Claude Fable 5 vs Gemini 3.1 Pro

Anthropic · US  |  Google · US · Updated June 2026

Quick verdict

Pick Claude Fable 5 for the hardest reasoning and most complex problems or long-horizon, multi-step agentic work. Pick Gemini 3.1 Pro for full multimodal input — text, image, audio and video in one 1m-token window or long video and document analysis. On a tight budget at scale, Gemini 3.1 Pro is the value pick.

Claude Fable 5 (Anthropic) and Gemini 3.1 Pro (Google) are two of the models people most often weigh against each other in 2026. Claude Fable 5 is anthropic's top public Mythos-class model and its most capable yet, though tier access was temporarily suspended in June 2026 under a US export-control directive. Gemini 3.1 Pro is a 1M-token multimodal workhorse — huge breadth across text, image, audio and video, but recall fades deep in the window. They diverge most on price and context window — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecClaude Fable 5Gemini 3.1 Pro
ProviderAnthropic (US) Google (US)
ReleasedJune 9, 2026 February 19, 2026
Context window1M (~1,500 pages) 1M (~1,573 pages)
Price (in/out)$10/$50 per 1M tokens $2/$12 per 1M tokens
Open weight?No — API only No — API only
Modalitiestext, image, code text, image, audio, video, code
SWE-Bench VerifiedNot published Not published
MRCR v2 @ 1MNot published 26.3%

Who wins what

The hardest reasoning and most complex problems

Claude Fable 5

Anthropic's top public Mythos-class model and its most capable yet, though tier access was temporarily suspended in June 2026 under a US export-control directive — and it is the newer of the two.

Long-horizon, multi-step agentic work

Claude Fable 5

Claude Fable 5 lists long-horizon, multi-step agentic work among its strengths; Gemini 3.1 Pro does not.

Frontier-level analysis and research

Claude Fable 5

Claude Fable 5 lists frontier-level analysis and research among its strengths; Gemini 3.1 Pro does not.

Full multimodal input — text, image, audio and video in one 1M-token window

Gemini 3.1 Pro

A 1M-token multimodal workhorse — huge breadth across text, image, audio and video, but recall fades deep in the window — and it runs cheaper at $2/$12 per 1M tokens.

Long video and document analysis

Gemini 3.1 Pro

Gemini 3.1 Pro lists long video and document analysis among its strengths; Claude Fable 5 does not.

Agentic reasoning (high ARC-AGI-2)

Gemini 3.1 Pro

Gemini 3.1 Pro lists agentic reasoning (high ARC-AGI-2) among its strengths; Claude Fable 5 does not.

Lowest cost at scale

Gemini 3.1 Pro

At $2/$12 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Which should you pick?

A cost-sensitive startup shipping high volume

Gemini 3.1 Pro

At $2/$12 per 1M tokens it undercuts Claude Fable 5, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

Gemini 3.1 Pro

Larger 1M window fits more in one prompt.

Anyone whose priority is the hardest reasoning and most complex problems

Claude Fable 5

It is specifically built for that.

Anyone whose priority is full multimodal input — text, image, audio and video in one 1m-token window

Gemini 3.1 Pro

That is its strongest area.

Claude Fable 5: where it fits

Anthropic's top public Mythos-class model and its most capable yet, though tier access was temporarily suspended in June 2026 under a US export-control directive. Released June 9, 2026 by Anthropic, it is built for the hardest reasoning and most complex problems, long-horizon, multi-step agentic work, frontier-level analysis and research, and work where maximum capability outweighs cost.

Its trade-offs are real: highest price in the Claude lineup, and tier access was temporarily suspended in June 2026 under a US export-control directive. At $10 in / $50 out per million tokens, it sits in the premium price band.

Gemini 3.1 Pro: where it fits

A 1M-token multimodal workhorse — huge breadth across text, image, audio and video, but recall fades deep in the window. Released February 19, 2026 by Google, it is built for full multimodal input — text, image, audio and video in one 1M-token window, long video and document analysis, agentic reasoning (high ARC-AGI-2), and broad multimodal understanding across formats.

Its trade-offs: long-context recall drops sharply past 256K (26.3% on MRCR v2 at 1M), premium price per token at $2/$12, and superseded within Google's own line by the newer 3.5/3.6 Flash releases for cost-sensitive work. At $2 in / $12 out per million tokens, it sits in the mid price band.

The bottom line for this matchup

Claude Fable 5 and Gemini 3.1 Pro overlap enough that the right pick depends on your specific job. Gemini 3.1 Pro costs less per token; Gemini 3.1 Pro holds the larger context; and each leads in its own area — Claude Fable 5 for the hardest reasoning and most complex problems, Gemini 3.1 Pro for full multimodal input — text, image, audio and video in one 1m-token window. Rather than crowning one, run the same hard task through both once and let the results decide.

Want both Claude Fable 5 and Gemini 3.1 Pro without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.

See pricing

Frequently asked questions

Is Claude Fable 5 or Gemini 3.1 Pro better for coding?

Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Claude Fable 5 leans toward the hardest reasoning and most complex problems while Gemini 3.1 Pro leans toward full multimodal input — text, image, audio and video in one 1m-token window, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, Claude Fable 5 or Gemini 3.1 Pro?

Gemini 3.1 Pro is cheaper — $10/$50 per 1M tokens vs $2/$12 per 1M tokens, roughly 5× apart on input.

Which has the bigger context window?

Effectively neither — 1M vs 1M is a difference of a few percent. Remember advertised ≠ usable: recall typically degrades before the ceiling.

Can I use both Claude Fable 5 and Gemini 3.1 Pro together?

Yes — a multi-model platform like LumiChats gives you Claude Fable 5, Gemini 3.1 Pro and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.

Which is newer, Claude Fable 5 or Gemini 3.1 Pro?

Claude Fable 5 — released June 9, 2026, about 4 months after Gemini 3.1 Pro.

Related comparisons

Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.