diff --git a/aws_doc_sdk_examples_tools/doc_gen.py b/aws_doc_sdk_examples_tools/doc_gen.py
index 69b63d0..0e2a34d 100644
--- a/aws_doc_sdk_examples_tools/doc_gen.py
+++ b/aws_doc_sdk_examples_tools/doc_gen.py
@@ -262,11 +262,14 @@ def for_root(
             pass
 
         if not incremental:
-            for path in metadata.glob("*_metadata.yaml"):
-                self.process_metadata(path)
+            self.find_and_process_metadata(metadata)
 
         return self
 
+    def find_and_process_metadata(self, metadata_path: Path):
+        for path in metadata_path.glob("*_metadata.yaml"):
+            self.process_metadata(path)
+
     def process_metadata(self, path: Path) -> "DocGen":
         if path in self._loaded:
             return self
diff --git a/aws_doc_sdk_examples_tools/test_resources/doc_gen_tributary_test/.doc_gen/config/sdks.yaml b/aws_doc_sdk_examples_tools/test_resources/doc_gen_tributary_test/.doc_gen/config/sdks.yaml
new file mode 100644
index 0000000..441eede
--- /dev/null
+++ b/aws_doc_sdk_examples_tools/test_resources/doc_gen_tributary_test/.doc_gen/config/sdks.yaml
@@ -0,0 +1,13 @@
+IAMPolicy:
+  property: json
+  syntax: json
+  sdk:
+    1:
+      long: "IAM policy"
+      short: "IAM policy"
+      guide: "IAM/latest/UserGuide/introduction.html"
+      api_ref:
+        uid: "IAMPolicy"
+        name: "&SAZR;"
+        link_template: "SomeTemplate"
+  guide: "&guide-iam-user;"
diff --git a/aws_doc_sdk_examples_tools/test_resources/doc_gen_tributary_test/.doc_gen/metadata/example_with_custom_sdk_metadata.yaml b/aws_doc_sdk_examples_tools/test_resources/doc_gen_tributary_test/.doc_gen/metadata/example_with_custom_sdk_metadata.yaml
new file mode 100644
index 0000000..f6702dd
--- /dev/null
+++ b/aws_doc_sdk_examples_tools/test_resources/doc_gen_tributary_test/.doc_gen/metadata/example_with_custom_sdk_metadata.yaml
@@ -0,0 +1,13 @@
+sts_CustomSdkExample:
+  title: This example uses an SDK from the tributary config
+  title_abbrev: This example uses an SDK from the tributary config
+  synopsis: allow a user to assume any role in your account with the access- name prefix. The role must also be tagged with the same project, team, and cost center tags as the user.
+  category: IAMPolicyCategory
+  languages:
+    IAMPolicy:
+      versions:
+        - sdk_version: 1
+          excerpts:
+            - description: test
+  services:
+    sts: {AssumeRole}
diff --git a/aws_doc_sdk_examples_tools/test_resources/doc_gen_tributary_test/.doc_gen/metadata/example_with_root_sdk_metadata.yaml b/aws_doc_sdk_examples_tools/test_resources/doc_gen_tributary_test/.doc_gen/metadata/example_with_root_sdk_metadata.yaml
new file mode 100644
index 0000000..c748309
--- /dev/null
+++ b/aws_doc_sdk_examples_tools/test_resources/doc_gen_tributary_test/.doc_gen/metadata/example_with_root_sdk_metadata.yaml
@@ -0,0 +1,13 @@
+sts_RootSdkExample:
+  title: This example uses an SDK from the root config
+  title_abbrev: This example uses an SDK from the root config
+  synopsis: allow a user to assume any role in your account with the access- name prefix. The role must also be tagged with the same project, team, and cost center tags as the user.
+  category: IAMPolicyCategory
+  languages:
+    Python:
+      versions:
+        - sdk_version: 3
+          excerpts:
+            - description: test
+  services:
+    sts: {AssumeRole}
diff --git a/aws_doc_sdk_examples_tools/validate.py b/aws_doc_sdk_examples_tools/validate.py
index 325903f..ef980c4 100755
--- a/aws_doc_sdk_examples_tools/validate.py
+++ b/aws_doc_sdk_examples_tools/validate.py
@@ -38,28 +38,35 @@ def main():
     )
     args = parser.parse_args()
     root_path = Path(args.root).resolve()
+    config_path = Path(args.config).resolve() if args.config else None
+    return validate(root_path, config_path, args.strict_titles, args.doc_gen_only)
 
-    if args.config:
-        config_path = Path(args.config).resolve()
+
+def validate(
+    root_path: Path, config_path: Path, strict: bool, doc_gen_only: bool
+) -> int:
+    if config_path is not None:
         doc_gen = DocGen.default()
-        doc_gen.merge(
-            DocGen.from_root(
-                root=root_path,
-                validation=ValidationConfig(strict_titles=args.strict_titles),
-                config=config_path,
-            )
+        doc_gen_local = DocGen.from_root(
+            root=root_path,
+            validation=ValidationConfig(strict_titles=strict),
+            config=config_path,
+            incremental=True,
         )
+        doc_gen.merge(doc_gen_local)
         doc_gen.root = root_path
+        doc_gen.errors = doc_gen_local.errors
+        metadata = doc_gen.root / ".doc_gen/metadata"
+        doc_gen.find_and_process_metadata(metadata)
     else:
         doc_gen = DocGen.from_root(
             root=root_path,
-            validation=ValidationConfig(strict_titles=args.strict_titles),
-            config=args.config,
+            validation=ValidationConfig(strict_titles=strict),
         )
 
     doc_gen.collect_snippets(snippets_root=root_path)
     doc_gen.validate()
-    if not args.doc_gen_only:
+    if not doc_gen_only:
         check_files(doc_gen.root, doc_gen.validation, doc_gen.errors)
         verify_sample_files(doc_gen.root, doc_gen.validation, doc_gen.errors)
 
diff --git a/aws_doc_sdk_examples_tools/validate_test.py b/aws_doc_sdk_examples_tools/validate_test.py
index e69de29..8d1c602 100644
--- a/aws_doc_sdk_examples_tools/validate_test.py
+++ b/aws_doc_sdk_examples_tools/validate_test.py
@@ -0,0 +1,16 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""
+Test for validate.
+"""
+
+from pathlib import Path
+
+from .validate import validate
+
+
+def test_validate():
+    root_path = Path(__file__).parent / "test_resources" / "doc_gen_tributary_test"
+    error_count = validate(root_path, root_path / ".doc_gen/config", False, False)
+    assert error_count == 0