Claude Fable 5.2 vs Gemini 4 Carbon vs Muse Ember: Which AI Model for Which Job?
Photo: Hippopx (public domain). Illustrative image.
Three frontier-class models arrived within days of each other in November 2026, and their prices span a factor of eighty. Anthropic’s Claude Fable 5.2 costs $8 per million input tokens. Google’s Gemini 4 Carbon costs $2 — until 30 November, when it doubles. Meta’s Muse Ember costs $0.10. Same 1-million-token context window on all three. Very different jobs. This comparison uses the figures each company published at launch, all of which FreshSynapse has already verified in its own coverage — and every benchmark below is the vendor’s own, not an independent finding.
The comparison at a glance
| Claude Fable 5.2 | Gemini 4 Carbon | Muse Ember | |
|---|---|---|---|
| Vendor | Anthropic | Meta | |
| Launched | 9 November 2026 | 28 October 2026; widely available 10 November | 9 November 2026 |
| Input price | $8 per million tokens | $2 per million (intro, to 30 Nov), then $4 | $0.10 per million |
| Output price | $40 per million tokens | $10 per million (intro, to 30 Nov), then $20 | $0.50 per million |
| Context window | 1 million tokens | 1 million tokens (shared by input, thinking and output) | 1 million tokens |
| Max output | 128,000 tokens | Not disclosed separately | 512,000 tokens |
| Headline benchmark | FrontierCode 2.0: 49.1% | Intelligence Index v5.0: 59 (model card) | Intelligence Index: 36; AutomationBench 37.8% |
| Access | Claude apps, API, AWS, Google Cloud, Azure | API, Gemini for business, AI Ultra subscribers | Meta Model API, Muse Code, Google Cloud, Oracle Cloud |
| Best for | Hard coding, science, cybersecurity | Long-horizon reasoning, research, verification | Repetitive agent work at volume |
Claude Fable 5.2: the heavyweight
Fable 5.2 is Anthropic’s most capable model, launched 9 November 2026 at $8 per million input tokens and $40 per million output — 20% cheaper than Fable 5.1. It scores 49.1% on FrontierCode 2.0, Anthropic’s own coding benchmark, against 32.4% for Fable 5.1 and 45.5% for Opus 5.5, and Anthropic says it generates responses up to 30% faster than its predecessor, with a fast mode at $16/$80 that runs up to 2.5 times faster. It takes a 1-million-token context and returns up to 128,000 tokens. Anthropic’s launch claims are the boldest of the three — around 1,000 agents building a bootable operating system in eight days, and formalising Fermat’s Last Theorem in about 30 hours — and they are Anthropic’s claims, not independent results. A second version, Mythos 5.2, is the same underlying model with tighter cyber and biology safeguards, available only to vetted organisations. If the job is genuinely hard — a large refactor, a scientific workflow, a security review — Fable is the model built for it, and the price is the price of that capability.
Gemini 4 Carbon: the long-horizon reasoner
Carbon is Google’s strongest model, announced 28 October 2026 and made widely available on 10 November. It builds on Gemini 4 Argon’s foundation with extra post-training for deep reasoning, extended verification and multi-step agent workflows. The model card reports 59 on Artificial Analysis’s Intelligence Index v5.0 against 50 for Argon, and 96.2% against 84.2% on the GraphWalks long-context test. The catch is the calendar: the $2/$10 introductory price ends on 30 November, doubling to $4/$20 from 1 December — and every processed token is billed, including thinking tokens, so Carbon’s habit of using more tokens to explore and verify harder problems shows up on the bill. Google itself says Argon remains the recommended option for most software-engineering and knowledge work. Carbon is also the hardest of the three to reach: in the Gemini app it is limited to Google AI Ultra subscribers, on a plan starting at $99.99 a month. For long research and verification tasks where the extra reasoning is worth paying for, Carbon earns its place; for routine coding, Google points you at Argon instead.
Muse Ember: the volume worker
Ember is Meta’s smallest and cheapest model, launched 9 November 2026 at $0.10 per million input tokens and $0.50 per million output, with cached input at $0.004. Meta says it matches Claude Haiku 5.5’s best score on Artificial Analysis’s Intelligence Index — 36 — at $0.14 per task against Haiku’s $0.41, about a third of the cost, and scored 37.8% on AutomationBench against Haiku’s 13.9%. It takes text, images, audio and video, holds a 1-million-token context and can return up to 512,000 tokens — the largest output of the three. The trade-off is knowledge: Artificial Analysis says Ember declines 64% of trivia-style questions. Meta does not pretend otherwise: Ember is the volume worker under Muse Wonder, the planner, and Muse Spark, the coder. It is API-only — no parameter count disclosed, no weights released. If the job is millions of small, well-specified calls — tool use, routing, extraction, coding subtasks — Ember does them at a price the other two cannot touch. As a general assistant, it would show its limits quickly.
The verdict
There is no best model here, only a best model for the job. Pick Fable 5.2 when the task is hard and the cost of getting it wrong exceeds the cost of the tokens — the flagship coding and science work. Pick Carbon when the task needs long, careful reasoning with verification, and compare it at the December price of $4/$20, not the November teaser. Pick Ember when the task is repetitive, well-specified and high-volume, and put a smarter model above it to plan and check. The pattern the three launches share is the real story: the price war has moved from the flagship to the whole stack, and the sensible setup is no longer one model — it is a planner, a reasoner and a worker, each priced for what it actually does. Before choosing any of them, run the same checks you would on any new tool — how to evaluate a new AI tool — and remember what an AI agent actually is: a model given a goal, a toolbox and permission to iterate, where the choice of model decides how far each iteration can go.
Sources
- FreshSynapse — “Anthropic Launches Claude Fable 5.2 and Mythos 5.2 at Lower Prices — Same Model, Two Safety Levels”: https://freshsynapse.com/articles/anthropic-claude-fable-mythos-5-2-2026-11-10/
- FreshSynapse — “Google’s Gemini 4 Carbon Is Out of the Lab and Into the Gemini App — for Ultra Subscribers”: https://freshsynapse.com/articles/google-gemini-4-carbon-available-2026-11-11/
- FreshSynapse — “Meta’s Muse Ember Is Its Smallest Model Yet — Haiku-Level Scores at a Third of the Cost”: https://freshsynapse.com/articles/meta-muse-ember-smallest-model-2026-11-10/
- FreshSynapse — “How to Evaluate a New AI Tool Before You Trust It”: https://freshsynapse.com/articles/how-to-evaluate-a-new-ai-tool/
- FreshSynapse — “What Is an AI Agent? A Plain-English Guide to How AI Agents Work”: https://freshsynapse.com/articles/what-is-an-ai-agent/
