GLM 5.1

• Type: Generation
• Capabilities: reasoning

Overview

Meet GLM-5.1-FP8 - Z.ai's next-generation flagship model for agentic engineering, with significantly stronger coding capabilities than GLM-5. It achieves state-of-the-art performance on SWE-Bench Pro and leads GLM-5 by a wide margin on NL2Repo and Terminal-Bench 2.0, making it especially strong for real-world coding, repository generation, terminal tasks, and long-horizon agentic workflows. GLM-5.1 is designed to stay productive over extended sessions, breaking down ambiguous problems, running experiments, reading results, identifying blockers, and improving through repeated iteration.

Best for:

• Agentic engineering and complex coding tasks
• Long-running tool-use workflows
• Repository generation and terminal-based development
• Ambiguous problems requiring judgment, experimentation, and sustained reasoning

Max Total Tokens: 202752

Sampling Parameters:

We have set the default sampling parameters using the recommended values from the GLM-5.1 generation configuration:

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Temperature=1.0 and TopP=0.95.

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You can adjust these on a per-request basis by setting the sampling parameters in the request body.

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Thinking Mode:

This model reasons step-by-step before responding by default.

This model is built for long-horizon agentic work and can sustain useful reasoning over extended sessions involving planning, tool use, experiments, and iterative debugging.

Reasoning efforts

• Supported: none, minimal, low, medium, high, xhigh, max

See the reasoning effort guide for request examples.

Pricing

Priority	Input Tokens (per 1M)	Output Tokens (per 1M)
Realtime1	$1.05	$3.50
Async	$0.79	$2.63
Batch (24h)	$0.53	$1.75

Playground

Open this model in the Playground.

Footnotes

1. Realtime availability is limited. Doubleword is primarily a batch API. ↩