Claude Fable 5 vs Gemini 3.1 Flash-Lite
Claude Fable 5 (2026) and Gemini 3.1 Flash-Lite (2026) are frontier reasoning models from Anthropic and Google DeepMind. Claude Fable 5 ships a 1m-token context window, while Gemini 3.1 Flash-Lite ships a 1.05m-token context window. On pricing, Gemini 3.1 Flash-Lite costs $0.25/1M input tokens versus $10/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Gemini 3.1 Flash-Lite is ~3900% cheaper at $0.25/1M; pay for Claude Fable 5 only for reasoning depth.
Decision scorecard
Local evidence first| Signal | Claude Fable 5 | Gemini 3.1 Flash-Lite |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | multimodal apps, tool-calling agents, and long-context analysis |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1m | 1.05m |
| Cheapest output | $50/1M tokens | $1.50/1M tokens |
| Provider routes | 4 tracked | 3 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- Claude Fable 5 has broader tracked provider coverage for fallback and procurement flexibility.
- Claude Fable 5 uniquely exposes Reasoning in local model data.
- Local decision data tags Claude Fable 5 for Coding, RAG, and Agents.
- Gemini 3.1 Flash-Lite has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Gemini 3.1 Flash-Lite has the lower cheapest tracked output price at $1.50/1M tokens.
- Gemini 3.1 Flash-Lite uniquely exposes Code execution in local model data.
- Local decision data tags Gemini 3.1 Flash-Lite for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Fable 5
$20,500
Cheapest tracked route/tier: Anthropic
Gemini 3.1 Flash-Lite
$575
Cheapest tracked route/tier: Google AI Studio
Estimated monthly gap: $19,925. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for Claude Fable 5 and Gemini 3.1 Flash-Lite; plan for SDK, billing, or endpoint changes.
- Gemini 3.1 Flash-Lite is $48.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning before moving production traffic.
- Gemini 3.1 Flash-Lite adds Code execution in local capability data.
- No overlapping tracked provider route is sourced for Gemini 3.1 Flash-Lite and Claude Fable 5; plan for SDK, billing, or endpoint changes.
- Claude Fable 5 is $48.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Code execution before moving production traffic.
- Claude Fable 5 adds Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-06-09 | 2026-05-07 |
| Context window | 1m | 1.05m |
| Parameters | — | — |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | - | 2025-01 |
Pricing and availability
| Pricing attribute | Claude Fable 5 | Gemini 3.1 Flash-Lite |
|---|---|---|
| Input price | $10/1M tokens | $0.25/1M tokens |
| Output price | $50/1M tokens | $1.50/1M tokens |
| Providers |
Capabilities
| Capability | Claude Fable 5 | Gemini 3.1 Flash-Lite |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
Deep dive
The capability footprint differs most on reasoning mode: Claude Fable 5 and code execution: Gemini 3.1 Flash-Lite. Both models share vision, multimodal input, function calling, and tool use, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Claude Fable 5 lists $10/1M input and $50/1M output tokens on the cheapest tracked provider, while Gemini 3.1 Flash-Lite lists $0.25/1M input and $1.50/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Gemini 3.1 Flash-Lite lower by about $21.38 per million blended tokens. Availability is 4 providers versus 3, so concentration risk also matters.
Choose Claude Fable 5 when reasoning depth and broader provider choice are central to the workload. Choose Gemini 3.1 Flash-Lite when coding workflow support, larger context windows, and lower input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions.
FAQ
Which has a larger context window, Claude Fable 5 or Gemini 3.1 Flash-Lite?
Gemini 3.1 Flash-Lite supports 1.05m tokens, while Claude Fable 5 supports 1m tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Claude Fable 5 or Gemini 3.1 Flash-Lite?
Gemini 3.1 Flash-Lite is cheaper on tracked token pricing. Claude Fable 5 costs $10/1M input and $50/1M output tokens. Gemini 3.1 Flash-Lite costs $0.25/1M input and $1.50/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Fable 5 or Gemini 3.1 Flash-Lite open source?
Claude Fable 5 is listed under Proprietary. Gemini 3.1 Flash-Lite is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Claude Fable 5 or Gemini 3.1 Flash-Lite?
Both Claude Fable 5 and Gemini 3.1 Flash-Lite expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for multimodal input, Claude Fable 5 or Gemini 3.1 Flash-Lite?
Both Claude Fable 5 and Gemini 3.1 Flash-Lite expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Claude Fable 5 and Gemini 3.1 Flash-Lite?
Claude Fable 5 is available on Anthropic, AWS Bedrock, GCP Vertex AI, and Microsoft Foundry. Gemini 3.1 Flash-Lite is available on Google AI Studio, OpenRouter, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-06-19. Data sourced from public model cards and provider documentation.