One of the most exciting things about Halo: The Master Chief Collection's imminent arrival on PC, starting with Reach today, is that the modders will be able to get their hands on it. While 343 Industries confirmed mod support earlier in the year, it won't be ready for launch, but in the meantime there's a solution that will allow you to muck around in the campaign and custom modes.
In the Halo subreddit's recent Weekly Discussion (cheers ResetEra), a 343 employee clarified that, while official mod support is still being worked on, this doesn't stop players from being able to enjoy the fruits of the modding community's labour, as there's an official workaround that will let everyone bypass Halo: Reach's anti-cheat tools.
"We’re still working to improve this down the road, but for now you will have an option when you launch to bypass anticheat," 343_farn wrote. "This will allow you to play around with campaign and customs but not allow you to play any match made games. I highly suggest making a copy/backup of anything you modify so you’ll be able to switch back and forth easily."
Mods will never be allowed in matchmaking, however, and if you want to play any matchmaking games after bypassing the anti-cheat, you'll need to revert back to the original files.
Modders have already been hard at work, and have been since Halo: Reach's first PC test, and you'll be able to check out what they've been putting together when it launches later today. Here's when Halo: Reach unlocks in your time zone.