GLM 5.3 Prime vs Claude Fable 5.1: price, context window and capabilities
GLM 5.3 Prime (z-ai/glm-5.3-prime) is a language model from Z.ai and Claude Fable 5.1 (anthropic/claude-fable-5.1) a multimodal language model from Anthropic; both are on the OceanToken API. GLM 5.3 Prime costs less per token than Claude Fable 5.1: $2.80 against $9.00 per 1M input tokens (69% less) and $8.80 against $45.00 per 1M output tokens (80% less). Claude Fable 5.1 is 10% off its official price on OceanToken, for every account. Both have a 1M-token context window (1,000,000 tokens). Both support tool calling and reasoning; only Claude Fable 5.1 also lists structured outputs, image input and file input.
Side by side
| Spec | GLM 5.3 Prime | Claude Fable 5.1 −10% |
|---|---|---|
| Model | GLM 5.3 Primez- | Claude Fable 5.1anthropic/ |
| Publisher | Z.ai | Anthropic |
| Kind | Text | Text & vision |
| Context window | 1M tokens1,000,000 | 1M tokens1,000,000 |
| Input price | $2.80 / 1M tokens | $9.00 / 1M tokens |
| Output price | $8.80 / 1M tokens | $45.00 / 1M tokens |
| Cached input price | $0.56 / 1M tokens | $0.25 / 1M tokens |
| Cache write price | – | $12.50 / 1M tokens |
| Web search price | – | $0.01 / search |
| Discount (vs official, top tier) | — | −10% |
| Inputs | text | text, images and files |
| Outputs | text | text |
| Tool calling | Yes | Yes |
| Reasoning | Yes | Yes |
| Structured outputs | Not listed | Yes |
About these prices
Which should you choose?
- Choose GLM 5.3 Prime to spend less per token: 69% less for input and 80% less for output than Claude Fable 5.1.
- Context size does not separate them: both hold about 1M tokens.
- Choose Claude Fable 5.1 if you need structured outputs, image input and file input: GLM 5.3 Prime does not list them.
- Not sure? Call both with the same OceanToken API key and compare them on your own prompts; each request is billed per use from one prepaid balance.
Get API Key GLM 5.3 Prime Claude Fable 5.1
Frequently asked questions
Which is cheaper, GLM 5.3 Prime or Claude Fable 5.1?
GLM 5.3 Prime. GLM 5.3 Prime costs less per token than Claude Fable 5.1: $2.80 against $9.00 per 1M input tokens (69% less) and $8.80 against $45.00 per 1M output tokens (80% less). Claude Fable 5.1 is 10% off its official price on OceanToken, for every account. The OceanToken console always shows the current price.
Which has the larger context window, GLM 5.3 Prime or Claude Fable 5.1?
Neither. Both have a 1M-token context window (1,000,000 tokens).
Can I call both GLM 5.3 Prime and Claude Fable 5.1 with one API key?
Yes. Both are on the OceanToken API at https://api.oceantoken.ai/v1: one API key and one prepaid balance call either model. Send the model id z-ai/glm-5.3-prime or anthropic/claude-fable-5.1.
Models and publishers
GLM 5.3 Prime · Claude Fable 5.1 · All Z.ai models · All Anthropic models
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