From 0e7ecaa9391bf2c72a62599c685330ddaec422cf Mon Sep 17 00:00:00 2001
From: jayy-77 <1427jay@gmail.com>
Date: Sat, 7 Feb 2026 03:17:45 +0530
Subject: [PATCH] plugin_framework fix

---
 src/google/adk/plugins/base_plugin.py    | 21 +++++++++++++++++++++
 src/google/adk/plugins/plugin_manager.py | 22 ++++++++++++++++++++++
 src/google/adk/runners.py                | 12 ++++++++++++
 3 files changed, 55 insertions(+)

diff --git a/src/google/adk/plugins/base_plugin.py b/src/google/adk/plugins/base_plugin.py
index 3639f61aa2..ac30fb1218 100644
--- a/src/google/adk/plugins/base_plugin.py
+++ b/src/google/adk/plugins/base_plugin.py
@@ -370,3 +370,24 @@ async def on_tool_error_callback(
       allows the original error to be raised.
     """
     pass
+
+  async def on_state_change_callback(
+      self,
+      *,
+      invocation_context: InvocationContext,
+      state_delta: dict[str, Any],
+  ) -> None:
+    """Callback executed when session state changes via event.actions.state_delta.
+
+    This callback is invoked whenever an event with a non-empty state_delta
+    is yielded from the runner, allowing plugins to observe and log state
+    changes. The callback is observational only - the return value is ignored.
+
+    Args:
+      invocation_context: The context for the entire invocation.
+      state_delta: A copy of the state changes. Plugins should not mutate this.
+
+    Returns:
+      None
+    """
+    pass
diff --git a/src/google/adk/plugins/plugin_manager.py b/src/google/adk/plugins/plugin_manager.py
index c781e8fa4e..d5fbfc6002 100644
--- a/src/google/adk/plugins/plugin_manager.py
+++ b/src/google/adk/plugins/plugin_manager.py
@@ -52,6 +52,7 @@
     "after_model_callback",
     "on_tool_error_callback",
     "on_model_error_callback",
+    "on_state_change_callback",
 ]
 
 logger = logging.getLogger("google_adk." + __name__)
@@ -257,6 +258,27 @@ async def run_on_tool_error_callback(
         error=error,
     )
 
+  async def run_on_state_change_callback(
+      self,
+      *,
+      invocation_context: InvocationContext,
+      state_delta: dict[str, Any],
+  ) -> None:
+    """Runs the `on_state_change_callback` for all plugins.
+
+    Args:
+      invocation_context: The invocation context.
+      state_delta: A copy of the state changes.
+
+    Returns:
+      None. This callback is observational only.
+    """
+    await self._run_callbacks(
+        "on_state_change_callback",
+        invocation_context=invocation_context,
+        state_delta=state_delta,
+    )
+
   async def _run_callbacks(
       self, callback_name: PluginCallbackName, **kwargs: Any
   ) -> Optional[Any]:
diff --git a/src/google/adk/runners.py b/src/google/adk/runners.py
index 545a0e83e6..14cec07a70 100644
--- a/src/google/adk/runners.py
+++ b/src/google/adk/runners.py
@@ -840,8 +840,20 @@ async def _exec_with_plugin(
                 modified_event, invocation_context.run_config
             )
             yield modified_event
+            # Detect state_delta changes after yielding the modified event
+            if modified_event.actions.state_delta:
+              await plugin_manager.run_on_state_change_callback(
+                  invocation_context=invocation_context,
+                  state_delta=modified_event.actions.state_delta.copy(),
+              )
           else:
             yield event
+            # Detect state_delta changes after yielding the original event
+            if event.actions.state_delta:
+              await plugin_manager.run_on_state_change_callback(
+                  invocation_context=invocation_context,
+                  state_delta=event.actions.state_delta.copy(),
+              )
 
     # Step 4: Run the after_run callbacks to perform global cleanup tasks or
     # finalizing logs and metrics data.