Claude Fable 5 vs GLM-5.3: Specs & Benchmark Comparison
Claude Fable 5 is developed by Anthropic, while GLM-5.3 comes from Zhipu AI. Claude Fable 5 was released in June 2026, and GLM-5.3 followed 2 months later in August 2026. GLM-5.3 has a published size of about 753 billion parameters; Anthropic has not disclosed the parameter count of Claude Fable 5.
The two models share 7 published benchmarks. Claude Fable 5 leads on 5 of them, GLM-5.3 on 2. The widest gaps are on AutomationBench, where GLM-5.3 scores 48.2% against 17.4%; ExploitBench, where Claude Fable 5 scores 78.0% against 54.4%. Averaged across everything we track, Claude Fable 5 sits at 59.8% and GLM-5.3 at 52.2%.
GLM-5.3 is the cheaper API at $1.40 per million input tokens and $4.40 per million output tokens, roughly 7 times cheaper than Claude Fable 5 at $10 and $50. Both accept a context window of about 1M tokens. Claude Fable 5 accepts text and images as input, while GLM-5.3 accepts text.
| Characteristic | Claude Fable 5 | GLM-5.3 |
|---|---|---|
| Company | Anthropic | Zhipu AI |
| Release Date | June 9, 2026 | August 14, 2026 |
| Parameters | — | 753B |
| Multimodal | Yes | No |
| Context (input) | 1.0M | 1.0M |
| Context (output) | 128K | 131K |
| Input Price / 1M | $10.00 | $1.40 |
| Output Price / 1M | $50.00 | $4.40 |
| Average Score | 59.8% | 52.2% |
| Benchmarks | ||
| AutomationBench | 17.4% | 48.2% |
| ExploitBench | 78.0% | 54.4% |
| FrontierSWE | 90.0% | 78.0% |
| Terminal-Bench 2.1 | 84.3% | 88.0% |
| DeepSWE 1.1 | 70.0% | 66.9% |
| Terminal-Bench 4.0 | 44.5% | 41.8% |
| Humanity's Last Exam | 64.5% | 62.5% |
Visual Benchmark Comparison
Verdict
GLM-5.3 leads in 3 out of 4 comparison categories.
Both models show comparable average scores: Claude Fable 5 — 0.6, GLM-5.3 — 0.5.
GLM-5.3 is 10.3x cheaper: input $1.40/1M vs $10.00/1M tokens.
GLM-5.3 supports a larger context: 1M vs 1M tokens.
GLM-5.3 is newer: released 8/14/2026 vs 6/9/2026.
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Frequently Asked Questions
Which is better for coding — Claude Fable 5 or GLM-5.3?
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Which has a larger context window — Claude Fable 5 or GLM-5.3?
The Claude Fable 5 and GLM-5.3 comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the Claude Fable 5 or GLM-5.3 page. See also the complete list of AI model comparisons.