diff --git a/codex-rs/app-server/BUILD.bazel b/codex-rs/app-server/BUILD.bazel
index 6ec98e92d5..2e0c25d4fd 100644
--- a/codex-rs/app-server/BUILD.bazel
+++ b/codex-rs/app-server/BUILD.bazel
@@ -18,7 +18,11 @@ codex_rust_crate(
         # long. Using a higher shard count for app-server-all-test should help
         # mitigate this risk.
         "app-server-all-test": 32,
+        "app-server-all-test-windows-cross": 16,
         "app-server-unit-tests": 8,
     },
+    test_sizes = {
+        "app-server-all-test-windows-cross": "medium",
+    },
     test_tags = ["no-sandbox"],
 )
diff --git a/codex-rs/core/BUILD.bazel b/codex-rs/core/BUILD.bazel
index ff972618f1..ad58af2a81 100644
--- a/codex-rs/core/BUILD.bazel
+++ b/codex-rs/core/BUILD.bazel
@@ -44,8 +44,13 @@ codex_rust_crate(
     ],
     test_shard_counts = {
         "core-all-test": 16,
-        "core-all-test-windows-cross": 32,
+        "core-all-test-windows-cross": 8,
         "core-unit-tests": 16,
+        "core-unit-tests-windows-cross": 8,
+    },
+    test_sizes = {
+        "core-all-test-windows-cross": "medium",
+        "core-unit-tests-windows-cross": "medium",
     },
     test_tags = ["no-sandbox"],
 )
diff --git a/codex-rs/exec/BUILD.bazel b/codex-rs/exec/BUILD.bazel
index b4926fc346..2a4f722156 100644
--- a/codex-rs/exec/BUILD.bazel
+++ b/codex-rs/exec/BUILD.bazel
@@ -5,6 +5,10 @@ codex_rust_crate(
     crate_name = "codex_exec",
     test_shard_counts = {
         "exec-all-test": 16,
+        "exec-all-test-windows-cross": 2,
+    },
+    test_sizes = {
+        "exec-all-test-windows-cross": "medium",
     },
     test_tags = ["no-sandbox"],
 )
diff --git a/codex-rs/utils/image/BUILD.bazel b/codex-rs/utils/image/BUILD.bazel
index d101a9f870..b16cfe1a23 100644
--- a/codex-rs/utils/image/BUILD.bazel
+++ b/codex-rs/utils/image/BUILD.bazel
@@ -5,5 +5,9 @@ codex_rust_crate(
     crate_name = "codex_utils_image",
     test_shard_counts = {
         "image-unit-tests": 4,
+        "image-unit-tests-windows-cross": 1,
+    },
+    test_sizes = {
+        "image-unit-tests-windows-cross": "medium",
     },
 )