Claude Fable 5.2 vs Claude Sonnet 5.5
Claude Fable 5.2 (2026) and Claude Sonnet 5.5 (2026) are frontier-tier reasoning models from Anthropic. Both ship a 1M-token context window. On SWE-bench Pro, Claude Fable 5.2 leads by 11.7 pts. On pricing, Claude Sonnet 5.5 costs $2/1M input tokens versus $8/1M 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.
Claude Sonnet 5.5 is ~300% cheaper at $2/1M; pay for Claude Fable 5.2 only for vision-heavy evaluation.
Decision scorecard
Local evidence first| Signal | Claude Fable 5.2 | Claude Sonnet 5.5 |
|---|---|---|
| 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 | Coding, RAG, and Agents |
| Context window | 1M | 1M |
| Cheapest output | $40/1M tokens | $10/1M tokens |
| Provider routes | 5 tracked | 5 tracked |
| Shared benchmarks | SWE-bench Pro leader | 7 shared |
Decision tradeoffs
- Claude Fable 5.2 holds a shared-benchmark lead on SWE-bench Pro, ahead by 11.7 points.
- Local decision data tags Claude Fable 5.2 for Coding, RAG, and Agents.
- Claude Sonnet 5.5 holds a shared-benchmark lead on CursorBench, ahead by 2.3 points.
- Claude Sonnet 5.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Claude Sonnet 5.5 has the lower cheapest tracked output price at $10/1M tokens.
- Local decision data tags Claude Sonnet 5.5 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 5.2
$16,400
Cheapest tracked route/tier: Anthropic
Claude Sonnet 5.5
$4,100
Cheapest tracked route/tier: Anthropic
Estimated monthly gap: $12,300. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Anthropic, AWS Bedrock, and GCP Vertex AI; start route-level A/B tests there.
- Claude Sonnet 5.5 is $30/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Provider overlap exists on Anthropic, AWS Bedrock, and GCP Vertex AI; start route-level A/B tests there.
- Claude Fable 5.2 is $30/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-11-09 | 2026-09-28 |
| Context window | 1M | 1M |
| Parameters | — | — |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Restricted | Restricted |
| Knowledge cutoff | 2026-06 | 2026-06 |
Pricing and availability
| Pricing attribute | Claude Fable 5.2 | Claude Sonnet 5.5 |
|---|---|---|
| Input price | $8/1M tokens | $2/1M tokens |
| Output price | $40/1M tokens | $10/1M tokens |
| Providers |
Capabilities
| Capability | Claude Fable 5.2 | Claude Sonnet 5.5 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| JSON / 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
| Benchmark | Claude Fable 5.2 | Claude Sonnet 5.5 |
|---|---|---|
| SWE-bench Pro | 93.0 | 81.3 |
| Terminal-Bench 4.0 | 67.6 | 61.8 |
| CursorBench | 60.0 | 55.5 |
| CursorBench | 53.2 | 55.5 |
| CursorBench | 56.9 | 55.5 |
| CursorBench | 56.3 | 55.5 |
| CursorBench | 54.8 | 55.5 |
Deep dive
On shared benchmark coverage, SWE-bench Pro has Claude Fable 5.2 at 93 and Claude Sonnet 5.5 at 81.3, with Claude Fable 5.2 ahead by 11.7 points; Terminal-Bench 4.0 has Claude Fable 5.2 at 67.6 and Claude Sonnet 5.5 at 61.8, with Claude Fable 5.2 ahead by 5.8 points; CursorBench has Claude Fable 5.2 at 60 and Claude Sonnet 5.5 at 55.5, with Claude Fable 5.2 ahead by 4.5 points. The largest visible gap is 11.7 points on SWE-bench Pro, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint is close: both models cover vision, multimodal input, reasoning mode, JSON / Tool use, and JSON / 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 5.2 lists $8/1M input and $40/1M output tokens on the cheapest listed provider, while Claude Sonnet 5.5 lists $2/1M input and $10/1M output tokens on the cheapest listed provider. A 70/30 input-output blend puts Claude Sonnet 5.5 lower by about $13.20 per million blended tokens. Availability is 5 providers versus 5, so concentration risk also matters.
Choose Claude Fable 5.2 when vision-heavy evaluation are central to the workload. Choose Claude Sonnet 5.5 when long-context analysis, 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.
FAQ
Which has a larger context window, Claude Fable 5.2 or Claude Sonnet 5.5?
Claude Sonnet 5.5 supports 1M tokens, while Claude Fable 5.2 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 5.2 or Claude Sonnet 5.5?
Claude Sonnet 5.5 is cheaper on listed token pricing. Claude Fable 5.2 costs $8/1M input and $40/1M output tokens. Claude Sonnet 5.5 costs $2/1M input and $10/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Fable 5.2 or Claude Sonnet 5.5 open source?
Claude Fable 5.2 is listed under Proprietary. Claude Sonnet 5.5 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 5.2 or Claude Sonnet 5.5?
Both Claude Fable 5.2 and Claude Sonnet 5.5 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 5.2 or Claude Sonnet 5.5?
Both Claude Fable 5.2 and Claude Sonnet 5.5 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 5.2 and Claude Sonnet 5.5?
Claude Fable 5.2 is available on Anthropic, AWS Bedrock, GCP Vertex AI, OpenRouter, and Vercel AI Gateway. Claude Sonnet 5.5 is available on Anthropic, AWS Bedrock, GCP Vertex AI, Microsoft Foundry, and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-11-09. Data sourced from public model cards and provider documentation.