From 7dd8a81f13afae4085e0666ff027c9ca4e91cc6f Mon Sep 17 00:00:00 2001
From: Andrew Asseily <nyandrew@amazon.com>
Date: Tue, 17 Mar 2026 14:24:23 -0400
Subject: [PATCH 1/5] Filter unmodeled fields from error output

---
 awscli/botocore/client.py           |  7 +++
 awscli/errorhandler.py              | 42 +++++++++++++----
 tests/unit/test_structured_error.py | 73 +++++++++++++++++++++++++++++
 3 files changed, 113 insertions(+), 9 deletions(-)

diff --git a/awscli/botocore/client.py b/awscli/botocore/client.py
index b04b3f5c70c5..dc645df85dbc 100644
--- a/awscli/botocore/client.py
+++ b/awscli/botocore/client.py
@@ -903,6 +903,13 @@ def _make_api_call(self, operation_name, api_params):
 
         if http.status_code >= 300:
             error_code = parsed_response.get("Error", {}).get("Code")
+            error_shape = self._service_model.shape_for_error_code(
+                error_code
+            )
+            modeled_fields = {'Code', 'Message'}
+            if error_shape:
+                modeled_fields |= set(error_shape.members.keys())
+            parsed_response['ModeledErrorFields'] = modeled_fields
             error_class = self.exceptions.from_code(error_code)
             raise error_class(parsed_response, operation_name)
         else:
diff --git a/awscli/errorhandler.py b/awscli/errorhandler.py
index 5453d1194deb..e23c2e07da5e 100644
--- a/awscli/errorhandler.py
+++ b/awscli/errorhandler.py
@@ -49,8 +49,10 @@
 
 
 class EnhancedErrorFormatter:
-    def format_error(self, error_info, stream):
-        additional_fields = self._get_additional_fields(error_info)
+    def format_error(self, error_info, stream, modeled_fields=None):
+        additional_fields = self._get_additional_fields(
+            error_info, modeled_fields
+        )
 
         if not additional_fields:
             return
@@ -94,9 +96,19 @@ def _format_inline(self, value):
             return f'{{{items}}}'
         return str(value)
 
-    def _get_additional_fields(self, error_info):
-        standard_keys = {'Code', 'Message'}
-        return {k: v for k, v in error_info.items() if k not in standard_keys}
+    def _get_additional_fields(self, error_info, modeled_fields=None):
+        standard_keys = {'code', 'message'}
+        if modeled_fields is not None:
+            return {
+                k: v
+                for k, v in error_info.items()
+                if k.lower() not in standard_keys and k in modeled_fields
+            }
+        return {
+            k: v
+            for k, v in error_info.items()
+            if k.lower() not in standard_keys
+        }
 
 
 def construct_entry_point_handlers_chain():
@@ -200,6 +212,7 @@ def _display_structured_error(
     ):
         try:
             error_format = self._resolve_error_format(parsed_globals)
+            modeled_fields = error_info.pop('_modeled_fields', None)
 
             if error_format == 'legacy':
                 return False
@@ -213,7 +226,9 @@ def _display_structured_error(
 
             if error_format == 'enhanced':
                 write_error(stderr, formatted_message)
-                EnhancedErrorFormatter().format_error(error_info, stderr)
+                EnhancedErrorFormatter().format_error(
+                    error_info, stderr, modeled_fields
+                )
                 return True
 
             color = getattr(parsed_globals, 'color', 'auto')
@@ -275,7 +290,10 @@ def _get_formatted_message(self, error_info, exception):
     def _extract_error_info(self, exception):
         error_response = self._extract_error_response(exception)
         if error_response and 'Error' in error_response:
-            return error_response['Error']
+            error_info = error_response['Error']
+            modeled_fields = error_response.get('ModeledErrorFields')
+            error_info['_modeled_fields'] = modeled_fields
+            return error_info
         return None
 
     @staticmethod
@@ -291,12 +309,18 @@ def _extract_error_response(exception):
             # not nested under an Error key. Botocore preserves this structure.
             # Include these fields to provide complete error information.
             # Exclude response metadata and avoid duplicates.
-            excluded_keys = {'Error', 'ResponseMetadata', 'Code', 'Message'}
+            excluded_keys = {'Error', 'ResponseMetadata', 'Code', 'Message',
+                             'ModeledErrorFields'}
             for key, value in exception.response.items():
                 if key not in excluded_keys and key not in error_dict:
                     error_dict[key] = value
 
