Claude Mythos Preview vs Mistral Large 3 675B Instruct
Claude Mythos Preview (2026) and Mistral Large 3 675B Instruct (2025) are frontier reasoning models from Anthropic and MistralAI. Claude Mythos Preview ships a 1M-token context window, while Mistral Large 3 675B Instruct ships a 128K-token context window. On τ-bench, Claude Mythos Preview leads by 19 pts. On pricing, Mistral Large 3 675B Instruct costs $0.5/1M input tokens versus $25/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Mistral Large 3 675B Instruct is ~4900% cheaper at $0.5/1M; pay for Claude Mythos Preview only for coding workflow support.
Decision scorecard
Local evidence first| Signal | Claude Mythos Preview | Mistral Large 3 675B Instruct |
|---|---|---|
| Decision fit | Coding, RAG, and Agents | RAG, Agents, and Long context |
| Context window | 1M | 128K |
| Cheapest output | $125/1M tokens | $1.5/1M tokens |
| Provider routes | 2 tracked | 4 tracked |
| Shared benchmarks | τ-bench leader | 1 rows |
Decision tradeoffs
- Claude Mythos Preview leads the largest shared benchmark signal on τ-bench by 19 points.
- Claude Mythos Preview has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Claude Mythos Preview uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Claude Mythos Preview for Coding, RAG, and Agents.
- Mistral Large 3 675B Instruct has the lower cheapest tracked output price at $1.5/1M tokens.
- Mistral Large 3 675B Instruct has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Mistral Large 3 675B Instruct for RAG, Agents, and Long context.
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
Mistral Large 3 675B Instruct
$775
Cheapest tracked route: AWS Bedrock
Estimated monthly gap: $50,475. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Microsoft Foundry; start route-level A/B tests there.
- Mistral Large 3 675B Instruct is $124/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- Provider overlap exists on Microsoft Foundry; start route-level A/B tests there.
- Claude Mythos Preview is $124/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Claude Mythos Preview adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-07 | 2025-12-01 |
| Context window | 1M | 128K |
| Parameters | — | 675B |
| Architecture | decoder only | decoder only |
| License | Proprietary | 1 |
| Knowledge cutoff | 2025-12 | - |
Pricing and availability
| Pricing attribute | Claude Mythos Preview | Mistral Large 3 675B Instruct |
|---|---|---|
| Input price | $25/1M tokens | $0.5/1M tokens |
| Output price | $125/1M tokens | $1.5/1M tokens |
| Providers |
Capabilities
| Capability | Claude Mythos Preview | Mistral Large 3 675B Instruct |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
Benchmarks
| Benchmark | Claude Mythos Preview | Mistral Large 3 675B Instruct |
|---|---|---|
| τ-bench | 89.2 | 70.2 |
Deep dive
On shared benchmark coverage, τ-bench has Claude Mythos Preview at 89.2 and Mistral Large 3 675B Instruct at 70.2, with Claude Mythos Preview ahead by 19 points. The largest visible gap is 19 points on τ-bench, 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 vision: Claude Mythos Preview, multimodal input: Claude Mythos Preview, reasoning mode: Claude Mythos Preview, function calling: Claude Mythos Preview, tool use: Claude Mythos Preview, and code execution: Claude Mythos Preview. Both models share structured outputs, 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, while Mistral Large 3 675B Instruct lists $0.5/1M input and $1.5/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Mistral Large 3 675B Instruct lower by about $54.20 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 Mistral Large 3 675B Instruct when provider fit, 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 Mistral Large 3 675B Instruct?
Claude Mythos Preview supports 1M tokens, while Mistral Large 3 675B Instruct supports 128K 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 Mistral Large 3 675B Instruct?
Mistral Large 3 675B Instruct is cheaper on tracked token pricing. Claude Mythos Preview costs $25/1M input and $125/1M output tokens. Mistral Large 3 675B Instruct costs $0.5/1M input and $1.5/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Mythos Preview or Mistral Large 3 675B Instruct open source?
Claude Mythos Preview is listed under Proprietary. Mistral Large 3 675B Instruct is listed under 1. 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 Mistral Large 3 675B Instruct?
Claude Mythos Preview has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Claude Mythos Preview or Mistral Large 3 675B Instruct?
Claude Mythos Preview has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Claude Mythos Preview and Mistral Large 3 675B Instruct?
Claude Mythos Preview is available on Anthropic and Microsoft Foundry. Mistral Large 3 675B Instruct is available on AWS Bedrock, NVIDIA NIM, Mistral AI Studio, and Microsoft Foundry. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-16. Data sourced from public model cards and provider documentation.