Update contact multiple surfaces sample (#569)

* feat: Add schema modifiers to A2uiSchemaManager

Introduces a `schema_modifiers` parameter to A2uiSchemaManager, allowing
custom callable hooks to transform schemas after loading. This enables
flexible schema customization, such as relaxing strict validation
constraints during testing.

* Update contact_multiple_surfaces sample

It updates the sample to use the A2uiSchemaManager from the a2ui-agent
python SDK.

Tested:
- [x] The `contact` lit client successfully connected to the
  `contact_multiple_surfaces` agent and rendered the response correctly.

Author: nan-yu

a2a_agents/python/a2ui_agent/src/a2ui/inference/schema/common_modifiers.py

@@ -0,0 +1,27 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+def remove_strict_validation(schema):
+  if isinstance(schema, dict):
+    new_schema = {k: remove_strict_validation(v) for k, v in schema.items()}
+    if (
+        'additionalProperties' in new_schema
+        and new_schema['additionalProperties'] is False
+    ):
+      del new_schema['additionalProperties']
+    return new_schema
+  elif isinstance(schema, list):
+    return [remove_strict_validation(item) for item in schema]
+  return schema

a2a_agents/python/a2ui_agent/src/a2ui/inference/schema/manager.py

@@ -17,7 +17,7 @@
 import logging
 import os
 import importlib.resources
-from typing import List, Dict, Any, Optional
+from typing import List, Dict, Any, Optional, Callable
 from dataclasses import dataclass, field
 from .loader import A2uiSchemaLoader, PackageLoader, FileSystemLoader
 from ..inference_strategy import InferenceStrategy
@@ -122,6 +122,7 @@ def __init__(
       custom_catalogs: Optional[List[CustomCatalogConfig]] = None,
       exclude_basic_catalog: bool = False,
       accepts_inline_catalogs: bool = False,
+      schema_modifiers: List[Callable[[Dict[str, Any]], Dict[str, Any]]] = None,
   ):
     self._version = version
     self._exclude_basic_catalog = exclude_basic_catalog
@@ -132,6 +133,7 @@ def __init__(
     self._supported_catalogs: Dict[str, A2uiCatalog] = {}
     self._catalog_example_paths: Dict[str, str] = {}
     self._basic_catalog = None
+    self._schema_modifiers = schema_modifiers
     self._load_schemas(version, custom_catalogs, basic_examples_path)
 
   @property
@@ -142,6 +144,12 @@ def accepts_inline_catalogs(self) -> bool:
   def supported_catalogs(self) -> Dict[str, A2uiCatalog]:
     return self._supported_catalogs
 
+  def _apply_modifiers(self, schema: Dict[str, Any]) -> Dict[str, Any]:
+    if self._schema_modifiers:
+      for modifier in self._schema_modifiers:
+        schema = modifier(schema)
+    return schema
+
   def _load_schemas(
       self,
       version: str,
@@ -156,13 +164,17 @@ def _load_schemas(
       )
 
     # Load server-to-client and common types schemas
-    self._server_to_client_schema = _load_basic_component(
-        version, SERVER_TO_CLIENT_SCHEMA_KEY
+    self._server_to_client_schema = self._apply_modifiers(
+        _load_basic_component(version, SERVER_TO_CLIENT_SCHEMA_KEY)
+    )
+    self._common_types_schema = self._apply_modifiers(
+        _load_basic_component(version, COMMON_TYPES_SCHEMA_KEY)
     )
-    self._common_types_schema = _load_basic_component(version, COMMON_TYPES_SCHEMA_KEY)
 
     # Process basic catalog
-    basic_catalog_schema = _load_basic_component(version, CATALOG_SCHEMA_KEY)
+    basic_catalog_schema = self._apply_modifiers(
+        _load_basic_component(version, CATALOG_SCHEMA_KEY)
+    )
     if not basic_catalog_schema:
       basic_catalog_schema = {}
 
@@ -192,14 +204,16 @@ def _load_schemas(
     # Process custom catalogs
     if custom_catalogs:
       for config in custom_catalogs:
-        custom_catalog_schema = _load_from_path(config.catalog_path)
+        custom_catalog_schema = self._apply_modifiers(
+            _load_from_path(config.catalog_path)
+        )
         resolved_catalog_schema = A2uiCatalog.resolve_schema(
             basic_catalog_schema, custom_catalog_schema
         )
         catalog = A2uiCatalog(
             version=version,
             name=config.name,
-            catalog_schema=resolved_catalog_schema,
+            catalog_schema=self._apply_modifiers(resolved_catalog_schema),
             s2c_schema=self._server_to_client_schema,
             common_types_schema=self._common_types_schema,
         )

