/unity-build-pipeline

name: unity-build-pipeline
description: >
  Build and ship Unity 6.3 LTS players: build settings and scenes, player/quality settings, the
  IL2CPP vs Mono scripting backend, managed code stripping, scripted BuildPipeline.BuildPlayer,
  and CI/headless builds. Use when configuring or automating a build, choosing a scripting
  backend, shrinking build size, or when the user mentions Unity build, player settings,
  IL2CPP, code stripping, or Addressables.

Unity Build Pipeline

Configure, script, and automate Unity 6.3 LTS player builds: scenes, platform target, scripting backend, stripping, and headless/CI builds. Targets **Unity 6.3 LTS (6000.3)**.

When to use

• Use when setting up Build Settings/Profiles, choosing a platform and scripting backend

(Mono vs IL2CPP), reducing build size with managed stripping, scripting a repeatable build with `BuildPipeline.BuildPlayer`, or wiring a CI/headless build.

• Use when the project has `ProjectSettings/EditorBuildSettings.asset` or a CI build script.

**When *not* to use:** authoring a CI service config end-to-end is DevOps; this skill covers the Unity-side build API and settings. Console/platform certification specifics are platform-NDA territory. Storefront submission → `steam-publish` / `itch-publish`.

Core workflow

1. **List the scenes to build** (File → Build Profiles/Settings → Scene List, or `EditorBuildSettings.scenes`). Only listed, enabled scenes ship; scene 0 is the start scene. 2. **Pick the platform target** and switch the active build target if needed (`BuildTarget` / `EditorUserBuildSettings`). 3. **Choose the scripting backend** (Player Settings): **Mono** (fast iteration, desktop) vs **IL2CPP** (AOT C++; required for many platforms, better perf, harder to reverse). IL2CPP needs the platform's C++ toolchain installed. 4. **Tune size/perf:** set Managed Stripping Level (Disabled → Minimal → Low → Medium → High) and protect reflection-only code with a `link.xml`. Set Quality Settings per platform. 5. **Script the build** with `BuildPipeline.BuildPlayer(BuildPlayerOptions)` and **inspect the returned `BuildReport`** — a non-`Succeeded` result must fail your pipeline. 6. **Run headless** for CI with `-batchmode -quit -executeMethod`, and check the exit code. 7. **Verify** the actual output runs (launch the player), not just that the build returned without throwing.

Patterns

1. Scripted build with a result check

using UnityEditor;
using UnityEditor.Build.Reporting;
using UnityEngine;

public static class BuildScript
{
    [MenuItem("Build/Windows x64")]
    public static void BuildWindows()
    {
        var options = new BuildPlayerOptions
        {
            scenes = new[] { "Assets/Scenes/Main.unity", "Assets/Scenes/Level1.unity" },
            locationPathName = "Builds/Windows/Game.exe",
            target = BuildTarget.StandaloneWindows64,
            options = BuildOptions.None,            // add BuildOptions.Development for a dev build
        };

        BuildReport report = BuildPipeline.BuildPlayer(options);
        BuildSummary summary = report.summary;

        if (summary.result != BuildResult.Succeeded)
            throw new System.Exception($"Build failed: {summary.totalErrors} errors");
        Debug.Log($"Build OK: {summary.totalSize} bytes in {summary.totalTime}");
    }
}

2. Headless / CI invocation

# Exit code is 0 on success; -quit ensures the editor closes; -nographics for build servers.
Unity -batchmode -quit -nographics \
  -projectPath "/path/to/Project" \
  -executeMethod BuildScript.BuildWindows \
  -logFile -

3. Protect stripped code with `link.xml`

<!-- Assets/link.xml — keep types the linker can't see are used (reflection, JSON, plugins). -->
<linker>
  <assembly fullname="MyGameRuntime" preserve="all"/>
</linker>

Pitfalls

• **A scene loads in the Editor but is missing in the build** — it isn't in the Build Settings

scene list (or is disabled). `SceneManager.LoadScene` only sees listed scenes.

• **IL2CPP build fails on a fresh machine** — the platform C++ toolchain (e.g. Windows build

tools, Android NDK) isn't installed. Mono has no such requirement.

• **`MissingMethodException`/`TypeLoadException` only in the build** — managed stripping removed

reflection-only code. Lower the stripping level or add a `link.xml` preserve entry.

• **Treating "BuildPlayer returned" as success** — always check `BuildReport.summary.result`;

it can return with errors.

• **Addressables content is stale/missing** — Addressables (`com.unity.addressables`) need a

*separate* content build (Build → Addressables) and a profile pointing at the right load path; a player build alone doesn't rebuild them.

• **Shipping a Development build** — `BuildOptions.Development` enables the profiler/debugging

and is slower; use `BuildOptions.None` for release.

References

• For a complete **multi-platform CI build script** (target switching, version stamping,

argument parsing, exit codes) and an Addressables content-build call, read `references/ci-build-script.md`.

• Primary docs: `ScriptReference/BuildPipeline.BuildPlayer`, Unity Manual build sections

(player settings, managed code stripping).

Related skills

• `steam-publish` / `itch-publish` — distributing the player you just built.
• `unity-csharp-scripting` — editor scripting conventions used by build scripts.