-            return {'Error': error_dict}
+            result = {'Error': error_dict}
+            if 'ModeledErrorFields' in exception.response:
+                result['ModeledErrorFields'] = exception.response[
+                    'ModeledErrorFields'
+                ]
+            return result
 
         return None
 
diff --git a/tests/unit/test_structured_error.py b/tests/unit/test_structured_error.py
index edd1241c4674..9bc7a5464950 100644
--- a/tests/unit/test_structured_error.py
+++ b/tests/unit/test_structured_error.py
@@ -150,6 +150,47 @@ def test_error_format_case_insensitive(self):
         )
         assert stderr.getvalue() == expected
 
+    def test_modeled_fields_filters_unmodeled_from_display(self):
+        error_response = {
+            'Error': {
+                'Code': 'ExpiredToken',
+                'Message': 'Token expired',
+                'Token-0': 'AQoDYXdzEJr...sensitive...',
+            },
+            'ResponseMetadata': {'RequestId': '123'},
+            'ModeledErrorFields': {'Code', 'Message'},
+        }
+        client_error = ClientError(error_response, 'ListBuckets')
+
+        stdout = io.StringIO()
+        stderr = io.StringIO()
+
+        rc = self.handler.handle_exception(client_error, stdout, stderr)
+
+        assert rc == CLIENT_ERROR_RC
+        assert 'Token-0' not in stderr.getvalue()
+        assert 'sensitive' not in stderr.getvalue()
+
+    def test_modeled_fields_not_leaked_in_json_format(self):
+        error_response = {
+            'Error': {
+                'Code': 'ExpiredToken',
+                'Message': 'Token expired',
+            },
+            'ResponseMetadata': {'RequestId': '123'},
+            'ModeledErrorFields': {'Code', 'Message'},
+        }
+        client_error = ClientError(error_response, 'ListBuckets')
+
+        self.session.session_vars['cli_error_format'] = 'json'
+
+        stdout = io.StringIO()
+        stderr = io.StringIO()
+
+        self.handler.handle_exception(client_error, stdout, stderr)
+
+        assert '_modeled_fields' not in stderr.getvalue()
+
 
 class TestEnhancedErrorFormatter:
     def setup_method(self):
@@ -343,6 +384,38 @@ def test_format_error_with_unicode_and_special_chars(self):
         )
         assert output == expected
 
+    def test_format_error_hides_unmodeled_fields(self):
+        error_info = {
+            'Code': 'ExpiredToken',
+            'Message': 'Token expired',
+            'Token-0': 'AQoDYXdzEJr...sensitive...',
+        }
+
+        stream = io.StringIO()
+        self.formatter.format_error(
+            error_info, stream, modeled_fields={'Code', 'Message'}
+        )
+
+        assert stream.getvalue() == ''
+
+    def test_format_error_shows_modeled_fields(self):
+        error_info = {
+            'Code': 'FileSystemNotFound',
+            'Message': 'Not found',
+            'ErrorCode': 'FileSystemNotFound',
+            'UnmodeledField': 'should be hidden',
+        }
+
+        stream = io.StringIO()
+        self.formatter.format_error(
+            error_info, stream,
+            modeled_fields={'Code', 'Message', 'ErrorCode'},
+        )
+
+        output = stream.getvalue()
+        assert 'ErrorCode: FileSystemNotFound' in output
+        assert 'UnmodeledField' not in output
+
     def test_format_error_with_large_list(self):
         error_info = {
             'Code': 'LargeList',

From 0958880b25e628c1fe2a634191abccf531a7e2a7 Mon Sep 17 00:00:00 2001
From: Andrew Asseily <nyandrew@amazon.com>
Date: Tue, 17 Mar 2026 14:31:45 -0400
Subject: [PATCH 2/5] Add changelog entry

---
 .changes/next-release/bugfix-errorformatting-83208.json | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changes/next-release/bugfix-errorformatting-83208.json

diff --git a/.changes/next-release/bugfix-errorformatting-83208.json b/.changes/next-release/bugfix-errorformatting-83208.json
new file mode 100644
index 000000000000..7225afce4b5d
--- /dev/null
+++ b/.changes/next-release/bugfix-errorformatting-83208.json
@@ -0,0 +1,5 @@
+{
+  "type": "bugfix",
+  "category": "error formatting",
+  "description": "Error output now only displays modeled error fields in the 'Additional error details' section."
+}

