Claude Fable 5 vs Claude Opus 4.8
Claude Fable 5 (2026) and Claude Opus 4.8 (2026) are frontier-tier reasoning models from Anthropic. Claude Fable 5 ships a 1m-token context window, while Claude Opus 4.8 ships a 1m-token context window. On SWE-bench Verified, Claude Fable 5 leads by 7.4 pts. On pricing, Claude Opus 4.8 costs $5/1M 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.
Claude Opus 4.8 is ~100% cheaper at $5/1M; pay for Claude Fable 5 only for vision-heavy evaluation.
Decision scorecard
Local evidence first| Signal | Claude Fable 5 | Claude Opus 4.8 |
|---|---|---|
| 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 | $50/1M tokens | $25/1M tokens |
| Provider routes | 4 tracked | 6 tracked |
| Shared benchmarks | SWE-bench Verified leader | 3 rows |
Decision tradeoffs
- Claude Fable 5 holds a shared-benchmark lead on SWE-bench Verified, ahead by 7.4 points.
- Local decision data tags Claude Fable 5 for Coding, RAG, and Agents.
- Claude Opus 4.8 has the lower cheapest tracked output price at $25/1M tokens.
- Claude Opus 4.8 has broader tracked provider coverage for fallback and procurement flexibility.
- Claude Opus 4.8 uniquely exposes Code execution, Computer use, and Parallel agents in local model data.
- Local decision data tags Claude Opus 4.8 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
Claude Opus 4.8
$10,250
Cheapest tracked route/tier: Anthropic
Estimated monthly gap: $10,250. 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 Opus 4.8 is $25/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Claude Opus 4.8 adds Code execution, Computer use, and Parallel agents in local capability data.
- Provider overlap exists on Anthropic, AWS Bedrock, and GCP Vertex AI; start route-level A/B tests there.
- Claude Fable 5 is $25/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Code execution, Computer use, and Parallel agents before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-06-09 | 2026-05-28 |
| Context window | 1m | 1m |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | - | 2026-01 |
Pricing and availability
| Pricing attribute | Claude Fable 5 | Claude Opus 4.8 |
|---|---|---|
| Input price | $10/1M tokens | $5/1M tokens |
| Output price | $50/1M tokens | $25/1M tokens |
| Providers |
Capabilities
| Capability | Claude Fable 5 | Claude Opus 4.8 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | Yes |
| IDE integration | No | No |
| Computer use | No | Yes |
| Parallel agents | No | Yes |
Benchmarks
| Benchmark | Claude Fable 5 | Claude Opus 4.8 |
|---|---|---|
| SWE-bench Verified | 96.0 | 88.6 |
| SWE-bench Pro | 80.3 | 69.2 |
| GDPval-AA | 1932.0 | 1890.0 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has Claude Fable 5 at 96 and Claude Opus 4.8 at 88.6, with Claude Fable 5 ahead by 7.4 points; SWE-bench Pro has Claude Fable 5 at 80.3 and Claude Opus 4.8 at 69.2, with Claude Fable 5 ahead by 11.1 points; GDPval-AA has Claude Fable 5 at 1932 and Claude Opus 4.8 at 1890, with Claude Fable 5 ahead by 42 points. The largest visible gap is 42 points on GDPval-AA, 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 differs most on code execution: Claude Opus 4.8. Both models share vision, multimodal input, reasoning mode, and function calling, 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 Claude Opus 4.8 lists $5/1M input and $25/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Claude Opus 4.8 lower by about $11 per million blended tokens. Availability is 4 providers versus 6, so concentration risk also matters.
Choose Claude Fable 5 when vision-heavy evaluation are central to the workload. Choose Claude Opus 4.8 when coding workflow support, lower input-token cost, and broader provider choice 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 Claude Opus 4.8?
Claude Fable 5 supports 1m tokens, while Claude Opus 4.8 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 Claude Opus 4.8?
Claude Opus 4.8 is cheaper on tracked token pricing. Claude Fable 5 costs $10/1M input and $50/1M output tokens. Claude Opus 4.8 costs $5/1M input and $25/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Fable 5 or Claude Opus 4.8 open source?
Claude Fable 5 is listed under Proprietary. Claude Opus 4.8 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 Claude Opus 4.8?
Both Claude Fable 5 and Claude Opus 4.8 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 Claude Opus 4.8?
Both Claude Fable 5 and Claude Opus 4.8 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 Claude Opus 4.8?
Claude Fable 5 is available on Anthropic, AWS Bedrock, GCP Vertex AI, and Microsoft Foundry. Claude Opus 4.8 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: 2026-06-09. Data sourced from public model cards and provider documentation.