a workflow locked to OpenAI tooling.
The best value at the premium tier now that Claude Fable 5 leads on raw capability. 69.2% SWE-Bench Pro, 1890 Elo, and built-in parallel subagents at $5/$25 — half the price of Fable 5. The smart default for serious coding when you don't need the absolute frontier.
Launched May 27, 2026. Available on Claude API, AWS Bedrock, Google Vertex AI, Microsoft Foundry, and GitHub Copilot. Fast mode available at $10/$50 per 1M tokens.
Moonshot's 2.8-trillion-parameter multimodal reasoning flagship with always-on thinking — the largest open-weight model ever released and the closest Chinese challenger to the Western frontier.
You need fast responses or predictable output costs — always-on thinking burns tokens.
The first Chinese model to genuinely crowd the Western frontier — #4 on aggregate intelligence ahead of Opus 4.8. The always-on thinking makes it slow and output-heavy, so cost per task runs above the sticker price. A serious Opus-class alternative if latency isn't critical.
Released July 16, 2026; open weights July 26. Cache-hit input $0.30/1M. Subscriptions: Adagio (free) to Vivace $199/mo; full 1M context only on Allegro ($99) and up. New signups paused July 19 near GPU capacity, reopening in batches.
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Claude Fable 5.1 is the strongest overall alternative. It scores 100/100 on coding (GPT-6 Astra: 100/100) and costs $10/1M input vs $10/1M. New frontier leader — better than Fable 5 on every published benchmark, and cheaper to run.
Claude Opus 4.8 at $5/1M input — 50% cheaper than GPT-6 Astra's $10/1M. It scores 100/100 on coding, so expect a quality step down on the hardest tasks.
Yes — Kimi K3 is the strongest open-weight replacement for GPT-6 Astra, scoring 96/100 on coding against GPT-6 Astra's 100/100. You can self-host it or run it through hosted APIs at $3/1M input (GPT-6 Astra costs $10/1M), with no per-seat subscription. Self-hosting trades the licence saving for infrastructure you have to run, so it pays off at sustained volume rather than for occasional use.
GPT-5.6 Sol — same provider, same API surface, $2/1M input vs $10/1M. Best OpenAI flagship — leads terminal coding and agentic browsing.
The new computer-use and agentic-coding ceiling, and OpenAI's first model priced like a Mythos-class Claude.