chore: import upstream snapshot with attribution

examples/integrations/a2a-a2ui/a2ui_extension/.gitignore

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examples/integrations/a2a-a2ui/a2ui_extension/README.md

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+# A2UI Extension Implementation
+
+This is the Python implementation of the a2ui extension.
+
+## Disclaimer
+
+Important: The sample code provided is for demonstration purposes and illustrates the mechanics of the Agent-to-Agent (A2A) protocol. When building production applications, it is critical to treat any agent operating outside of your direct control as a potentially untrusted entity.
+
+All data received from an external agent—including but not limited to its AgentCard, messages, artifacts, and task statuses—should be handled as untrusted input. For example, a malicious agent could provide an AgentCard containing crafted data in its fields (e.g., description, name, skills.description). If this data is used without sanitization to construct prompts for a Large Language Model (LLM), it could expose your application to prompt injection attacks. Failure to properly validate and sanitize this data before use can introduce security vulnerabilities into your application.
+
+Developers are responsible for implementing appropriate security measures, such as input validation and secure handling of credentials to protect their systems and users.

examples/integrations/a2a-a2ui/a2ui_extension/pyproject.toml

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+[project]
+name = "a2ui"
+version = "0.1.0"
+description = "A2UI Extension"
+readme = "README.md"
+requires-python = ">=3.10"
+dependencies = ["a2a-sdk>=0.3.0"]
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"

examples/integrations/a2a-a2ui/a2ui_extension/src/a2ui/__init__.py

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+# Copyright 2025 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.

examples/integrations/a2a-a2ui/a2ui_extension/src/a2ui/a2ui_extension.py

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+# Copyright 2025 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 logging
+from typing import Any, Optional
+
+from a2a.server.agent_execution import RequestContext
+from a2a.types import AgentExtension, Part, DataPart
+
+logger = logging.getLogger(__name__)
+
+A2UI_EXTENSION_URI = "https://a2ui.org/a2a-extension/a2ui/v0.8"
+
+MIME_TYPE_KEY = "mimeType"
+A2UI_MIME_TYPE = "application/json+a2ui"
+
+A2UI_CLIENT_CAPABILITIES_KEY = "a2uiClientCapabilities"
+SUPPORTED_CATALOG_IDS_KEY = "supportedCatalogIds"
+INLINE_CATALOGS_KEY = "inlineCatalogs"
+
+STANDARD_CATALOG_ID = "https://raw.githubusercontent.com/google/A2UI/refs/heads/main/specification/0.8/json/standard_catalog_definition.json"
+
+
+def create_a2ui_part(a2ui_data: dict[str, Any]) -> Part:
+    """Creates an A2A Part containing A2UI data.
+
+    Args:
+        a2ui_data: The A2UI data dictionary.
+
+    Returns:
+        An A2A Part with a DataPart containing the A2UI data.
+    """
+    return Part(
+        root=DataPart(
+            data=a2ui_data,
+            metadata={
+                MIME_TYPE_KEY: A2UI_MIME_TYPE,
+            },
+        )
+    )
+
+
+def is_a2ui_part(part: Part) -> bool:
+    """Checks if an A2A Part contains A2UI data.
+
+    Args:
+        part: The A2A Part to check.
+
+    Returns:
+        True if the part contains A2UI data, False otherwise.
+    """
+    return (
+        isinstance(part.root, DataPart)
+        and part.root.metadata
+        and part.root.metadata.get(MIME_TYPE_KEY) == A2UI_MIME_TYPE
+    )
+
+
+def get_a2ui_datapart(part: Part) -> Optional[DataPart]:
+    """Extracts the DataPart containing A2UI data from an A2A Part, if present.
+
+    Args:
+        part: The A2A Part to extract A2UI data from.
+
+    Returns:
+        The DataPart containing A2UI data if present, None otherwise.
+    """
+    if is_a2ui_part(part):
+        return part.root
+    return None
+
+
+def get_a2ui_agent_extension(
+    accepts_inline_custom_catalog: bool = False,
+) -> AgentExtension:
+    """Creates the A2UI AgentExtension configuration.
+
+    Args:
+        accepts_inline_custom_catalog: Whether the agent accepts inline custom catalogs.
+
+    Returns:
+        The configured A2UI AgentExtension.
+    """
+    params = {}
+    if accepts_inline_custom_catalog:
+        params["acceptsInlineCustomCatalog"] = True  # Only set if not default of False
+
+    return AgentExtension(
+        uri=A2UI_EXTENSION_URI,
+        description="Provides agent driven UI using the A2UI JSON format.",
+        params=params if params else None,
+    )
+
+
+def try_activate_a2ui_extension(context: RequestContext) -> bool:
+    """Activates the A2UI extension if requested.
+
+    Args:
+        context: The request context to check.
+
+    Returns:
+        True if activated, False otherwise.
+    """
+    if A2UI_EXTENSION_URI in context.requested_extensions:
+        context.add_activated_extension(A2UI_EXTENSION_URI)
+        return True
+    return False

