In short
How they differ.
Worked out from the figures below. Prices and specs are the makers' own, read Oct 20, 2026.
- GLM-5.3 can be downloaded and run on your own machine; Claude Mythos 5.1 can't.
- No independent board we follow ranks both models yet.
Side by side
The specs.
| Claude Mythos 5.1 | GLM-5.3 | |
|---|---|---|
| Made by | Anthropic · US | Z.ai (Zhipu AI) · China |
| Released | Sep 1, 2026 | Not stated |
| Price per 1M tokens | No public price | $1.40 in / $4.40 out |
| Context window | Not stated | 1M |
| Takes in | Not stated | text |
| Download and run it yourself | No | Yes (glm-5.3 (license tag shown on Hugging Face)) |
| Size | Not published | 753B (Hugging Face safetensors size field) parameters |
| Maker says | “Our most capable model for cybersecurity and biology research.” | “GLM-5.3 is Z.ai's latest flagship model, delivering comprehensive advancements in complex software engineering” |
| Sources | Prices, Oct 20, 2026 · Description | Prices, Oct 20, 2026 · Description |
Independent tests
Where they place.
Position on each board we follow (1 is best). Epoch AI's and Vectara's scores are shown; the other boards are linked for their own figures.
More comparisons