Claude Mythos Preview vs Claude Sonnet 4.6
Claude Mythos Preview (2026) and Claude Sonnet 4.6 (2026) are frontier-tier reasoning models from Anthropic. Claude Mythos Preview ships a 1M-token context window, while Claude Sonnet 4.6 ships a 1M-token context window. On SWE-bench Verified, Claude Mythos Preview leads by 14.3 pts. On pricing, Claude Sonnet 4.6 costs $3/1M input tokens versus $25/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Claude Sonnet 4.6 is ~733% cheaper at $3/1M; pay for Claude Mythos Preview only for coding workflow support.
Decision scorecard
Local evidence first| Signal | Claude Mythos Preview | Claude Sonnet 4.6 |
|---|---|---|
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1M | 1M |
| Cheapest output | $125/1M tokens | $15/1M tokens |
| Provider routes | 2 tracked | 5 tracked |
| Shared benchmarks | SWE-bench Verified leader | 3 rows |
Decision tradeoffs
- Claude Mythos Preview leads the largest shared benchmark signal on SWE-bench Verified by 14.3 points.
- Local decision data tags Claude Mythos Preview for Coding, RAG, and Agents.
- Claude Sonnet 4.6 has the lower cheapest tracked output price at $15/1M tokens.
- Claude Sonnet 4.6 has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Claude Sonnet 4.6 for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
Claude Mythos Preview
$51,250
Cheapest tracked route: Anthropic
Claude Sonnet 4.6
$6,150
Cheapest tracked route: OpenRouter
Estimated monthly gap: $45,100. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Anthropic and Microsoft Foundry; start route-level A/B tests there.
- Claude Sonnet 4.6 is $110/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Provider overlap exists on Anthropic and Microsoft Foundry; start route-level A/B tests there.
- Claude Mythos Preview is $110/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-07 | 2026-02-17 |
| Context window | 1M | 1M |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-12 | 2025-12 |
Pricing and availability
| Pricing attribute | Claude Mythos Preview | Claude Sonnet 4.6 |
|---|---|---|
| Input price | $25/1M tokens | $3/1M tokens |
| Output price | $125/1M tokens | $15/1M tokens |
| Providers |
Capabilities
| Capability | Claude Mythos Preview | Claude Sonnet 4.6 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
Benchmarks
| Benchmark | Claude Mythos Preview | Claude Sonnet 4.6 |
|---|---|---|
| SWE-bench Verified | 93.9 | 79.6 |
| Google-Proof Q&A | 94.6 | 89.9 |
| τ-bench | 89.2 | 87.5 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has Claude Mythos Preview at 93.9 and Claude Sonnet 4.6 at 79.6, with Claude Mythos Preview ahead by 14.3 points; Google-Proof Q&A has Claude Mythos Preview at 94.6 and Claude Sonnet 4.6 at 89.9, with Claude Mythos Preview ahead by 4.7 points; τ-bench has Claude Mythos Preview at 89.2 and Claude Sonnet 4.6 at 87.5, with Claude Mythos Preview ahead by 1.7 points. The largest visible gap is 14.3 points on SWE-bench Verified, 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, 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 Mythos Preview lists $25/1M input and $125/1M output tokens, while Claude Sonnet 4.6 lists $3/1M input and $15/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Claude Sonnet 4.6 lower by about $48.40 per million blended tokens. Availability is 2 providers versus 5, so concentration risk also matters.
Choose Claude Mythos Preview when coding workflow support are central to the workload. Choose Claude Sonnet 4.6 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 Mythos Preview or Claude Sonnet 4.6?
Claude Mythos Preview supports 1M tokens, while Claude Sonnet 4.6 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 Mythos Preview or Claude Sonnet 4.6?
Claude Sonnet 4.6 is cheaper on tracked token pricing. Claude Mythos Preview costs $25/1M input and $125/1M output tokens. Claude Sonnet 4.6 costs $3/1M input and $15/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Mythos Preview or Claude Sonnet 4.6 open source?
Claude Mythos Preview is listed under Proprietary. Claude Sonnet 4.6 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 Mythos Preview or Claude Sonnet 4.6?
Both Claude Mythos Preview and Claude Sonnet 4.6 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 Mythos Preview or Claude Sonnet 4.6?
Both Claude Mythos Preview and Claude Sonnet 4.6 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 Mythos Preview and Claude Sonnet 4.6?
Claude Mythos Preview is available on Anthropic and Microsoft Foundry. Claude Sonnet 4.6 is available on OpenRouter, Anthropic, AWS Bedrock, GCP Vertex AI, and Microsoft Foundry. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-16. Data sourced from public model cards and provider documentation.