What problem does it solve? Controlling Apple MainStage programmatically is difficult because it has no public real-time API, and MIDI mappings only have meaning within a specific concert. This Skill provides safe, explicit workflows for opening concerts, sending verified MIDI controls, and preparing backing media without risking a live performance setup. ## Core Features & Use Cases - Native concert and patch opening: Deliver approved .concert or .patch files to a chosen MainStage edition (Creator Studio or standalone) via Executor's app_open_document. - Explicit CoreMIDI control: List MIDI destinations, select exact endpoint pairs, and send verified CC, program change, or pitch bend messages on channels 1-16. - Offline media preparation: Trim, mix, and measure audio into M4A files with media_edit and audio_measure for later assignment in MainStage. - Use Case: Before a live show, open the approved concert file, confirm the MIDI destination for your controller, and send a program change to switch patches, all without editing the live concert bundle. ## Quick Start Ask the agent to open an approved MainStage concert file and send a program change to a verified MIDI destination using the apple-pro-apps Executor tools.