LLM Reference

Claude Mythos Preview vs Qwen3.5-397B-A17B

Claude Mythos Preview (2026) and Qwen3.5-397B-A17B (2026) are frontier-tier reasoning models from Anthropic and Alibaba. Claude Mythos Preview ships a 1m-token context window, while Qwen3.5-397B-A17B ships a 262k-token context window. On SWE-bench Verified, Claude Mythos Preview leads by 17.7 pts. On pricing, Qwen3.5-397B-A17B costs $0.39/1M input tokens versus $25/1M 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.

Qwen3.5-397B-A17B is ~6310% cheaper at $0.39/1M; pay for Claude Mythos Preview only for coding workflow support.

Decision scorecard

Local evidence first
SignalClaude Mythos PreviewQwen3.5-397B-A17B
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsreasoning-heavy apps, multimodal apps, and tool-calling agents
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window1m262k
Cheapest output$125/1M tokens$2.34/1M tokens
Provider routes2 tracked4 tracked
Shared benchmarksSWE-bench Verified leader3 shared

Decision tradeoffs

Choose Claude Mythos Preview when...
  • Claude Mythos Preview holds a shared-benchmark lead on SWE-bench Verified, ahead by 17.7 points.
  • Claude Mythos Preview has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Claude Mythos Preview uniquely exposes Code execution in local model data.
  • Local decision data tags Claude Mythos Preview for Coding, RAG, and Agents.
Choose Qwen3.5-397B-A17B when...
  • Qwen3.5-397B-A17B has the lower cheapest tracked output price at $2.34/1M tokens.
  • Qwen3.5-397B-A17B has broader tracked provider coverage for fallback and procurement flexibility.
  • Local decision data tags Qwen3.5-397B-A17B 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.

Lower estimate Qwen3.5-397B-A17B

Claude Mythos Preview

$51,250

Cheapest tracked route/tier: Anthropic

Qwen3.5-397B-A17B

$897

Cheapest tracked route/tier: OpenRouter

Estimated monthly gap: $50,353. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Mythos Preview -> Qwen3.5-397B-A17B
  • No overlapping tracked provider route is sourced for Claude Mythos Preview and Qwen3.5-397B-A17B; plan for SDK, billing, or endpoint changes.
  • Qwen3.5-397B-A17B is $123/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for Code execution before moving production traffic.
Qwen3.5-397B-A17B -> Claude Mythos Preview
  • No overlapping tracked provider route is sourced for Qwen3.5-397B-A17B and Claude Mythos Preview; plan for SDK, billing, or endpoint changes.
  • Claude Mythos Preview is $123/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Claude Mythos Preview adds Code execution in local capability data.

Specs

Specification
Released2026-05-012026-02-16
Context window1m262k
Parameters—397B
ArchitectureDecoder OnlyMixture of Experts
LicenseProprietaryApache 2.0OSI-approved
OpennessProprietaryOpen source
Commercial useCommercial use: conditionalCommercial use: permitted
Knowledge cutoff2025-12-

Pricing and availability

Pricing attributeClaude Mythos PreviewQwen3.5-397B-A17B
Input price$25/1M tokens$0.39/1M tokens
Output price$125/1M tokens$2.34/1M tokens
Providers
AnthropicMicrosoft Foundry
OpenRouterTogether AIAlibaba Cloud PAI-EASNovita AI

Capabilities

CapabilityClaude Mythos PreviewQwen3.5-397B-A17B
VisionYesYes
MultimodalYesYes
ReasoningYesYes
Function callingYesYes
Tool useYesYes
Structured outputsYesYes
Code executionYesNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkClaude Mythos PreviewQwen3.5-397B-A17B
SWE-bench Verified93.976.2
Google-Proof Q&A94.689.3
τ-bench89.286.7

Deep dive

On shared benchmark coverage, SWE-bench Verified has Claude Mythos Preview at 93.9 and Qwen3.5-397B-A17B at 76.2, with Claude Mythos Preview ahead by 17.7 points; Google-Proof Q&A has Claude Mythos Preview at 94.6 and Qwen3.5-397B-A17B at 89.3, with Claude Mythos Preview ahead by 5.3 points; τ-bench has Claude Mythos Preview at 89.2 and Qwen3.5-397B-A17B at 86.7, with Claude Mythos Preview ahead by 2.5 points. The largest visible gap is 17.7 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 differs most on code execution: Claude Mythos Preview. 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 Mythos Preview lists $25/1M input and $125/1M output tokens on the cheapest tracked provider, while Qwen3.5-397B-A17B lists $0.39/1M input and $2.34/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Qwen3.5-397B-A17B lower by about $54.02 per million blended tokens. Availability is 2 providers versus 4, so concentration risk also matters.

Choose Claude Mythos Preview when coding workflow support and larger context windows are central to the workload. Choose Qwen3.5-397B-A17B when vision-heavy evaluation, 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 Qwen3.5-397B-A17B?

Claude Mythos Preview supports 1m tokens, while Qwen3.5-397B-A17B supports 262k 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 Qwen3.5-397B-A17B?

Qwen3.5-397B-A17B is cheaper on tracked token pricing. Claude Mythos Preview costs $25/1M input and $125/1M output tokens. Qwen3.5-397B-A17B costs $0.39/1M input and $2.34/1M output tokens. Provider discounts or batch pricing can still change the final bill.

Is Claude Mythos Preview or Qwen3.5-397B-A17B open source?

Claude Mythos Preview is listed under Proprietary. Qwen3.5-397B-A17B is listed under Apache 2.0. 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 Qwen3.5-397B-A17B?

Both Claude Mythos Preview and Qwen3.5-397B-A17B 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 Mythos Preview or Qwen3.5-397B-A17B?

Both Claude Mythos Preview and Qwen3.5-397B-A17B expose multimodal input. 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.

Where can I run Claude Mythos Preview and Qwen3.5-397B-A17B?

Claude Mythos Preview is available on Anthropic and Microsoft Foundry. Qwen3.5-397B-A17B is available on OpenRouter, Together AI, Alibaba Cloud PAI-EAS, and Novita AI. Provider coverage can affect latency, region availability, compliance posture, and fallback options.

Continue comparing

Model pages
Labs and families
Related comparisons

Popular comparisons for Claude Mythos Preview

Popular comparisons for Qwen3.5-397B-A17B

Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.