chore: import upstream snapshot with attribution

python/samples/02-agents/harness/console/observers/text_output.py

@@ -0,0 +1,59 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""Text output observer for streaming agent text."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+from rich.markup import escape
+
+from .base import ConsoleObserver
+
+if TYPE_CHECKING:
+    from agent_framework import Agent
+
+    from ..state_driver import IUXStateDriver
+
+
+class TextOutputObserver(ConsoleObserver):
+    """Displays streaming text output from the agent.
+
+    Writes text chunks incrementally to the UX state driver as they arrive,
+    allowing real-time display during streaming.
+    """
+
+    async def on_text(
+        self,
+        ux: IUXStateDriver,
+        text: str,
+        agent: Agent,
+        session: Any,
+    ) -> None:
+        """Write each text chunk directly to the UX driver.
+
+        Args:
+            ux: The UX state driver for UI updates.
+            text: The text chunk to display.
+            agent: The AI agent.
+            session: The agent session.
+        """
+        ux.write_text(escape(text))
+
+    async def on_stream_complete(
+        self,
+        ux: IUXStateDriver,
+        agent: Agent,
+        session: Any,
+    ) -> list | None:
+        """No-op on stream complete (state managed by UX driver).
+
+        Args:
+            ux: The UX state driver for UI updates.
+            agent: The AI agent.
+            session: The agent session.
+
+        Returns:
+            None (no follow-up actions).
+        """
+        return None