GLM-5.3

GLM-5.3

Z.ai
+
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About

Claude Fable 5.1 is Anthropic’s advanced AI model for coding, knowledge work, research, and long-running agentic tasks. It is designed to improve on Claude Fable 5 with stronger performance across software engineering, scientific research, multidisciplinary reasoning, computer use, business workflows, and complex problem solving. The model can handle extended multi-step work, verify its own results, diagnose difficult software issues, and operate effectively across tool-heavy workflows. Anthropic also reduced cache-read pricing for Fable 5.1, lowering typical usage costs compared with Fable 5 and creating larger savings for highly agentic workloads. Fable 5.1 includes updated safeguards intended to reduce false positives while allowing more legitimate cybersecurity tasks such as vulnerability discovery for defensive purposes. The model is available through Claude products, the Claude API, Amazon Web Services, Google Cloud, and Microsoft Azure.

About

GLM-5.3 is Z.ai’s frontier coding model designed for complex software engineering, long-horizon agent tasks, and advanced post-training research. The model uses the same base model as GLM-5.2, with improvements coming from scaled post-training across more environments, more diverse tasks, and larger compute investment. GLM-5.3 delivers stronger coding performance, better task ownership, improved benchmark results, and greater efficiency across realistic development workflows. It is built to handle complex coding tasks, production-style engineering work, research environments, automation tasks, and agentic workflows that require multi-step execution. The model also shows emergent cyber capabilities in vulnerability discovery and exploitation-chain reasoning, with safety evaluation and hardening planned before open-weight release.

Platforms Supported

Windows
Mac
Linux
Cloud
On-Premises
iPhone
iPad
Android
Chromebook

Platforms Supported

Windows
Mac
Linux
Cloud
On-Premises
iPhone
iPad
Android
Chromebook

Audience

Software developers, researchers, enterprises, analysts, knowledge workers, and AI application teams that need advanced coding, reasoning, research, and long-running agentic capabilities

Audience

Software engineers, coding agent builders, AI researchers, ML infrastructure teams, security researchers, developer tool teams, automation teams, technical leaders, and organizations that need frontier coding models, long-horizon reasoning, production-style software engineering, benchmark-driven model evaluation, reinforcement learning research, coding-agent integrations, reasoning effort controls, ZCode workflows, and advanced technical task automation

Support

Phone Support
24/7 Live Support
Online

Support

Phone Support
24/7 Live Support
Online

API

Offers API

API

Offers API

Screenshots and Videos

Screenshots and Videos

Pricing

$10 per 1M tokens (input)
$10 per million input tokens and $50 per million output tokens
Free Version
Free Trial

Pricing

Free
Open source
Free Version
Free Trial

Reviews/Ratings

Overall 5.0 / 5
ease 5.0 / 5
features 5.0 / 5

Reviews/Ratings

Overall 5.0 / 5
ease 5.0 / 5
features 5.0 / 5

Pros & Cons from Real Users

Pros

  • This feels like the model you reach for when the work is genuinely difficult. Not every task needs Fable, but for complex coding, long-horizon agents, deep research, and big messy knowledge-work projects, Fable 5.1 looks built for the hard stuff. The 1M-token context window is a huge advantage. For developers and AI power users, that means you can work across large repos, long docs, research sets, transcripts, spreadsheets, and project history without constantly chopping everything into pieces. I also like that Anthropic specifically calls out document, spreadsheet, and slide work. That makes it feel useful beyond coding alone — more like a high-end model for serious professional workflows.

Cons

  • The downside is price and complexity. Anthropic says most workloads should start with Claude Opus 5, and Fable 5.1 is better reserved for demanding reasoning or cases where Opus 5 still falls short.

Pros & Cons from Real Users

Pros

  • The thing I like most is that GLM-5.3 feels aimed at serious engineering work, not casual prompting. It is built around coding agents, long-running software tasks, debugging, and the kind of multi-step execution that actually matters when you are working inside real repos. The post-training jump is also interesting. Z.ai is not just talking about a bigger model; it is pushing the idea that better training on agentic coding and cyber workflows can make the model more useful in practice.

Cons

  • The cybersecurity angle is impressive, but it is also where I would be most cautious. Strong vulnerability discovery and cyber reasoning can be useful for defense, audits, and secure engineering, but I would want very clear controls around how it is used.

Training

Documentation
Webinars
Live Online
In Person

Training

Documentation
Webinars
Live Online
In Person

Company Information

Anthropic
Founded: 2021
United States
claude.ai

Company Information

Z.ai
Founded: 2023
China
z.ai/

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Grok 4.6

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GPT-5.6 Sol

GPT-5.6 Sol

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Claude Opus 5

Claude Opus 5

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Grok 4.6

Grok 4.6

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GLM-5

GLM-5

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Claude Fable 5

Claude Fable 5

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GLM-5.1

GLM-5.1

Z.ai

Categories

Categories

Integrations

Amp
C
C#
C++
CSS
Cherry Studio
Claude Code
Claw Code
Go
HTML
Hermes Agent
Java
OpenClaw
Python
R
Rust
Shiori
Swift
Vercel AI Gateway
Zo Computer

Integrations

Amp
C
C#
C++
CSS
Cherry Studio
Claude Code
Claw Code
Go
HTML
Hermes Agent
Java
OpenClaw
Python
R
Rust
Shiori
Swift
Vercel AI Gateway
Zo Computer
Claim Claude Fable 5.1 and update features and information
Claim Claude Fable 5.1 and update features and information
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