diff --git a/AGENTS.md b/AGENTS.md
index 23c244e..aeda7b6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -8,7 +8,7 @@
 
 - `Example.slnx` — XML-based solution referencing the `src/` and `tests/` projects.
 - `src/Example/` — the library project (`Example.csproj`) with `ExampleClass.cs` and `FeatureFlags.cs` (the OpenFeature feature-flag scaffold; see *Feature flags*).
-- `tests/Example.Tests/` — xUnit test project (`Example.Tests.csproj`, `ExampleClassTests.cs`) using `Microsoft.NET.Test.Sdk`, `coverlet.collector`, and `xunit.runner.visualstudio`.
+- `tests/Example.Tests/` — xUnit v3 test project (`Example.Tests.csproj`, `ExampleClassTests.cs`). It runs on Microsoft.Testing.Platform: xUnit v3 4.x needs that runner on the .NET 10 SDK, and `global.json` opts in with `"test": { "runner": "Microsoft.Testing.Platform" }`. It references `Microsoft.Testing.Extensions.CodeCoverage`, so the shared `run-dotnet-tests` workflow collects Cobertura coverage.
 - `AGENTS.md` — the canonical, cross-tool project instructions.
 - `CLAUDE.md` / `GEMINI.md` — exact one-line `@AGENTS.md` shims; never copy guidance into them.
 - `.editorconfig` — formatting and analyzer rules enforced at build.
diff --git a/global.json b/global.json
index 34cc7a1..a9f688f 100644
--- a/global.json
+++ b/global.json
@@ -2,5 +2,8 @@
   "sdk": {
     "version": "10.0.300",
     "rollForward": "latestFeature"
+  },
+  "test": {
+    "runner": "Microsoft.Testing.Platform"
   }
 }
diff --git a/tests/Example.Tests/Example.Tests.csproj b/tests/Example.Tests/Example.Tests.csproj
index f4ee4a9..0e6107c 100644
--- a/tests/Example.Tests/Example.Tests.csproj
+++ b/tests/Example.Tests/Example.Tests.csproj
@@ -17,6 +17,7 @@
   <ItemGroup>
     <PackageReference Include="coverlet.collector" Version="10.0.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.9.0" />
+    <PackageReference Include="Microsoft.Testing.Extensions.CodeCoverage" Version="18.11.2" />
     <PackageReference Include="xunit.v3" Version="4.0.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="4.0.0" />
   </ItemGroup>