How to Play Black Mesa Co-op on a Dedicated Server (SourceCoop)

Black Mesa has no built in campaign co-op, but the community plugin SourceCoop adds it to a dedicated server. You install Metamod:Source, then SourceMod 1.12 build 7163 exactly (the SourceCoop team warns that newer builds break it), then extract the latest SourceCoop release into the server's bms folder, set mp_teamplay 1 in server.cfg and start the server on bm_c0a0a. Everyone needs their own copy of Black Mesa, and you need a dedicated server: the plugins do not run on a listen server started from the game menu.

What SourceCoop is, honestly

SourceCoop is an open source SourceMod plugin on GitHub that lets single player Source campaigns be played together. It supports Black Mesa and Half-Life 2: Deathmatch. It handles checkpoints, respawns, carrying your health, armor and weapons between maps, intro skipping votes, a revive system and difficulty that scales with player count.

Set your expectations before you start:

• It is a mod on top of a single player game. Scripted scenes, NPC behavior and some puzzles were built for one player. The SourceCoop team patches maps with per map config files (called EDT files), and most of the campaign plays well, but you will meet odd moments.
• Black Mesa updates can break it. In May 2025 the "Resonance Decade" update needed two hotfix releases (v1.5 beta 1 and beta 2) before servers worked again. The current release at the time of writing is v1.6, the Winter Patch, from December 2025.
• SourceMod is pinned. Every recent release says to install SourceMod 1.12 build 7163 and "DO NOT INSTALL NEWER VERSIONS", because later builds have a regression in their detour hooking.

What you need

Use packages that match the server's operating system. A Linux server needs the linux.tar.gz builds even if you are uploading from a Windows PC. If you still need the server itself, start with how to host a Black Mesa server.

Step 1: Back up and stop the server

Stop the server and copy the bms/cfg folder somewhere safe. If you already run SourceMod for deathmatch, back up bms/addons too, because the pinned SourceMod build may be older than what you have.

Step 2: Install Metamod:Source

Download the 1.12 stable package from metamodsource.net. Extract it and copy its addons folder into bms, so these exist:

bms/addons/metamod/
bms/addons/metamod.vdf

Start the server and type meta version. A version line means Metamod is loaded. "Unknown command" means metamod.vdf is in the wrong place.

Step 3: Install SourceMod build 7163

Do not grab the newest build from the download page. Get the pinned one from SourceMod's build archive. For Linux it is:

https://sm.alliedmods.net/smdrop/1.12/sourcemod-1.12.0-git7163-linux.tar.gz

For Windows, use the sourcemod-1.12.0-git7163-windows.zip file from the same folder. Extract it and copy both addons and cfg into bms, merging with what is there. Restart and check:

sm version
meta list

sm version should report build 7163.

Step 4: Install SourceCoop

Download the latest -bms.zip from the SourceCoop releases page and extract it directly into bms. The archive is laid out to merge into that folder, adding the plugin files under addons/sourcemod/ plus the map configs it needs. Do not unzip it into a subfolder named after the zip.

On Linux over SSH:

cd "Black Mesa Dedicated Server/bms"
unzip -o ~/SourceCoop-1.6-bms.zip

If you would rather not do this by hand on your own PC, SourceCoop also offers install scripts (srccoop-bms-linux-install.sh and srccoop-bms-windows-install.ps1) and the SCLauncher tool, which download the server, the pinned SourceMod and the plugin in one go.

Step 5: Set server.cfg for co-op

Replace your deathmatch settings in bms/cfg/server.cfg with co-op friendly ones. These come from SourceCoop's own install script:

hostname "Black Mesa Co-op"
sv_password ""           // set one for a friends only run
mp_teamplay 1            // puts everyone on the scientist team
mp_friendlyfire 0
mp_forcerespawn 1
mp_fraglimit 0           // stops the map ending on score
mp_timelimit 0

A few SourceCoop settings worth knowing, which you can add to the same file:

Step 6: Start on the first chapter

Start the server on the tram ride map:

./srcds_run -console -game bms -ip 0.0.0.0 +maxplayers 8 +mp_teamplay 1 +map bm_c0a0a

Campaign maps follow the bm_c naming (bm_c0a0a, bm_c1a0a, bm_c1a1a and so on), and SourceCoop changes level when players reach the end of each map. To check the plugin is live, type sm plugins list in the server console and look for the SourceCoop entries, or type !coopmenu in chat (sm_coopmenu in the console) once connected.

Commands players will use

Admin commands need you in bms/addons/sourcemod/configs/admins_simple.ini, for example "STEAM_0:1:12345678" "99:z", then sm_reloadadmins.

Custom campaigns from the Workshop

SourceCoop keeps a Steam Workshop collection of custom maps that ship with co-op configs. Two rules apply. Every player must subscribe to the map on the Workshop before launching the game, because Black Mesa does not download Workshop maps from the server; anyone missing it sees "Missing map! Subscribe to SourceCoop workshop collection + restart game". And the server needs the map files copied in by hand, since the dedicated server does not subscribe to anything. The SourceCoop wiki recommends copying the Workshop item's files into bms/custom on the server and keeping them updated yourself.

When an update breaks it

If the server crashes or players fall through the world right after a Black Mesa patch, check the SourceCoop releases page and Discord for a hotfix before changing anything else. Do not "fix" it by updating SourceMod past 7163. Restore your backup if you need the server back for tonight (see how to back up a game server if you have not set that up). If players simply cannot reach the server after an update, that is usually a version mismatch, covered in Black Mesa server not showing or cannot connect. On a host that updates the game automatically on start, you can turn auto updating off to keep a working combination, but players who already have the new client will not be able to join an old server, so that only buys a little time.

Co-op without the setup

On a Black Mesa server from GamezServers you upload Metamod, SourceMod 7163 and SourceCoop into bms with the file manager or SFTP, set Default Map to bm_c0a0a and Max Players to your group size in the panel, and edit server.cfg in the browser. The server runs the Linux build, so use the Linux packages. Take a one click backup before any update, and the Auto Update setting lets you choose when the game patches. A co-op campaign is comfortable on the 4 GB plan.

FAQ

Does Black Mesa have official co-op?

No. The base game's multiplayer is deathmatch and team deathmatch only. Campaign co-op comes from the community SourceCoop plugin on a dedicated server.

Why does SourceCoop need SourceMod build 7163?

The SourceCoop developers found a regression in the detour hooking of newer SourceMod builds, so they pin 1.12 build 7163 and tell server owners not to install newer versions until they say otherwise.

Can I run SourceCoop on a listen server from the game?

No. SourceMod plugins need a dedicated server, which is the free Black Mesa Dedicated Server (app 346680). It can run on the same PC you play on.

How many players work best in Black Mesa co-op?

Small groups of 2 to 8 work best. The difficulty scales up per player by default, and big groups make the scripted scenes chaotic.

Do my friends need to install anything?

Only Black Mesa itself. The plugin runs on the server. For custom Workshop campaigns, they also subscribe to those maps before launching the game.