a2a_agents/python/a2ui_agent/tests/inference/test_modifiers.py

@@ -0,0 +1,74 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import pytest
+from unittest.mock import patch
+from a2ui.inference.schema.manager import A2uiSchemaManager
+from a2ui.inference.schema.common_modifiers import remove_strict_validation
+
+
+def test_remove_strict_validation():
+  """Tests the remove_strict_validation modifier."""
+  schema = {
+      "type": "object",
+      "properties": {
+          "a": {"type": "string", "additionalProperties": False},
+          "b": {
+              "type": "array",
+              "items": {"type": "object", "additionalProperties": False},
+          },
+      },
+      "additionalProperties": False,
+  }
+
+  modified = remove_strict_validation(schema)
+
+  # Check that additionalProperties: False is removed
+  assert "additionalProperties" not in modified
+  assert "additionalProperties" not in modified["properties"]["a"]
+  assert "additionalProperties" not in modified["properties"]["b"]["items"]
+
+  # Check that it didn't mutate the original
+  assert schema["additionalProperties"] is False
+  assert schema["properties"]["a"]["additionalProperties"] is False
+
+
+def test_manager_with_modifiers():
+  """Tests that A2uiSchemaManager applies modifiers during loading."""
+  # Mock _load_basic_component to return a simple schema with strict validation
+  mock_schema = {"type": "object", "additionalProperties": False}
+  with patch(
+      "a2ui.inference.schema.manager._load_basic_component", return_value=mock_schema
+  ):
+    manager = A2uiSchemaManager("0.8", schema_modifiers=[remove_strict_validation])
+
+    # Verify that loaded schemas have modifiers applied
+    assert "additionalProperties" not in manager._server_to_client_schema
+    assert "additionalProperties" not in manager._common_types_schema
+
+    # basic catalog should also be modified
+    for catalog in manager._supported_catalogs.values():
+      assert "additionalProperties" not in catalog.catalog_schema
+
+
+def test_manager_no_modifiers():
+  """Tests that A2uiSchemaManager works fine without modifiers."""
+  mock_schema = {"type": "object", "additionalProperties": False}
+  with patch(
+      "a2ui.inference.schema.manager._load_basic_component", return_value=mock_schema
+  ):
+    manager = A2uiSchemaManager("0.8", schema_modifiers=None)
+
+    # Verify that schemas are NOT modified
+    assert manager._server_to_client_schema["additionalProperties"] is False

a2a_agents/python/a2ui_agent/tests/integration/verify_load_real.py

@@ -16,12 +16,13 @@
 
 from a2ui.inference.schema.manager import A2uiSchemaManager
 from a2ui.inference.schema.constants import CATALOG_COMPONENTS_KEY
+from a2ui.inference.schema.common_modifiers import remove_strict_validation
 
 
 def verify():
   print('Verifying A2uiSchemaManager...')
   try:
-    manager = A2uiSchemaManager('0.8')
+    manager = A2uiSchemaManager('0.8', schema_modifiers=[remove_strict_validation])
     catalog = manager.get_effective_catalog()
     catalog_components = catalog.catalog_schema[CATALOG_COMPONENTS_KEY]
     print(f'Successfully loaded 0.8: {len(catalog_components)} components')
@@ -364,6 +365,13 @@ def verify():
                         'key': 'imageUrl',
                         'valueString': 'http://localhost:10003/static/profile2.png',
                     },
+                    {
+                        'key': 'contacts',
+                        'valueMap': [{
+                            'key': 'contact1',
+                            'valueMap': [{'key': 'name', 'valueString': 'Casey Smith'}],
+                        }],
+                    },
                 ],
             }
         },
@@ -375,7 +383,7 @@ def verify():
     sys.exit(1)
 
   try:
-    manager = A2uiSchemaManager('0.9')
+    manager = A2uiSchemaManager('0.9', schema_modifiers=[remove_strict_validation])
     catalog = manager.get_effective_catalog()
     catalog_components = catalog.catalog_schema[CATALOG_COMPONENTS_KEY]
     print(f'Successfully loaded 0.9: {len(catalog_components)} components')
@@ -389,6 +397,7 @@ def verify():
                 'catalogId': (
                     'https://a2ui.dev/specification/v0_9/standard_catalog.json'
                 ),
+                'fakeProperty': 'should be allowed',
             },
         },
         {

samples/agent/adk/contact_multiple_surfaces/__main__.py

@@ -19,8 +19,6 @@
 from a2a.server.apps import A2AStarletteApplication
 from a2a.server.request_handlers import DefaultRequestHandler
 from a2a.server.tasks import InMemoryTaskStore
-from a2a.types import AgentCapabilities, AgentCard, AgentSkill
-from a2ui.extension.a2ui_extension import get_a2ui_agent_extension
 from agent import ContactAgent
 from agent_executor import ContactAgentExecutor
 from dotenv import load_dotenv
@@ -46,48 +44,22 @@ def main(host, port):
     if not os.getenv("GOOGLE_GENAI_USE_VERTEXAI") == "TRUE":
       if not os.getenv("GEMINI_API_KEY"):
         raise MissingAPIKeyError(
-            "GEMINI_API_KEY environment variable not set and GOOGLE_GENAI_USE_VERTEXAI"
-            " is not TRUE."
+            "GEMINI_API_KEY environment variable not set and"
+            " GOOGLE_GENAI_USE_VERTEXAI is not TRUE."
         )
 
