Claude Mythos Preview vs Llama Guard 4 12B
Claude Mythos Preview (2026) and Llama Guard 4 12B (2025) are frontier reasoning models from Anthropic and AI at Meta. Claude Mythos Preview ships a 1M-token context window, while Llama Guard 4 12B ships a 164K-token context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
Claude Mythos Preview fits 6x more tokens; pick it for long-context work and Llama Guard 4 12B for tighter calls.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-07 | 2025-04-05 |
| Context window | 1M | 164K |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Open Source |
| Knowledge cutoff | 2025-12 | - |
Pricing and availability
| Pricing attribute | Claude Mythos Preview | Llama Guard 4 12B |
|---|---|---|
| Input price | - | $0.18/1M tokens |
| Output price | - | $0.18/1M tokens |
| Providers | - |
Capabilities
| Capability | Claude Mythos Preview | Llama Guard 4 12B |
|---|---|---|
| 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
No shared benchmark rows are currently sourced for this pair.
Deep dive
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.
Pricing coverage is uneven: Claude Mythos Preview has no token price sourced yet and Llama Guard 4 12B has $0.18/1M input tokens. Provider availability is 0 tracked routes versus 3. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Claude Mythos Preview when coding workflow support and larger context windows are central to the workload. Choose Llama Guard 4 12B when provider fit 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. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions.
FAQ
Which has a larger context window, Claude Mythos Preview or Llama Guard 4 12B?
Claude Mythos Preview supports 1M tokens, while Llama Guard 4 12B supports 164K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Claude Mythos Preview or Llama Guard 4 12B open source?
Claude Mythos Preview is listed under Proprietary. Llama Guard 4 12B is listed under Open Source. 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 Llama Guard 4 12B?
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 Llama Guard 4 12B?
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.
Which is better for reasoning mode, Claude Mythos Preview or Llama Guard 4 12B?
Claude Mythos Preview has the clearer documented reasoning mode signal in this comparison. If reasoning mode 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 Llama Guard 4 12B?
Claude Mythos Preview is available on the tracked providers still being sourced. Llama Guard 4 12B is available on NVIDIA NIM, Replicate API, and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.