Missing Mods Checker

What it does at startup Missing Mods Checker runs during the pre-loading phase for Fabric, Forge, and Neoforge. Before the game finishes loading, it scans the mods folder against a list you define in a config file. If any entries are absent, a Java Swing window appears listing each missing mod with a download button that opens the URL you provided. There's also a button that opens the mods folder directly so the player can drop files in manually. The window blocks further loading until the player closes it, so the pack never starts in a broken state. ## Who this is for Pack developers who want to guarantee that certain mods are present. It stops players from accidentally deleting a core mod, prevents unintended updates by pinning exact filenames or regex patterns, and lets you surface optional content - such as platform-exclusive mods - with a one-click download prompt on first launch. ## Configuration You edit missing_mods_checker.json in the pack's config folder. Each entry can target a specific filename or a regex pattern, giving you control over version enforcement. The mod doesn't provide an in-game config screen; changes are made by editing the file directly. ## Compatibility and side requirements The mod requires the client and doesn't support the server side. It works with Fabric, Forge, and Neoforge loaders. Supported Minecraft versions are 1.20, 1.20.1, and 1.21.1 - only these three discrete versions are declared. No other loaders or versions are supported.