Claude Fable 5 vs Grok 4.3
Claude Fable 5 (2026) and Grok 4.3 (2026) are frontier-tier reasoning models from Anthropic and xAI. Claude Fable 5 ships a 1m-token context window, while Grok 4.3 ships a 1m-token context window. On pricing, Claude Fable 5 costs $10/1M input tokens; Grok 4.3 ranges from $1.25 to $2.50/1M input tokens by tier. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Claude Fable 5 is safer overall; choose Grok 4.3 when vision-heavy evaluation matters.
Decision scorecard
Local evidence first| Signal | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | RAG, Agents, and Long context |
| Context window | 1m | 1m |
| Cheapest output | $50/1M tokens | $2.50/1M tokens |
| Provider routes | 4 tracked | 4 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Local decision data tags Claude Fable 5 for Coding, RAG, and Agents.
- Grok 4.3 has the lower cheapest tracked output price at $2.50/1M tokens.
- Local decision data tags Grok 4.3 for RAG, Agents, and Long context.
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
Grok 4.3
$1,625
Cheapest tracked route/tier: xAI Console
Estimated monthly gap: $18,875. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Microsoft Foundry; start route-level A/B tests there.
- Grok 4.3 is $47.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Provider overlap exists on Microsoft Foundry; start route-level A/B tests there.
- Claude Fable 5 is $47.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-06-09 | 2026-05-06 |
| Context window | 1m | 1m |
| Parameters | — | ~0.5T |
| Architecture | decoder only | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | - | 2024-11 |
Pricing and availability
| Pricing attribute | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| Input price | $10/1M tokens |
|
| Output price | $50/1M tokens |
|
| Providers |
Capabilities
| Capability | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint is close: both models cover vision, multimodal input, reasoning mode, function calling, and tool use. That makes context budget, benchmark fit, and provider maturity more important than a simple checklist. If your application depends on one integration detail, verify it against the provider route you plan to use, not just the base model listing.
For cost, Claude Fable 5 lists $10/1M input and $50/1M output tokens on the cheapest tracked provider, while Grok 4.3 lists tiered pricing: 0-200,001t is $1.25/1M input and $2.50/1M output; 200,001t+ is $2.50/1M input and $5/1M output. A 70/30 input-output blend puts Grok 4.3 lower by about $20.38 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 4 providers versus 4, so concentration risk also matters.
Choose Claude Fable 5 when vision-heavy evaluation are central to the workload. Choose Grok 4.3 when vision-heavy evaluation and lower cheapest-tier input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Claude Fable 5 or Grok 4.3?
Claude Fable 5 supports 1m tokens, while Grok 4.3 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 Grok 4.3?
Claude Fable 5 lists $10/1M input and $50/1M output tokens on the cheapest tracked provider. Grok 4.3 lists tiered pricing: 0-200,001t is $1.25/1M input and $2.50/1M output; 200,001t+ is $2.50/1M input and $5/1M output. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is Claude Fable 5 or Grok 4.3 open source?
Claude Fable 5 is listed under Proprietary. Grok 4.3 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 Grok 4.3?
Both Claude Fable 5 and Grok 4.3 expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Claude Fable 5 or Grok 4.3?
Both Claude Fable 5 and Grok 4.3 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 Grok 4.3?
Claude Fable 5 is available on Anthropic, AWS Bedrock, GCP Vertex AI, and Microsoft Foundry. Grok 4.3 is available on xAI Console, OpenRouter, Microsoft Foundry, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-09. Data sourced from public model cards and provider documentation.