Your first server load check

Check that your mod loads on a real Valheim dedicated server, and that a client without the mod can join it.

What you build

One command that starts a disposable dedicated server with your mod, joins a clean client, and writes a private result you can read. Nothing in your Steam installs or saves changes.

You need

  • A Windows PC with Valheim and the free Valheim Dedicated Server installed through Steam.
  • The Steam client running and signed in on that PC's desktop.
  • The .NET 10 SDK.
  • A BepInEx mod with exactly one project in its folder, MyServerMod here.

Read Before a native run once before your first run.

Steps

  1. Install the tool:

    dotnet tool install Valheim.Testing.NativeSmoke --version 0.1.0 --global

    This installs valheim-test.

  2. Build your mod from its project folder:

    cd MyServerMod
dotnet build -c Release

    The build writes your plugin DLL under bin/Release/<target framework>/.

  3. Check the machine:

    valheim-test env preflight

    It prints what it detected, one line per environment, and a verdict. The last line starts with:

    ELIGIBLE: the inventory has a server and a client environment, and this machine's journal holds no run going or left unrecovered.

    If it starts with REFUSED, fix the reason it names and run it again.

  4. Run the load check from the same folder:

    valheim-test server-load

    With no --mod, the tool picks the one plugin under bin/Debug or bin/Release and prints why. It refuses a DLL older than a source file, so rebuild after every edit. It prints the server and client it chose, PREFLIGHT PASSED, then starts the server and the client.

    The run ends like this; the run folder is shortened to <output>:

    Output: <size> in <output>\evidence
PASS
log scan: 4/4 logs present; failure=0 warning=69 expected=0 required-missing=0; most frequent: boot-1 BepInEx log/headless-server-graphics x14, boot-1 Unity log/headless-server-graphics x14, boot-1 Unity log/missing-script x13
SERVER_JOIN_PASS: 1 selected mod(s), 106.5s. Clean client joined with selected server mods absent. Private evidence (5 MB) in <output>

    Warnings like these are normal and do not fail a run. headless-server-graphics is the dedicated server's own errors about its missing graphics device. missing-script is Unity reporting an asset-bundle script it did not load. A line suggesting valheim-test init server follows.

  5. Read the result. Open evidence/result.json in the folder the SERVER_JOIN_PASS line names. Each step has Passed and a Phase, and these four flags are all true:

    "PreflightPassed": true,
"RuntimeReady": true,
"ScenarioPassed": true,
"CleanupVerified": true

  6. Check that the run left nothing:

    valheim-test env status

    The last line reads N runs ended and left nothing. Nothing was changed., and the command exits 0.

What you have now

  • Proof that your mod's dependencies resolve and its plugins load on a dedicated server.
  • Proof that a client without the mod enters the world.
  • A private evidence folder: result.json, junit.xml, the kept logs and dependencies.lock.json. Keep it private; it holds a server password and machine paths.

A pass says nothing about your mod's gameplay.

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