feat: add tenant to ServerCallContext, add tenant-prefixed routes for REST endpoints

 and introduce tenant extraction from REST API paths

Author: sokoliva

src/a2a/server/agent_execution/context.py

@@ -160,6 +160,11 @@ def add_activated_extension(self, uri: str) -> None:
         if self._call_context:
             self._call_context.activated_extensions.add(uri)
 
+    @property
+    def tenant(self) -> str:
+        """The tenant associated with this request."""
+        return self._call_context.tenant if self._call_context else ''
+
     @property
     def requested_extensions(self) -> set[str]:
         """Extensions that the client requested to activate."""

src/a2a/server/apps/rest/rest_adapter.py

@@ -111,6 +111,9 @@ async def _handle_request(
         request: Request,
     ) -> Response:
         call_context = self._context_builder.build(request)
+        if 'tenant' in request.path_params:
+            call_context.tenant = request.path_params['tenant']
+
         response = await method(request, call_context)
         return JSONResponse(content=response)
 
@@ -131,6 +134,8 @@ async def _handle_streaming_request(
             ) from e
 
         call_context = self._context_builder.build(request)
+        if 'tenant' in request.path_params:
+            call_context.tenant = request.path_params['tenant']
 
         async def event_generator(
             stream: AsyncIterable[Any],
@@ -250,10 +255,59 @@ def routes(self) -> dict[tuple[str, str], Callable[[Request], Any]]:
             ('/tasks', 'GET'): functools.partial(
                 self._handle_request, self.handler.list_tasks
             ),
+            # Tenant prefixed routes
+            ('/{tenant}/message:send', 'POST'): functools.partial(
+                self._handle_request,
+                self.handler.on_message_send,
+            ),
+            ('/{tenant}/message:stream', 'POST'): functools.partial(
+                self._handle_streaming_request,
+                self.handler.on_message_send_stream,
+            ),
+            ('/{tenant}/tasks/{id}:cancel', 'POST'): functools.partial(
+                self._handle_request, self.handler.on_cancel_task
+            ),
+            ('/{tenant}/tasks/{id}:subscribe', 'GET'): functools.partial(
+                self._handle_streaming_request,
+                self.handler.on_subscribe_to_task,
+            ),
+            ('/{tenant}/tasks/{id}', 'GET'): functools.partial(
+                self._handle_request, self.handler.on_get_task
+            ),
+            (
+                '/{tenant}/tasks/{id}/pushNotificationConfigs/{push_id}',
+                'GET',
+            ): functools.partial(
+                self._handle_request, self.handler.get_push_notification
+            ),
+            (
+                '/{tenant}/tasks/{id}/pushNotificationConfigs/{push_id}',
+                'DELETE',
+            ): functools.partial(
+                self._handle_request, self.handler.delete_push_notification
+            ),
+            (
+                '/{tenant}/tasks/{id}/pushNotificationConfigs',
+                'POST',
+            ): functools.partial(
+                self._handle_request, self.handler.set_push_notification
+            ),
+            (
+                '/{tenant}/tasks/{id}/pushNotificationConfigs',
+                'GET',
+            ): functools.partial(
+                self._handle_request, self.handler.list_push_notifications
+            ),
+            ('/{tenant}/tasks', 'GET'): functools.partial(
+                self._handle_request, self.handler.list_tasks
+            ),
         }
         if self.agent_card.capabilities.extended_agent_card:
             routes[('/extendedAgentCard', 'GET')] = functools.partial(
                 self._handle_request, self.handle_authenticated_agent_card
             )
+            routes[('/{tenant}/extendedAgentCard', 'GET')] = functools.partial(
+                self._handle_request, self.handle_authenticated_agent_card
+            )
 
         return routes

src/a2a/server/context.py

@@ -21,5 +21,6 @@ class ServerCallContext(BaseModel):
 
     state: State = Field(default={})
     user: User = Field(default=UnauthenticatedUser())
+    tenant: str = Field(default='')
     requested_extensions: set[str] = Field(default_factory=set)
     activated_extensions: set[str] = Field(default_factory=set)

tests/server/apps/rest/test_rest_tenant.py

@@ -0,0 +1,99 @@
+import pytest
+from unittest.mock import MagicMock
+from fastapi import FastAPI
+from httpx import ASGITransport, AsyncClient
+from google.protobuf import json_format
+
+from a2a.server.apps.rest.fastapi_app import A2ARESTFastAPIApplication
+from a2a.server.request_handlers.request_handler import RequestHandler
+from a2a.types.a2a_pb2 import (
+    AgentCard,
+    Message,
+    Role,
+    Part,
+    SendMessageRequest,
+    SendMessageConfiguration,
+)
+
+
+@pytest.fixture
+async def agent_card() -> AgentCard:
+    mock_agent_card = MagicMock(spec=AgentCard)
+    mock_agent_card.url = 'http://mockurl.com'
+    mock_capabilities = MagicMock()
+    mock_capabilities.streaming = False
+    mock_agent_card.capabilities = mock_capabilities
+    return mock_agent_card
+
+
+@pytest.fixture
+async def request_handler() -> RequestHandler:
+    handler = MagicMock(spec=RequestHandler)
+    # Return a default response so the test doesn't crash on return value expectation
+    handler.on_message_send.return_value = Message(
+        message_id='test',
+        role=Role.ROLE_AGENT,
+        parts=[Part(text='response message')],
+    )
+    return handler
+
+
+@pytest.fixture
+async def app(
+    agent_card: AgentCard, request_handler: RequestHandler
+) -> FastAPI:
+    return A2ARESTFastAPIApplication(agent_card, request_handler).build(
+        agent_card_url='/well-known/agent.json', rpc_url=''
+    )
+
+
+@pytest.fixture
+async def client(app: FastAPI) -> AsyncClient:
+    return AsyncClient(transport=ASGITransport(app=app), base_url='http://test')
+
+
+@pytest.mark.anyio
+async def test_tenant_extraction_from_path(
+    client: AsyncClient, request_handler: MagicMock
+) -> None:
+    request = SendMessageRequest(
+        message=Message(),
+        configuration=SendMessageConfiguration(),
+    )
+
+    # Test with tenant in URL
+    tenant_id = 'my-tenant-123'
+    response = await client.post(
+        f'/{tenant_id}/message:send', json=json_format.MessageToDict(request)
+    )
+    response.raise_for_status()
+
+    # Verify handler was called
+    assert request_handler.on_message_send.called
+
+    # Verify call context has tenant
+    args, _ = request_handler.on_message_send.call_args
+    # args[0] is the request proto, args[1] is the ServerCallContext
+    context = args[1]
+    assert context.tenant == tenant_id
+
+
+@pytest.mark.anyio
+async def test_no_tenant_extraction(
+    client: AsyncClient, request_handler: MagicMock
+) -> None:
+    request = SendMessageRequest(
+        message=Message(),
+        configuration=SendMessageConfiguration(),
+    )
+
+    # Test without tenant in URL
+    response = await client.post(
+        '/message:send', json=json_format.MessageToDict(request)
+    )
+    response.raise_for_status()
+
+    # Verify call context has empty string tenant (default)
+    args, _ = request_handler.on_message_send.call_args
+    context = args[1]
+    assert context.tenant == ''