-    capabilities = AgentCapabilities(
-        streaming=True,
-        extensions=[get_a2ui_agent_extension()],
-    )
-    skill = AgentSkill(
-        id="find_contact",
-        name="Find Contact Tool",
-        description=(
-            "Helps find contact information for colleagues (e.g., email, location,"
-            " team)."
-        ),
-        tags=["contact", "directory", "people", "finder"],
-        examples=["Who is David Chen in marketing?", "Find Sarah Lee from engineering"],
-    )
-
     base_url = f"http://{host}:{port}"
 
-    agent_card = AgentCard(
-        name="Contact Lookup Agent",
-        description=(
-            "This agent helps find contact info for people in your organization."
-        ),
-        url=base_url,  # <-- Use base_url here
-        version="1.0.0",
-        default_input_modes=ContactAgent.SUPPORTED_CONTENT_TYPES,
-        default_output_modes=ContactAgent.SUPPORTED_CONTENT_TYPES,
-        capabilities=capabilities,
-        skills=[skill],
-    )
+    agent = ContactAgent(base_url=base_url, use_ui=True)
 
-    agent_executor = ContactAgentExecutor(base_url=base_url)
+    agent_executor = ContactAgentExecutor(agent=agent)
 
     request_handler = DefaultRequestHandler(
         agent_executor=agent_executor,
         task_store=InMemoryTaskStore(),
     )
     server = A2AStarletteApplication(
-        agent_card=agent_card, http_handler=request_handler
+        agent_card=agent.get_agent_card(), http_handler=request_handler
     )
     import uvicorn
 

samples/agent/adk/contact_multiple_surfaces/a2ui_examples.py

@@ -18,7 +18,6 @@
 from pathlib import Path
 
 import jsonschema
-from a2ui_schema import A2UI_SCHEMA
 
 logger = logging.getLogger(__name__)
 
@@ -35,77 +34,6 @@
 FLOOR_PLAN_FILE = "floor_plan.json"
 
 
-def load_examples(base_url: str = "http://localhost:10004") -> str:
-  """
-  Loads, validates, and formats the UI examples from JSON files.
-
-  Args:
-      base_url: The base URL to replace placeholder URLs with.
-                (Currently examples have http://localhost:10004 hardcoded,
-                 but we can make this dynamic if needed).
-
-  Returns:
-      A string containing all formatted examples for the prompt.
-  """
-
-  # Pre-parse validator
-  try:
-    single_msg_schema = json.loads(A2UI_SCHEMA)
-    # Examples are typically lists of messages
-    list_schema = {"type": "array", "items": single_msg_schema}
-  except json.JSONDecodeError:
-    logger.error("Failed to parse A2UI_SCHEMA for validation")
-    list_schema = None
-
-  examples_dir = Path(os.path.dirname(__file__)) / "examples"
-  formatted_output = []
-
-  for curr_name, filename in EXAMPLE_FILES.items():
-    file_path = examples_dir / filename
-    try:
-      content = file_path.read_text(encoding="utf-8")
-
-      # basic replacement if we decide to template the URL in JSON files
-      # content = content.replace("{{BASE_URL}}", base_url)
-
-      # Validation
-      if list_schema:
-        try:
-          data = json.loads(content)
-          jsonschema.validate(instance=data, schema=list_schema)
-        except (json.JSONDecodeError, jsonschema.ValidationError) as e:
-          logger.warning(f"Example {filename} validation failed: {e}")
-
-      formatted_output.append(f"---BEGIN {curr_name}---")
-      # Handle examples that include user/model text
-      if curr_name == "ORG_CHART_EXAMPLE":
-        formatted_output.append("User: Show me the org chart for Casey Smith")
-        formatted_output.append("Model: Here is the organizational chart.")
-        formatted_output.append("---a2ui_JSON---")
-      elif curr_name == "MULTI_SURFACE_EXAMPLE":
-        formatted_output.append("User: Full profile for Casey Smith")
-        formatted_output.append(
-            "Model: Here is the full profile including contact details and org chart."
-        )
-        formatted_output.append("---a2ui_JSON---")
-      elif curr_name == "CHART_NODE_CLICK_EXAMPLE":
-        formatted_output.append(
-            'User: ACTION: chart_node_click (context: clickedNodeName="John Smith")'
-            " (from modal)"
-        )
-        formatted_output.append("Model: Here is the profile for John Smith.")
-        formatted_output.append("---a2ui_JSON---")
-
-      formatted_output.append(content.strip())
-      formatted_output.append(f"---END {curr_name}---")
-      formatted_output.append("")  # Newline
-
-    except FileNotFoundError:
-      logger.error(f"Example file not found: {file_path}")
-
-  return "\n".join(formatted_output)
-
-
 def load_floor_plan_example() -> str:
   """Loads the floor plan example specifically."""
   examples_dir = Path(os.path.dirname(__file__)) / "examples"