Xcode 27 and Agent Client Protocol (ACP) Integration

Native Device Automation and ACP

Xcode 27 introduces Device Hub, a centralized interface for managing simulators and physical devices, which now supports native automation for testing workflows. The IDE implements the Agent Client Protocol (ACP), a standardized communication layer between agents and editors that functions similarly to the Language Server Protocol (LSP). This protocol allows developers to integrate various coding agents—including Claude, Codex, Gemini, and Cursor Composer—directly into the Xcode environment without relying on third-party workarounds.

Agent Integration and Tooling

Users can add custom agents by configuring them via the ACP argument in the Xcode agent settings. Once connected, these agents gain access to native Xcode tools, such as simulator interaction, screenshot capture, and test validation. Xcode 27 automatically detects and exposes MCP (Model Context Protocol) servers defined in the project-level mcp.json file, making them available alongside the built-in Xcode tools. While the built-in tools offer higher precision for UI interactions like swipes and taps compared to external MCP implementations, the current beta lacks a toggle to selectively enable or disable specific MCP servers, leading to potential redundancy when both native and third-party tools are present.

Model Performance and Limitations

Testing with GLM 5.2 revealed that the model lacks vision input capabilities, which significantly hinders its ability to perform visual validation loops—a core requirement for automated testing in Xcode. While agents like Claude can successfully utilize native tools to inspect context files and execute tests, the effectiveness of the workflow remains heavily dependent on the specific agent's ability to process visual feedback from the simulator.