From b6a951e06eedf68f313182d3fd6c62234e3614ed Mon Sep 17 00:00:00 2001
From: Andrew Asseily <nyandrew@amazon.com>
Date: Tue, 17 Mar 2026 15:15:02 -0400
Subject: [PATCH 3/5] move modeled_fields to exception attribute,
 case-insensitive filtering, return empty dict for unknown modeled fields

---
 awscli/botocore/client.py           |  5 +-
 awscli/errorhandler.py              | 22 +++------
 tests/unit/test_structured_error.py | 72 ++++++++++++++++++++++++-----
 3 files changed, 70 insertions(+), 29 deletions(-)

diff --git a/awscli/botocore/client.py b/awscli/botocore/client.py
index dc645df85dbc..c67485d62266 100644
--- a/awscli/botocore/client.py
+++ b/awscli/botocore/client.py
@@ -909,9 +909,10 @@ def _make_api_call(self, operation_name, api_params):
             modeled_fields = {'Code', 'Message'}
             if error_shape:
                 modeled_fields |= set(error_shape.members.keys())
-            parsed_response['ModeledErrorFields'] = modeled_fields
             error_class = self.exceptions.from_code(error_code)
-            raise error_class(parsed_response, operation_name)
+            error = error_class(parsed_response, operation_name)
+            error.modeled_fields = modeled_fields
+            raise error
         else:
             return parsed_response
 
diff --git a/awscli/errorhandler.py b/awscli/errorhandler.py
index e23c2e07da5e..fefecb75b239 100644
--- a/awscli/errorhandler.py
+++ b/awscli/errorhandler.py
@@ -99,16 +99,14 @@ def _format_inline(self, value):
     def _get_additional_fields(self, error_info, modeled_fields=None):
         standard_keys = {'code', 'message'}
         if modeled_fields is not None:
+            modeled_lower = {f.lower() for f in modeled_fields}
             return {
                 k: v
                 for k, v in error_info.items()
-                if k.lower() not in standard_keys and k in modeled_fields
+                if k.lower() not in standard_keys
+                and k.lower() in modeled_lower
             }
-        return {
-            k: v
-            for k, v in error_info.items()
-            if k.lower() not in standard_keys
-        }
+        return {}
 
 
 def construct_entry_point_handlers_chain():
@@ -291,7 +289,7 @@ def _extract_error_info(self, exception):
         error_response = self._extract_error_response(exception)
         if error_response and 'Error' in error_response:
             error_info = error_response['Error']
-            modeled_fields = error_response.get('ModeledErrorFields')
+            modeled_fields = getattr(exception, 'modeled_fields', None)
             error_info['_modeled_fields'] = modeled_fields
             return error_info
         return None
@@ -309,18 +307,12 @@ def _extract_error_response(exception):
             # not nested under an Error key. Botocore preserves this structure.
             # Include these fields to provide complete error information.
             # Exclude response metadata and avoid duplicates.
-            excluded_keys = {'Error', 'ResponseMetadata', 'Code', 'Message',
-                             'ModeledErrorFields'}
+            excluded_keys = {'Error', 'ResponseMetadata', 'Code', 'Message'}
             for key, value in exception.response.items():
                 if key not in excluded_keys and key not in error_dict:
                     error_dict[key] = value
 
-            result = {'Error': error_dict}
-            if 'ModeledErrorFields' in exception.response:
-                result['ModeledErrorFields'] = exception.response[
-                    'ModeledErrorFields'
-                ]
-            return result
+            return {'Error': error_dict}
 
         return None
 
diff --git a/tests/unit/test_structured_error.py b/tests/unit/test_structured_error.py
index 9bc7a5464950..6410597da7c3 100644
--- a/tests/unit/test_structured_error.py
+++ b/tests/unit/test_structured_error.py
@@ -53,6 +53,7 @@ def test_displays_structured_error_with_additional_members(self):
             'ResponseMetadata': {'RequestId': '123'},
         }
         client_error = ClientError(error_response, 'GetObject')
+        client_error.modeled_fields = {'Code', 'Message', 'BucketName'}
 
         stdout = io.StringIO()
         stderr = io.StringIO()
@@ -129,6 +130,7 @@ def test_error_format_case_insensitive(self):
             'ResponseMetadata': {'RequestId': '123'},
         }
         client_error = ClientError(error_response, 'GetObject')
+        client_error.modeled_fields = {'Code', 'Message', 'BucketName'}
 
