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Claude Fable 5 vs Gemini 3.1 Pro (preview)
Price, context window and capabilities side by side — read from the same catalog that meters your calls, not from a press release.
Gemini 3.1 Pro (preview) is 5.0x cheaper on input. Gemini 3.1 Pro (preview) is 4.2x cheaper on output. Gemini 3.1 Pro (preview) holds 1M tokens against 200K.
At a glance
Side by side
Anthropic
Anthropic's first Mythos-class model, the new flagship tier above Opus, tuned for the hardest reasoning and agentic work.
Google's newest Pro tier, shipped as a preview.
Specifications
Every difference we can measure
| Claude Fable 5 | Gemini 3.1 Pro (preview) | |
|---|---|---|
| Input price | $10/M | $2/M |
| Output price | $50/M | $12/M |
| Context window | 200K tokens | 1M tokens |
| Vision | Yes | Yes |
| Tool calling | Yes | Yes |
| Prompt caching | No | Yes |
| Long context | No | Yes |
A row appears only when we hold the fact for both models. Anything the provider has not published is left out rather than guessed, so an empty row is missing data and never a zero.
Verdict
Which to pick
Gemini 3.1 Pro counters with a giant context window and multimodal input; Fable 5 leads on deep reasoning and agentic reliability. Massive-context ingestion to Gemini, hardest-reasoning steps to Fable, same balance either way.
Keep looking
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FAQ
Frequently asked questions
What is the difference between Claude Fable 5 and Gemini 3.1 Pro (preview)?
Gemini 3.1 Pro (preview) is 5.0x cheaper on input. Gemini 3.1 Pro (preview) is 4.2x cheaper on output. Gemini 3.1 Pro (preview) holds 1M tokens against 200K. Only Gemini 3.1 Pro (preview) declares prompt caching. Only Gemini 3.1 Pro (preview) declares long context. Both run on the same endpoint and the same key here, so trying each is a one-line change to the model id.
Which is cheaper, Claude Fable 5 or Gemini 3.1 Pro (preview)?
Gemini 3.1 Pro (preview) is, on input tokens. Output usually dominates the bill on generative work, so check the output row above against your own ratio of prompt to completion before deciding.
Can I switch between Claude Fable 5 and Gemini 3.1 Pro (preview) without changing my code?
Yes. Both are OpenAI-compatible through one CompanyFabric key, so switching is the model string and nothing else — no second SDK, no second contract, one prepaid balance across both.
Do I have to choose?
No. Send companyfabric/auto and we route each request to the cheapest model that can serve it, which is how most people use both without deciding in advance.
One key. Every model. Exact prices.
Run Claude Fable 5 and Gemini 3.1 Pro (preview) on the same key and compare them on your own prompts. Free starter credits included, no subscription required.