diff --git a/.github/scripts/patch-coverage.cs b/.github/scripts/patch-coverage.cs
index be1cd435083..80f97c9947a 100644
--- a/.github/scripts/patch-coverage.cs
+++ b/.github/scripts/patch-coverage.cs
@@ -49,15 +49,21 @@
 // 2. Parse cobertura: absolute path -> (line -> hits). Merge partial-class duplicates by max hits.
 var coverage = ParseCobertura(coberturaPath);
 
-// Whole-project line coverage (every instrumented file in the report).
-var projValid = coverage.Sum(f => f.Value.Count);
-var projCovered = coverage.Sum(f => f.Value.Values.Count(h => h > 0));
+// Whole-project line coverage (production files only; test/benchmark sources are excluded).
+var prodFiles = coverage.Where(f => IsProductionPath(f.Key)).ToList();
+var projValid = prodFiles.Sum(f => f.Value.Count);
+var projCovered = prodFiles.Sum(f => f.Value.Values.Count(h => h > 0));
 var projPct = projValid == 0 ? 100.0 : 100.0 * projCovered / projValid;
 
 // 3. Intersect per file. A changed line counts only if it appears in coverage (executable).
 var rows = new List<FileRow>();
 foreach (var (path, lines) in changed.OrderBy(x => x.Key, StringComparer.Ordinal))
 {
+    if (!IsProductionPath(path))
+    {
+        continue; // patch coverage measures production code, not test/benchmark sources
+    }
+
     var hits = Match(coverage, path);
     if (hits is null)
     {
@@ -349,6 +355,16 @@ static string BuildJson(string sha, List<FileRow> withMisses)
     return b.ToString();
 }
 
+static bool IsProductionPath(string path)
+{
+    // Exclude test and benchmark sources; everything else counts as production.
+    var p = "/" + path.Replace('\\', '/') + "/";
+    return !(p.Contains("/test/", StringComparison.OrdinalIgnoreCase)
+        || p.Contains("/tests/", StringComparison.OrdinalIgnoreCase)
+        || p.Contains("/benchmark/", StringComparison.OrdinalIgnoreCase)
+        || p.Contains("/benchmarks/", StringComparison.OrdinalIgnoreCase));
+}
+
 static string Sha256Hex(string value)
 {
     var bytes = System.Security.Cryptography.SHA256.HashData(Encoding.UTF8.GetBytes(value));