         self.session.config_store.set_config_provider(
             'cli_error_format', mock.Mock(provide=lambda: 'Enhanced')
@@ -158,9 +160,9 @@ def test_modeled_fields_filters_unmodeled_from_display(self):
                 'Token-0': 'AQoDYXdzEJr...sensitive...',
             },
             'ResponseMetadata': {'RequestId': '123'},
-            'ModeledErrorFields': {'Code', 'Message'},
         }
         client_error = ClientError(error_response, 'ListBuckets')
+        client_error.modeled_fields = {'Code', 'Message'}
 
         stdout = io.StringIO()
         stderr = io.StringIO()
@@ -178,9 +180,9 @@ def test_modeled_fields_not_leaked_in_json_format(self):
                 'Message': 'Token expired',
             },
             'ResponseMetadata': {'RequestId': '123'},
-            'ModeledErrorFields': {'Code', 'Message'},
         }
         client_error = ClientError(error_response, 'ListBuckets')
+        client_error.modeled_fields = {'Code', 'Message'}
 
         self.session.session_vars['cli_error_format'] = 'json'
 
@@ -190,6 +192,47 @@ def test_modeled_fields_not_leaked_in_json_format(self):
         self.handler.handle_exception(client_error, stdout, stderr)
 
         assert '_modeled_fields' not in stderr.getvalue()
+        assert 'modeled_fields' not in stderr.getvalue()
+
+    def test_no_modeled_fields_hides_additional_fields(self):
+        # ClientError without modeled_fields attribute (e.g. manually
+        # constructed in customizations) should not show additional fields.
+        error_response = {
+            'Error': {
+                'Code': 'CustomError',
+                'Message': 'Something broke',
+                'Detail': 'extra info',
+            },
+            'ResponseMetadata': {'RequestId': '123'},
+        }
+        client_error = ClientError(error_response, 'DoThing')
+
+        stdout = io.StringIO()
+        stderr = io.StringIO()
+
+        self.handler.handle_exception(client_error, stdout, stderr)
+
+        assert 'Detail' not in stderr.getvalue()
+
+    def test_modeled_fields_case_insensitive_match(self):
+        # Model has 'ErrorCode' but response has 'errorCode' (or vice versa)
+        error_response = {
+            'Error': {
+                'Code': 'SomeError',
+                'Message': 'msg',
+                'errorcode': 'detail',
+            },
+            'ResponseMetadata': {'RequestId': '123'},
+        }
+        client_error = ClientError(error_response, 'Op')
+        client_error.modeled_fields = {'Code', 'Message', 'ErrorCode'}
+
+        stdout = io.StringIO()
+        stderr = io.StringIO()
+
+        self.handler.handle_exception(client_error, stdout, stderr)
+
+        assert 'errorcode: detail' in stderr.getvalue()
 
 
 class TestEnhancedErrorFormatter:
@@ -203,7 +246,7 @@ def test_format_error_with_no_additional_fields(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         assert output == ''
@@ -217,7 +260,7 @@ def test_format_error_with_simple_fields(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         expected = (
@@ -236,7 +279,7 @@ def test_format_error_with_small_list(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         expected = (
@@ -254,7 +297,7 @@ def test_format_error_with_small_dict(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         expected = (
@@ -272,7 +315,7 @@ def test_format_error_with_complex_object(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         expected = (
@@ -295,7 +338,7 @@ def test_format_error_with_nested_dict(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         expected = (
@@ -324,7 +367,7 @@ def test_format_error_with_list_of_dicts(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         expected = (
@@ -348,7 +391,7 @@ def test_format_error_with_mixed_types(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         expected = (
@@ -372,7 +415,7 @@ def test_format_error_with_unicode_and_special_chars(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         expected = (
@@ -424,7 +467,7 @@ def test_format_error_with_large_list(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream)
+        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
 
         output = stream.getvalue()
         expected = (
@@ -471,6 +514,9 @@ def test_dynamodb_transaction_cancelled_error(self):
             },
         }
         client_error = ClientError(error_response, 'TransactWriteItems')
+        client_error.modeled_fields = {
+            'Code', 'Message', 'CancellationReasons',
+        }
 
         stdout = io.StringIO()
         stderr = io.StringIO()
@@ -514,6 +560,7 @@ def test_error_handler_receives_parsed_globals_from_clidriver(self):
             'ResponseMetadata': {'RequestId': '123'},
         }
         client_error = ClientError(error_response, 'GetObject')
+        client_error.modeled_fields = {'Code', 'Message', 'BucketName'}
 
         stdout = io.StringIO()
         stderr = io.StringIO()
@@ -544,6 +591,7 @@ def test_error_handler_without_parsed_globals_uses_default(self):
             'ResponseMetadata': {'RequestId': '123'},
         }
         client_error = ClientError(error_response, 'GetObject')
+        client_error.modeled_fields = {'Code', 'Message', 'BucketName'}
 
         stdout = io.StringIO()
         stderr = io.StringIO()

