diff --git a/.bazelignore b/.bazelignore
index bd80032f359..fd8db055725 100644
--- a/.bazelignore
+++ b/.bazelignore
@@ -27,3 +27,6 @@ venv
 
 .ijwb
 .git
+
+# This is not run by bazel at the moment
+monguard
diff --git a/.gitattributes b/.gitattributes
index 9516ca8fd87..81a3aca7bfb 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -13,5 +13,5 @@ src/mongo/bson/column/bson_column_compressed_data.inl rules-lint-ignored=true
 *.idl linguist-language=yaml
 # Do not automatically merge golden test expected output files
 jstests/**/expected_output/**/* -merge
-
+monguard/** rules-lint-ignored=true
 MODULE.bazel.lock rules-lint-ignored=true linguist-generated
diff --git a/.prettierignore b/.prettierignore
index a4b61f1ec9c..37e153ff957 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -60,3 +60,6 @@ bazel-*
 src/mongo/db/modules/enterprise/src/streams/third_party/mongocxx/dist
 # asp-js-engine is an external module copied during Docker builds
 asp-js-engine
+
+# Ignore monguard directory due to not being part of regular build
+monguard
diff --git a/bazel/format/rules_lint_format_wrapper.py b/bazel/format/rules_lint_format_wrapper.py
index afeba003162..c40acfbecb5 100644
--- a/bazel/format/rules_lint_format_wrapper.py
+++ b/bazel/format/rules_lint_format_wrapper.py
@@ -103,6 +103,7 @@ def run_prettier(
         "!./bazel-mongo",
         "!./external",
         "!./.compiledb",
+        "!./monguard",
     }
     for path in pathlib.Path(".").iterdir():
         if path.is_symlink():
@@ -113,6 +114,9 @@ def run_prettier(
             "--cache",
             "--log-level",
             "warn",
+            # Changed-files mode may include extensions prettier does not parse (for example .py, .sky).
+            # Ignore unknown files so formatter routing can continue instead of failing early.
+            "--ignore-unknown",
         ]
         if files_to_format == "all":
             command += ["."]