chore: import upstream snapshot with attribution

contributing/samples/workflows/state/agent.py

@@ -0,0 +1,57 @@
+# 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
+#
+#     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.
+
+
+from google.adk import Event
+from google.adk import Workflow
+
+
+def process_initial_input(ctx, node_input: str):
+  """Takes initial input and sets it in state via direct dict modification."""
+  ctx.state["original_text"] = node_input
+  return node_input
+
+
+def update_state_via_event(node_input: str):
+  """Returns an Event that implicitly updates the shared workflow state."""
+  yield Event(state={"uppercased_text": node_input.upper()})
+
+
+def read_state_via_ctx(ctx):
+  """Reads a state variable via direct dictionary access and appends to it."""
+  original = ctx.state["original_text"]
+  uppercased = ctx.state["uppercased_text"]
+
+  result = f"{uppercased} (Original was: {original})"
+  ctx.state["appended_text"] = result
+  return result
+
+
+def read_state_via_param(appended_text: str):
+  """Reads a state variable via automatic parameter injection."""
+  return f"Final Result: {appended_text}!"
+
+
+root_agent = Workflow(
+    name="state_sample",
+    edges=[
+        (
+            "START",
+            process_initial_input,
+            update_state_via_event,
+            read_state_via_ctx,
+            read_state_via_param,
+        ),
+    ],
+)