diff --git a/conservancy_beancount/errors.py b/conservancy_beancount/errors.py
index 157e151..c42ac31 100644
--- a/conservancy_beancount/errors.py
+++ b/conservancy_beancount/errors.py
@@ -67,26 +67,13 @@ class ConfigurationError(Error):
 
 
 class InvalidMetadataError(Error):
-    def __init__(self, txn, post, key, value=None, source=None):
-        if value is None:
-            msg_fmt = "{post.account} missing {key}"
-        else:
-            msg_fmt = "{post.account} has invalid {key}: {value}"
-        super().__init__(
-            msg_fmt.format(post=post, key=key, value=value),
-            txn,
-            source,
-        )
-
-
-class InvalidEntityError(InvalidMetadataError):
-    def __init__(self, txn, post=None, key='entity', value=None, source=None):
+    def __init__(self, txn, key, value=None, post=None, source=None):
         if post is None:
             srcname = 'transaction'
         else:
             srcname = post.account
         if value is None:
-            msg = "{} missing entity".format(srcname)
+            msg = "{} missing {}".format(srcname, key)
         else:
-            msg = "{} entity malformed: {}".format(srcname, value)
-        super(InvalidMetadataError, self).__init__(msg, txn, source)
+            msg = "{} has invalid {}: {}".format(srcname, key, value)
+        super().__init__(msg, txn, source)
diff --git a/conservancy_beancount/plugin/core.py b/conservancy_beancount/plugin/core.py
index 6699da9..f0e7f65 100644
--- a/conservancy_beancount/plugin/core.py
+++ b/conservancy_beancount/plugin/core.py
@@ -217,7 +217,7 @@ class _NormalizePostingMetadataHook(_PostingHook):
     # a value string from METADATA_ENUM, or else raise InvalidMetadataError.
     # This base implementation does the latter.
     def _default_value(self, txn: Transaction, post: data.Posting) -> MetaValueEnum:
-        raise errormod.InvalidMetadataError(txn, post, self.METADATA_KEY)
+        raise errormod.InvalidMetadataError(txn, self.METADATA_KEY, None, post)
 
     def post_run(self, txn: Transaction, post: data.Posting) -> errormod.Iter:
         source_value = post.meta.get(self.METADATA_KEY)
@@ -233,7 +233,7 @@ class _NormalizePostingMetadataHook(_PostingHook):
                 set_value = self.VALUES_ENUM[source_value]
             except KeyError:
                 error = errormod.InvalidMetadataError(
-                    txn, post, self.METADATA_KEY, source_value,
+                    txn, self.METADATA_KEY, source_value, post,
                 )
         if error is None:
             post.meta[self.METADATA_KEY] = set_value
diff --git a/conservancy_beancount/plugin/meta_entity.py b/conservancy_beancount/plugin/meta_entity.py
index 7fe87d8..93fb67c 100644
--- a/conservancy_beancount/plugin/meta_entity.py
+++ b/conservancy_beancount/plugin/meta_entity.py
@@ -37,14 +37,14 @@ class MetaEntity(core.TransactionHook):
         else:
             txn_entity_ok = False
         if txn_entity_ok is False:
-            yield errormod.InvalidEntityError(txn, value=txn_entity)
+            yield errormod.InvalidMetadataError(txn, self.METADATA_KEY, txn_entity)
         for post in data.iter_postings(txn):
             if post.account.is_under('Assets', 'Liabilities'):
                 continue
             entity = post.meta.get(self.METADATA_KEY)
             if entity is None:
-                yield errormod.InvalidEntityError(txn, post)
+                yield errormod.InvalidMetadataError(txn, self.METADATA_KEY, entity, post)
             elif entity is txn_entity:
                 pass
             elif not self.ENTITY_RE.match(entity):
-                yield errormod.InvalidEntityError(txn, post, value=entity)
+                yield errormod.InvalidMetadataError(txn, self.METADATA_KEY, entity, post)
diff --git a/conservancy_beancount/plugin/meta_income_type.py b/conservancy_beancount/plugin/meta_income_type.py
index fd87b37..73038b6 100644
--- a/conservancy_beancount/plugin/meta_income_type.py
+++ b/conservancy_beancount/plugin/meta_income_type.py
@@ -49,4 +49,4 @@ class MetaIncomeType(core._NormalizePostingMetadataHook):
         try:
             return self.DEFAULT_VALUES[post.account]
         except KeyError:
-            raise errormod.InvalidMetadataError(txn, post, self.METADATA_KEY) from None
+            raise errormod.InvalidMetadataError(txn, self.METADATA_KEY, None, post) from None
diff --git a/conservancy_beancount/plugin/meta_project.py b/conservancy_beancount/plugin/meta_project.py
index 5194534..cde952d 100644
--- a/conservancy_beancount/plugin/meta_project.py
+++ b/conservancy_beancount/plugin/meta_project.py
@@ -87,5 +87,4 @@ class MetaProject(core._NormalizePostingMetadataHook):
         ):
             return self.DEFAULT_PROJECT
         else:
-            raise errormod.InvalidMetadataError(txn, post, self.METADATA_KEY)
-
+            raise errormod.InvalidMetadataError(txn, self.METADATA_KEY, None, post)
diff --git a/tests/test_meta_entity.py b/tests/test_meta_entity.py
index c0902d2..3a0c6c1 100644
--- a/tests/test_meta_entity.py
+++ b/tests/test_meta_entity.py
@@ -60,7 +60,7 @@ def test_invalid_values_on_postings(hook, src_value):
     ])
     errors = list(hook.run(txn))
     assert len(errors) == 1
-    assert errors[0].message == "Expenses:General entity malformed: {}".format(src_value)
+    assert errors[0].message == "Expenses:General has invalid entity: {}".format(src_value)
 
 @pytest.mark.parametrize('src_value', VALID_VALUES)
 def test_valid_values_on_transactions(hook, src_value):
@@ -78,7 +78,7 @@ def test_invalid_values_on_transactions(hook, src_value):
     ])
     errors = list(hook.run(txn))
     assert 1 <= len(errors) <= 2
-    assert all(error.message == "transaction entity malformed: {}".format(src_value)
+    assert all(error.message == "transaction has invalid entity: {}".format(src_value)
                for error in hook.run(txn))
 
 @pytest.mark.parametrize('account,required', [