diff --git a/pre_commit/clientlib/validate_base.py b/pre_commit/clientlib/validate_base.py
index 656431b2..adcfc641 100644
--- a/pre_commit/clientlib/validate_base.py
+++ b/pre_commit/clientlib/validate_base.py
@@ -21,9 +21,9 @@ def is_regex_valid(regex):
 
 
 def get_validator(
-    json_schema,
-    exception_type,
-    additional_validation_strategy=lambda obj: None,
+        json_schema,
+        exception_type,
+        additional_validation_strategy=lambda obj: None,
 ):
     """Returns a function which will validate a yaml file for correctness
 
@@ -44,14 +44,14 @@ def get_validator(
             obj = load_strategy(file_contents)
         except Exception as e:
             raise exception_type(
-                'File {0} is not a valid yaml file'.format(filename), e,
+                'Invalid yaml: {0}\n{1}'.format(os.path.relpath(filename), e),
             )
 
         try:
             jsonschema.validate(obj, json_schema)
         except jsonschema.exceptions.ValidationError as e:
             raise exception_type(
-                'File {0} is not a valid file'.format(filename), e,
+                'Invalid content: {0}\n{1}'.format(os.path.relpath(filename), e),
             )
 
         obj = apply_defaults(obj, json_schema)
diff --git a/tox.ini b/tox.ini
index 87082d9e..ca14ff82 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,3 +23,6 @@ deps =
     sphinx
 changedir = docs
 commands = sphinx-build -b html -d build/doctrees source build/html
+
+[flake8]
+max-line-length=131