Claude Fable 5 vs GLM-5.1
Anthropic Claude Fable 5 | Z.ai GLM-5.1 | |
|---|---|---|
| Overview | ||
| Company | Anthropic | Z.ai |
| Release date | Jun 9 2026 | Apr 7 2026 |
| Access | Proprietary | Open Weight |
| Specifications | ||
Parameters | — | 744B |
Context window | 1M | 200k |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 56% | — |
Agentic coding SWE-Bench ProCan the AI fix real bugs in real software? It's handed actual problems from open-source projects and has to write code that genuinely solves them. Higher is better. | 80.3% | — |
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 95.5% | — |
Agentic terminal coding Terminal-Bench 2.1Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? Higher is better. | 88% | — |
Agentic terminal coding Terminal-Bench 2.0Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? (Version 2.0 of the test.) Higher is better. | — | 63.5% |
Web browsing BrowseCompCan the AI browse the web and track down hard-to-find answers? Higher is better. | — | 68% |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | — | 86.2% |
Agentic computer use OSWorld-VerifiedCan the AI actually operate a computer — clicking, typing, and using real apps — to finish tasks on its own? Higher is better. | 85% | — |
Knowledge work GDPval-AAMeasures how well the AI does economically valuable knowledge work, judged against human experts. Shown as a rating (like a chess Elo) — higher is better. | 1932 | — |
| Timeline | ||
| Release gap | GLM-5.1 shipped 63 days before Claude Fable 5 | |
Which is better: Claude Fable 5 or GLM-5.1?
Claude Fable 5 and GLM-5.1 don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GLM-5.1 shipped 63 days before Claude Fable 5, so benchmark comparisons should account for the intervening progress.
Context windows are 1M (Claude Fable 5) vs 200k (GLM-5.1). Claude Fable 5 is proprietary, while GLM-5.1 is open weight.
Direct benchmark comparisons are unavailable — Claude Fable 5 and GLM-5.1 don't publish scores on any of the same benchmarks.
Frequently asked questions
Claude Fable 5 was released by Anthropic on Jun 9 2026.
GLM-5.1 was released by Z.ai on Apr 7 2026.
Claude Fable 5 has a 1M context window; GLM-5.1 has 200k.
Claude Fable 5 is a proprietary model released by Anthropic. GLM-5.1 is an open weight model released by Z.ai.