Composer 1.5vsGLM-5.1
Composer 1.5 | GLM-5.1 | |
|---|---|---|
| Specifications | ||
Parameters | — | 744B |
Context window | — | 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. | — | 22% |
Next.js coding Next.js EvalsVercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | 67% | 75%Best |
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% |
Multidisciplinary reasoning Humanity's Last Exam · with toolsHumanity's Last Exam — extremely hard expert questions across many subjects. “With tools” means the AI is allowed to search the web or run code while answering. Higher is better. | — | 52.3% |
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% |
Community preference Arena Elo (Text)Real people chat with two anonymous AIs side by side and vote for the answer they prefer. Votes become a chess-style Elo rating on arena.ai — it measures which AI people actually like, not test scores. Higher is better. | — | 1468 |
Community preference (code) Arena Elo (Code)Like the text arena, but people vote on which AI writes better code. The votes become a chess-style Elo rating on arena.ai. Higher is better. | — | 1510 |
| Overview | ||
| Company | SpaceXAI | Z.ai |
| Release date | Feb 9 2026 | Apr 7 2026 |
| Access | Proprietary | Open Weight |
Which is better: Composer 1.5 or GLM-5.1?
GLM-5.1 leads Composer 1.5 on 1 of the 1 benchmark they both report (Next.js Evals). Composer 1.5 shipped 57 days before GLM-5.1, so benchmark comparisons should account for the intervening progress.
Composer 1.5 is proprietary, while GLM-5.1 is open weight.
On Next.js Evals, GLM-5.1 leads at 75% vs Composer 1.5 at 67%.
Frequently asked questions
Composer 1.5 was released by SpaceXAI on Feb 9 2026.
GLM-5.1 was released by Z.ai on Apr 7 2026.
GLM-5.1 leads on Next.js Evals — Composer 1.5 67% vs GLM-5.1 75%.
Composer 1.5 is a proprietary model released by SpaceXAI. GLM-5.1 is an open weight model released by Z.ai.
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