GPT-5.1 Apply Patch Tool: Automated Code Editing in AG2
AG2 now supports the apply_patch tool (from GPT-5.1 onward) through OpenAI's Responses API, enabling agents to create, update, and delete files using structured diffs. This integration brings precise, controlled file operations directly into your agent workflows.
This article explores how to use apply_patch in AG2, with practical examples for automated code editing, project scaffolding, and multi-file refactoring.
What is Apply Patch?
The apply_patch tool is a built-in capability in GPT-5.1 and above models that enables agents to perform structured file operations using unified diff format. Unlike traditional code generation approaches where agents output raw code blocks that you must manually integrate, apply_patch provides a standardized interface for file modifications that can be directly applied to your codebase.
The tool handles three core operations: - create_file: Generate new files with specified content - update_file: Modify existing files using unified diff format - delete_file: Remove files from the workspace