GPT-5.3-Codex Now Available in github.com, GitHub Mobile, and Visual Studio

GPT-5.3-Codex Expands Across Copilot Surfaces

GitHub has expanded the availability of GPT-5.3-Codex within Copilot to cover github.com, GitHub Mobile, and Visual Studio, adding to the VS Code access that was established at the model's general availability announcement earlier in February 2026. This expansion means that GPT-5.3-Codex is now accessible across all major Copilot surfaces.

GPT-5.3-Codex delivers approximately 25% faster performance on agentic coding tasks compared to its predecessor, making it particularly well-suited for the multistep workflows that Copilot's agentic features rely on. The performance improvement is most noticeable in complex tasks that require multiple rounds of code generation, testing, and iteration.

Platform-Specific Availability

github.com

On github.com, GPT-5.3-Codex is available in the Copilot Chat panel, pull request reviews, and issue discussions. Developers can select GPT-5.3-Codex from the model picker when starting a new Copilot interaction. The model is available for both chat-based interactions and agentic workflows that operate on pull requests and issues.

GitHub Mobile

GitHub Mobile now supports GPT-5.3-Codex in its Copilot Chat interface, bringing the faster model to on-the-go code review and discussion. Mobile users can select the model from the same model picker interface available on other platforms.

Visual Studio

Visual Studio users can now access GPT-5.3-Codex through the Copilot Chat panel and inline suggestions. The model is available in Visual Studio 2022 version 17.14 and later, with support for both C# and C++ development workflows where the model's improved performance on complex codebases is most beneficial.

Model Characteristics

GPT-5.3-Codex is optimized specifically for code-related tasks, with particular strengths in understanding large codebases, generating contextually appropriate code, and executing multistep agentic workflows. The model maintains the same context window and capability profile as in its VS Code release, ensuring consistent behavior across all Copilot surfaces.

Availability

GPT-5.3-Codex is available immediately across github.com, GitHub Mobile, and Visual Studio for all Copilot subscribers. Usage counts against premium model usage limits for Pro, Business, and Enterprise plans. Pro+ subscribers have unlimited access to the model across all surfaces.