GPT-5.5

GPT-5.5

OpenAI
Leanstral

Leanstral

Mistral AI
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About

GPT-5.5 is an advanced AI model designed to handle complex, real-world tasks with greater autonomy and efficiency. It quickly understands user intent and can execute multi-step workflows such as coding, research, data analysis, and document creation with minimal guidance. Instead of requiring step-by-step instructions, GPT-5.5 plans tasks, uses tools, evaluates outputs, and continues working until completion. It excels in knowledge work, software development, and analytical problem-solving, helping users move from idea to execution faster. The model is built to operate across tools and environments, making it highly effective for modern digital workflows. With strong reasoning and persistence, GPT-5.5 enables individuals and teams to complete demanding work more efficiently and accurately.

About

Leanstral is an open-source code agent developed by Mistral AI specifically designed to work with the Lean 4 proof assistant. The model focuses on generating code while also formally verifying its correctness against strict mathematical or software specifications. Unlike traditional coding assistants, Leanstral integrates directly with formal proof systems to ensure that generated code satisfies defined logical requirements. Its architecture is optimized for proof engineering tasks and operates efficiently with sparse model parameters. Leanstral is released under the Apache 2.0 license, making it freely accessible for developers, researchers, and organizations to use and customize. The model is designed to operate within real-world formal repositories rather than isolated problem environments. By combining code generation with formal verification, Leanstral aims to reduce the need for manual human review in complex software and mathematical development.

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

GPT-5.5 is ideal for enterprises, developers, researchers, and business teams looking to automate complex workflows, enhance productivity, and scale operations using AI and workspace agents

Audience

AI researchers, software engineers, and developers working with formal verification, proof assistants, and mathematically rigorous software development

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

$5 per 1M tokens (input)
$5 per 1M input tokens and $30 per 1M output tokens, with a 1M context window
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
design 5.0 / 5
support 5.0 / 5

Reviews/Ratings

Overall 0.0 / 5
ease 0.0 / 5
features 0.0 / 5
design 0.0 / 5
support 0.0 / 5

This software hasn't been reviewed yet. Be the first to provide a review:

Review this Software

Pros & Cons from Real Users

Pros

  • GPT-5.5 has been outstanding for AI agents and coding work. It feels smarter, more persistent, and better at handling complex technical tasks than previous models. I use it for debugging, writing code, planning agent workflows, and working through multi-step software problems. It is especially strong when I need clear reasoning, structured output, and practical code that I can actually use.

Cons

  • GPT-5.5 still works best with clear instructions and enough project context. For large codebases or production-level changes, I still review the code carefully before shipping it.

Training

Documentation
Webinars
Live Online
In Person

Training

Documentation
Webinars
Live Online
In Person

Company Information

OpenAI
Founded: 2015
United States
openai.com

Company Information

Mistral AI
Founded: 2023
France
mistral.ai

Alternatives

Claude Fable 5

Claude Fable 5

Anthropic

Alternatives

Claude Mythos 5

Claude Mythos 5

Anthropic
Claude Opus 4.6

Claude Opus 4.6

Anthropic
Claude Mythos

Claude Mythos

Anthropic
GPT-5.5 Pro

GPT-5.5 Pro

OpenAI
Leanstral 1.5

Leanstral 1.5

Mistral AI

Categories

Categories

Integrations

AWS GovCloud
AnyAPI
ChatGPT Agent
ChatGPT Pro
Claw Code
Factory Droid
GPT-5.1-Codex-Max
GPT-5.4 mini
GPT‑5.4‑Cyber
LaunchLemonade
Mistral AI Studio
Node.js
OpenAI Codex
OpenRouter
Oz
PrivatClaw
Simtheory
Transor
TypeScript
Visual Studio Code

Integrations

AWS GovCloud
AnyAPI
ChatGPT Agent
ChatGPT Pro
Claw Code
Factory Droid
GPT-5.1-Codex-Max
GPT-5.4 mini
GPT‑5.4‑Cyber
LaunchLemonade
Mistral AI Studio
Node.js
OpenAI Codex
OpenRouter
Oz
PrivatClaw
Simtheory
Transor
TypeScript
Visual Studio Code
Claim GPT-5.5 and update features and information
Claim GPT-5.5 and update features and information
Claim Leanstral and update features and information
Claim Leanstral and update features and information