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 largest mainstream production context (2m) 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 2M-token multimodal workhorse — huge breadth, 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
Price: Gemini 3.1 Pro is about 5× cheaper on input ($2/$12 per 1M tokens vs $10/$50 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
Context window: Gemini 3.1 Pro holds 2× more — 2M (~3,000 pages) vs 1M (~1,500 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
Recency: Claude Fable 5 is the newer model by about 4 months (released June 9, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Fable 5
Gemini 3.1 Pro
Provider
Anthropic (US)
Google (US)
Released
June 9, 2026
February 19, 2026
Context window
1M (~1,500 pages)
2M (~3,000 pages)
Price (in/out)
$10/$50 per 1M tokens
$2/$12 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, audio, video, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
26.3%
Who wins what
The hardest reasoning and most complex problems: Claude Fable 5 — A core design strength of Claude Fable 5.
Long-horizon, multi-step agentic work: Claude Fable 5 — A core design strength of Claude Fable 5.
Frontier-level analysis and research: Claude Fable 5 — A core design strength of Claude Fable 5.
Largest mainstream production context (2M): Gemini 3.1 Pro — A core design strength of Gemini 3.1 Pro.
Long video and document analysis: Gemini 3.1 Pro — A core design strength of Gemini 3.1 Pro.
Agentic reasoning (high ARC-AGI-2): Gemini 3.1 Pro — A core design strength of Gemini 3.1 Pro.
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.
Largest single-prompt input: Gemini 3.1 Pro — Its 2M window is about 2× larger, fitting roughly 3,000 pages in one prompt.
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 2M 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 largest mainstream production context (2m): 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 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window. Released February 19, 2026 by Google, it is built for largest mainstream production context (2M), long video and document analysis, agentic reasoning (high ARC-AGI-2), and multimodal understanding.
Its trade-offs: long-context recall drops sharply past 256K, and premium price per token. 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 largest mainstream production context (2m). Rather than crowning one, run the same hard task through both once and let the results decide.
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 largest mainstream production context (2m), 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?
Gemini 3.1 Pro — 2M vs 1M, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
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.
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 largest mainstream production context (2m) 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 2M-token multimodal workhorse — huge breadth, 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
▸Price: Gemini 3.1 Pro is about 5× cheaper on input ($2/$12 per 1M tokens vs $10/$50 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
▸Context window: Gemini 3.1 Pro holds 2× more — 2M (~3,000 pages) vs 1M (~1,500 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
▸Recency: Claude Fable 5 is the newer model by about 4 months (released June 9, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Fable 5
Gemini 3.1 Pro
Provider
Anthropic (US)
Google (US)
Released
June 9, 2026
February 19, 2026
Context window
1M (~1,500 pages)
2M (~3,000 pages)
Price (in/out)
$10/$50 per 1M tokens
$2/$12 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, audio, video, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
26.3%
Who wins what
The hardest reasoning and most complex problems
Claude Fable 5
A core design strength of Claude Fable 5.
Long-horizon, multi-step agentic work
Claude Fable 5
A core design strength of Claude Fable 5.
Frontier-level analysis and research
Claude Fable 5
A core design strength of Claude Fable 5.
Largest mainstream production context (2M)
Gemini 3.1 Pro
A core design strength of Gemini 3.1 Pro.
Long video and document analysis
Gemini 3.1 Pro
A core design strength of Gemini 3.1 Pro.
Agentic reasoning (high ARC-AGI-2)
Gemini 3.1 Pro
A core design strength of Gemini 3.1 Pro.
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.
Largest single-prompt input
Gemini 3.1 Pro
Its 2M window is about 2× larger, fitting roughly 3,000 pages in one prompt.
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 2M 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 largest mainstream production context (2m)
→ 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 2M-token multimodal workhorse — huge breadth, but recall fades deep in the window. Released February 19, 2026 by Google, it is built for largest mainstream production context (2M), long video and document analysis, agentic reasoning (high ARC-AGI-2), and multimodal understanding.
Its trade-offs: long-context recall drops sharply past 256K, and premium price per token. 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 largest mainstream production context (2m). 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.
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 largest mainstream production context (2m), 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?
Gemini 3.1 Pro — 2M vs 1M, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.
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.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.