examples/integrations/a2a-a2ui/a2ui_extension/tests/__init__.py

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+# Copyright 2025 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
+#
+#     http://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.

examples/integrations/a2a-a2ui/a2ui_extension/tests/test_extension.py

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+# Copyright 2025 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.
+
+
+from a2a.server.agent_execution import RequestContext
+from a2a.types import DataPart, TextPart, Part
+from a2ui import a2ui_extension
+
+from unittest.mock import MagicMock
+
+
+def test_a2ui_part_serialization():
+    a2ui_data = {"beginRendering": {"surfaceId": "test-surface", "root": "root-column"}}
+
+    part = a2ui_extension.create_a2ui_part(a2ui_data)
+
+    assert a2ui_extension.is_a2ui_part(part), "Should be identified as A2UI part"
+
+    data_part = a2ui_extension.get_a2ui_datapart(part)
+    assert data_part is not None, "Should contain DataPart"
+    assert a2ui_data == data_part.data, "Deserialized data should match original"
+
+
+def test_non_a2ui_data_part():
+    part = Part(
+        root=DataPart(
+            data={"foo": "bar"},
+            metadata={"mimeType": "application/json"},  # Not A2UI
+        )
+    )
+    assert not a2ui_extension.is_a2ui_part(part), (
+        "Should not be identified as A2UI part"
+    )
+    assert a2ui_extension.get_a2ui_datapart(part) is None, (
+        "Should not return A2UI DataPart"
+    )
+
+
+def test_non_a2ui_part():
+    text_part = TextPart(text="this is some text")
+    part = Part(root=text_part)
+
+    assert not a2ui_extension.is_a2ui_part(part), (
+        "Should not be identified as A2UI part"
+    )
+    assert a2ui_extension.get_a2ui_datapart(part) is None, (
+        "Should not return A2UI DataPart"
+    )
+
+
+def test_get_a2ui_agent_extension():
+    agent_extension = a2ui_extension.get_a2ui_agent_extension()
+    assert agent_extension.uri == a2ui_extension.A2UI_EXTENSION_URI
+    assert agent_extension.params is None
+
+
+def test_get_a2ui_agent_extension_with_inline_custom_catalog():
+    agent_extension = a2ui_extension.get_a2ui_agent_extension(
+        accepts_inline_custom_catalog=True
+    )
+    assert agent_extension.uri == a2ui_extension.A2UI_EXTENSION_URI
+    assert agent_extension.params is not None
+
+
+def test_try_activate_a2ui_extension():
+    context = MagicMock(spec=RequestContext)
+    context.requested_extensions = [a2ui_extension.A2UI_EXTENSION_URI]
+
+    assert a2ui_extension.try_activate_a2ui_extension(context)
+    context.add_activated_extension.assert_called_once_with(
+        a2ui_extension.A2UI_EXTENSION_URI
+    )
+
+
+def test_try_activate_a2ui_extension_not_requested():
+    context = MagicMock(spec=RequestContext)
+    context.requested_extensions = []
+
+    assert not a2ui_extension.try_activate_a2ui_extension(context)
+    context.add_activated_extension.assert_not_called()