From 25cfb4026244991b1796ad5f79bb50654d55c0da Mon Sep 17 00:00:00 2001
From: Andrew Asseily <nyandrew@amazon.com>
Date: Tue, 17 Mar 2026 15:30:44 -0400
Subject: [PATCH 4/5] Filter unmodeled error fields from all CLI output formats

---
 awscli/botocore/client.py           |  1 +
 awscli/errorhandler.py              | 37 ++++++++++++++-----------
 tests/unit/test_structured_error.py | 42 ++++++++++++++---------------
 3 files changed, 43 insertions(+), 37 deletions(-)

diff --git a/awscli/botocore/client.py b/awscli/botocore/client.py
index c67485d62266..ed78f75661af 100644
--- a/awscli/botocore/client.py
+++ b/awscli/botocore/client.py
@@ -903,6 +903,7 @@ def _make_api_call(self, operation_name, api_params):
 
         if http.status_code >= 300:
             error_code = parsed_response.get("Error", {}).get("Code")
+            # Lookup is a cached dict access; only runs on error path.
             error_shape = self._service_model.shape_for_error_code(
                 error_code
             )
diff --git a/awscli/errorhandler.py b/awscli/errorhandler.py
index fefecb75b239..a13daa528663 100644
--- a/awscli/errorhandler.py
+++ b/awscli/errorhandler.py
@@ -49,10 +49,8 @@
 
 
 class EnhancedErrorFormatter:
-    def format_error(self, error_info, stream, modeled_fields=None):
-        additional_fields = self._get_additional_fields(
-            error_info, modeled_fields
-        )
+    def format_error(self, error_info, stream):
+        additional_fields = self._get_additional_fields(error_info)
 
         if not additional_fields:
             return
@@ -96,17 +94,13 @@ def _format_inline(self, value):
             return f'{{{items}}}'
         return str(value)
 
-    def _get_additional_fields(self, error_info, modeled_fields=None):
+    def _get_additional_fields(self, error_info):
         standard_keys = {'code', 'message'}
-        if modeled_fields is not None:
-            modeled_lower = {f.lower() for f in modeled_fields}
-            return {
-                k: v
-                for k, v in error_info.items()
-                if k.lower() not in standard_keys
-                and k.lower() in modeled_lower
-            }
-        return {}
+        return {
+            k: v
+            for k, v in error_info.items()
+            if k.lower() not in standard_keys
+        }
 
 
 def construct_entry_point_handlers_chain():
@@ -212,6 +206,19 @@ def _display_structured_error(
             error_format = self._resolve_error_format(parsed_globals)
             modeled_fields = error_info.pop('_modeled_fields', None)
 
+            if modeled_fields is not None:
+                modeled_lower = {f.lower() for f in modeled_fields}
+                for key in list(error_info.keys()):
+                    if key.lower() not in modeled_lower:
+                        del error_info[key]
+            else:
+                # No model info available (e.g. manually constructed
+                # ClientError). Remove all non-standard fields.
+                standard = {'code', 'message'}
+                for key in list(error_info.keys()):
+                    if key.lower() not in standard:
+                        del error_info[key]
+
             if error_format == 'legacy':
                 return False
 
@@ -225,7 +232,7 @@ def _display_structured_error(
             if error_format == 'enhanced':
                 write_error(stderr, formatted_message)
                 EnhancedErrorFormatter().format_error(
-                    error_info, stderr, modeled_fields
+                    error_info, stderr
                 )
                 return True
 
diff --git a/tests/unit/test_structured_error.py b/tests/unit/test_structured_error.py
index 6410597da7c3..cfede75aedce 100644
--- a/tests/unit/test_structured_error.py
+++ b/tests/unit/test_structured_error.py
@@ -178,6 +178,7 @@ def test_modeled_fields_not_leaked_in_json_format(self):
             'Error': {
                 'Code': 'ExpiredToken',
                 'Message': 'Token expired',
+                'Token-0': 'AQoDYXdzEJr...sensitive...',
             },
             'ResponseMetadata': {'RequestId': '123'},
         }
@@ -191,8 +192,10 @@ def test_modeled_fields_not_leaked_in_json_format(self):
 
         self.handler.handle_exception(client_error, stdout, stderr)
 
