diff --git a/TESTING_GUIDE.md b/TESTING_GUIDE.md
index 331af8b729..e98185863c 100644
--- a/TESTING_GUIDE.md
+++ b/TESTING_GUIDE.md
@@ -43,7 +43,7 @@ The test project mirrors the production areas closely.
 - `SymbolExtractorTests.Extract_CSharp_InstallScriptFixture_CompletesWithinPracticalBudget`
   is a coarse runaway guard for the real `InstallScriptTests.cs` C# extraction fixture. Its wall-clock budget is intentionally broader than a benchmark so slower or noisy CI hosts do not fail the suite for ordinary variance.
 - `IndexCommandRunnerTests.RunBackfillFold_PublishedTrimmedBinary_SerializesSuccessAndErrorJson`
-  publishes a trimmed RID-specific CLI and runs whichever entry point the SDK emits (`cdidx.dll` through `dotnet` or the native `cdidx`/`cdidx.exe` apphost). It is reported as skipped on macOS arm64 while the current SDK/ILLink path can crash before exercising `cdidx`. Do not assume every SDK/runtime pair writes a `cdidx.dll` into self-contained publish output.
+  publishes a trimmed RID-specific CLI and runs whichever entry point the SDK emits (`cdidx.dll` through `dotnet` or the native `cdidx`/`cdidx.exe` apphost). It is reported as skipped on macOS arm64 while SDK/ILLink can crash before exercising `cdidx` (#2586). Do not assume every SDK/runtime pair writes a `cdidx.dll` into self-contained publish output.
 - `McpServerTests.cs`
   MCP JSON-RPC behavior and tool outputs.
 - `HttpMcpTransportTests.cs`
diff --git a/changelog.d/unreleased/2586.fixed.md b/changelog.d/unreleased/2586.fixed.md
new file mode 100644
index 0000000000..7653247e34
--- /dev/null
+++ b/changelog.d/unreleased/2586.fixed.md
@@ -0,0 +1,16 @@
+---
+category: fixed
+issues:
+  - 2586
+affected:
+  - TESTING_GUIDE.md
+  - tests/CodeIndex.Tests/IndexCommandRunnerTests.cs
+---
+
+## English
+
+- **Documented the macOS arm64 ILLink crash skip under the tracked issue (#2586)** — the trimmed `backfill-fold` publish smoke test now reports the current SDK/ILLink crash guard against the issue that tracks the macOS AccessViolation failure.
+
+## 日本語
+
+- **macOS arm64 の ILLink crash skip を追跡 Issue に紐づけました (#2586)** — trimmed `backfill-fold` publish smoke test の SDK/ILLink crash 回避が、macOS AccessViolation failure を追跡する Issue を示すようになりました。
diff --git a/tests/CodeIndex.Tests/IndexCommandRunnerTests.cs b/tests/CodeIndex.Tests/IndexCommandRunnerTests.cs
index a18c59c14b..a105341a5a 100644
--- a/tests/CodeIndex.Tests/IndexCommandRunnerTests.cs
+++ b/tests/CodeIndex.Tests/IndexCommandRunnerTests.cs
@@ -14,7 +14,7 @@ public sealed class SkipOnMacOsArm64FactAttribute : FactAttribute
     public SkipOnMacOsArm64FactAttribute()
     {
         if (OperatingSystem.IsMacOS() && RuntimeInformation.ProcessArchitecture == Architecture.Arm64)
-            Skip = "macOS arm64 SDK/ILLink currently crashes before this test can exercise cdidx (#2570).";
+            Skip = "macOS arm64 SDK/ILLink can crash before this test can exercise cdidx (#2586).";
     }
 }