Valve adds "all the Team Fortress 2 client and server game code" to its Source mod tools, letting modders "build completely new games based on TF2" and publish them on Steam

Valve has just issued a massive Source SDK update giving modders access to the Team Fortress 2 game code, opening the door for them to build all-new games based on the classic FPS and publish those games on Steam.

"This update will allow content creators to build completely new games based on TF2," Valve explains in its announcement. "We're also doing a big update to all our multiplayer back-catalogue Source engine titles (TF2, DoD:S, HL2:DM, CS:S, and HLDM:S), adding 64-bit binary support, a scalable HUD/UI, prediction fixes, and a lot of other improvements!"

The Source SDK is essentially a set of freely available mod tools from Valve. "Unlike the Steam Workshop or local content mods," Valve explains. "this SDK gives mod makers the ability to change, extend or rewrite TF2, making anything from small tweaks to complete conversions possible." Valve notes that while these mods "must be free," their creators will be able to publish them on Steam.

Up to this point major Team Fortress 2 mods have existed in a bit of a gray area over the years. Many of these mods have made use of leaked or reverse engineered source code, which Valve has apparently not been too happy about - as the devs of a mod called TF2 Classic attested when their project was taken offline for months back in 2021. Now that this source code is available publicly and officially, the creators behind these projects can breathe quite a bit easier.

"We're already preparing for the porting efforts and a potential Steam release now that we've been legally enabled to pursue that," TF2 Classic dev sniffy194 said today in the project's Discord.

The devs behind Pre-Fortress 2, another longstanding mod, are similarly excited. "We will be working hard to port PF2 over to this new SDK to meet the requirements necessary to be featured in a full Steam release," developer Sour Dani says in the PF2 Discord. "This also means all of your favorite TF2 Mods are probably going do the same!"

Alongside the SDK update, there's been a big update to TF2 itself with a host of new features, including support for a borderless windowed display mode and some fancy new visual effects. Perhaps predictably, this update has also broken compatibility with the existing versions of mods like TF2 Classic and Pre-Fortress 2, but with the new SDK now available it's likely only a matter of time before these mods get a bigger, better release.

Valve has historically been quite supportive of mods - after all, games like Counter-Strike and Team Fortress itself began life as community projects - which is why many fans were blindsided by the less friendly stance the company had taken with big TF2 mods in particular. Now that these modders have clean source code to work from, however, it seems like Valve's biggest issue has been addressed, and probably won't be too long before we start to see these projects hitting Steam proper.

After 7 years, the final Team Fortress 2 comic is finally here, wrapping up an 11-year saga with a touching tribute to the late voice actor who played Soldier.