-        assert '_modeled_fields' not in stderr.getvalue()
-        assert 'modeled_fields' not in stderr.getvalue()
+        parsed = json.loads(stderr.getvalue())
+        assert 'Token-0' not in parsed
+        assert '_modeled_fields' not in parsed
+        assert 'modeled_fields' not in parsed
 
     def test_no_modeled_fields_hides_additional_fields(self):
         # ClientError without modeled_fields attribute (e.g. manually
@@ -246,7 +249,7 @@ def test_format_error_with_no_additional_fields(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         assert output == ''
@@ -260,7 +263,7 @@ def test_format_error_with_simple_fields(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         expected = (
@@ -279,7 +282,7 @@ def test_format_error_with_small_list(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         expected = (
@@ -297,7 +300,7 @@ def test_format_error_with_small_dict(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         expected = (
@@ -315,7 +318,7 @@ def test_format_error_with_complex_object(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         expected = (
@@ -338,7 +341,7 @@ def test_format_error_with_nested_dict(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         expected = (
@@ -367,7 +370,7 @@ def test_format_error_with_list_of_dicts(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         expected = (
@@ -391,7 +394,7 @@ def test_format_error_with_mixed_types(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         expected = (
@@ -415,7 +418,7 @@ def test_format_error_with_unicode_and_special_chars(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         expected = (
@@ -428,36 +431,31 @@ def test_format_error_with_unicode_and_special_chars(self):
         assert output == expected
 
     def test_format_error_hides_unmodeled_fields(self):
+        # Unmodeled fields are now filtered before reaching the formatter.
+        # Formatter receives only modeled fields.
         error_info = {
             'Code': 'ExpiredToken',
             'Message': 'Token expired',
-            'Token-0': 'AQoDYXdzEJr...sensitive...',
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(
-            error_info, stream, modeled_fields={'Code', 'Message'}
-        )
+        self.formatter.format_error(error_info, stream)
 
         assert stream.getvalue() == ''
 
     def test_format_error_shows_modeled_fields(self):
+        # Unmodeled fields are filtered before reaching the formatter.
         error_info = {
             'Code': 'FileSystemNotFound',
             'Message': 'Not found',
             'ErrorCode': 'FileSystemNotFound',
-            'UnmodeledField': 'should be hidden',
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(
-            error_info, stream,
-            modeled_fields={'Code', 'Message', 'ErrorCode'},
-        )
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         assert 'ErrorCode: FileSystemNotFound' in output
-        assert 'UnmodeledField' not in output
 
     def test_format_error_with_large_list(self):
         error_info = {
@@ -467,7 +465,7 @@ def test_format_error_with_large_list(self):
         }
 
         stream = io.StringIO()
-        self.formatter.format_error(error_info, stream, modeled_fields=set(error_info.keys()))
+        self.formatter.format_error(error_info, stream)
 
         output = stream.getvalue()
         expected = (

From 183ba88da17d9d1f39005001d73ba6764e1f077e Mon Sep 17 00:00:00 2001
From: Andrew Asseily <nyandrew@amazon.com>
Date: Wed, 18 Mar 2026 12:51:03 -0400
Subject: [PATCH 5/5] Formatting

---
 awscli/errorhandler.py              | 4 +---
 tests/unit/test_structured_error.py | 4 +++-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/awscli/errorhandler.py b/awscli/errorhandler.py
index a13daa528663..f22fbf671df6 100644
--- a/awscli/errorhandler.py
+++ b/awscli/errorhandler.py
@@ -231,9 +231,7 @@ def _display_structured_error(
 
             if error_format == 'enhanced':
                 write_error(stderr, formatted_message)
-                EnhancedErrorFormatter().format_error(
-                    error_info, stderr
-                )
+                EnhancedErrorFormatter().format_error(error_info, stderr)
                 return True
 
             color = getattr(parsed_globals, 'color', 'auto')
diff --git a/tests/unit/test_structured_error.py b/tests/unit/test_structured_error.py
index cfede75aedce..6b113ca1b56c 100644
--- a/tests/unit/test_structured_error.py
+++ b/tests/unit/test_structured_error.py
@@ -513,7 +513,9 @@ def test_dynamodb_transaction_cancelled_error(self):
         }
         client_error = ClientError(error_response, 'TransactWriteItems')
         client_error.modeled_fields = {
-            'Code', 'Message', 'CancellationReasons',
+            'Code',
+            'Message',
+            'CancellationReasons',
         }
 
         stdout = io.StringIO()