Z AI
Released April 7, 2026

GLM 5.1

GLM 5.1 by Z AI is a flagship agentic engineering model, a MoE built for long-horizon coding and tool use with sustained optimization across long runs.

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Model Overview

Capabilities, design details, and architectural traits

GLM 5.1 - Flagship Agentic Engineering Model

GLM-5.1 is Z.ai's next-generation flagship model for agentic engineering: an update to GLM-5 built specifically to stay effective on long-horizon coding and tool-use tasks where earlier models, including GLM-5 itself, tend to plateau.

Defining Characteristics

  • Sustained Long-Horizon Optimization: revisits its own reasoning and revises strategy through repeated iteration, sustaining optimization over hundreds of rounds and thousands of tool calls - performance keeps improving the longer it runs.
  • DeepSeek Sparse Attention MoE: built on the GLM-5 architecture, which integrates DeepSeek Sparse Attention (DSA).

Why It Exists

Built to fix a specific failure mode in prior models, including GLM-5: exhausting familiar techniques early and plateauing on agentic tasks, regardless of how much time or compute they're given.

Benchmark Performance

Independent evaluations · Artificial Analysis

26.1%
Intelligence
55.8%
Coding Index
23.9%
Agentic Index

Accuracy & Capability Details

GPQA - Graduate Science86.8%
Humanity's Last Exam30.1%
SciCode - Scientific Coding44.8%
Instruction Following76.3%
Long Context Reasoning73.7%
τ²-Bench - Agentic Tasks97.7%
TerminalBench - System Control43.2%

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Model Details
General Info
ProviderZ AIAnthropicAnthropic
Release DateApril 7, 2026September 22, 2026September 28, 2026
Knowledge Cutoff--Jun 2026
Context & Limits
Context Window203K
1M
Best Context Window
1M
Best Context Window
Pricing (per 1M tokens)
Input Pricing
$1.38
Best Input Pricing
$4$2
Output Pricing
$4.40
Best Output Pricing
$20$10
Modalities
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Benchmarks (0-100)
Intelligence Index24.2
57.6
Best Intelligence Index
56.0
Coding Index---
Agentic Index---
GLM 5.1
Claude Opus 5.5
Claude Sonnet 5.5

Humanity's Last Exam

Extremely difficult logical reasoning and knowledge.

28%
GLM 5.1
Humanity's Last Exam
Score: 28%
GLM 5.1
61%
Claude Opus 5.5
Humanity's Last Exam
Score: 61%
Claude Opus 5.5
55%
Claude Sonnet 5.5
Humanity's Last Exam
Score: 55%
Claude Sonnet 5.5

Long Context Reasoning

Logical reasoning over long context windows.

53%
GLM 5.1
Long Context Reasoning
Score: 53%
GLM 5.1
85%
Claude Opus 5.5
Long Context Reasoning
Score: 85%
Claude Opus 5.5
83%
Claude Sonnet 5.5
Long Context Reasoning
Score: 83%
Claude Sonnet 5.5

SciCode Benchmark

Scientific coding and mathematical modeling.

36%
GLM 5.1
SciCode Benchmark
Score: 36%
GLM 5.1
67%
Claude Opus 5.5
SciCode Benchmark
Score: 67%
Claude Opus 5.5
61%
Claude Sonnet 5.5
SciCode Benchmark
Score: 61%
Claude Sonnet 5.5

Independent evaluation data provided by Artificial Analysis. To view the latest benchmarks and full details, visit their official site.

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