diff --git a/contributing/samples/api_registry_agent/agent.py b/contributing/samples/api_registry_agent/agent.py
index 5247c9fa..9f55ef80 100644
--- a/contributing/samples/api_registry_agent/agent.py
+++ b/contributing/samples/api_registry_agent/agent.py
@@ -26,7 +26,7 @@ registry_tools = api_registry.get_toolset(
     mcp_server_name=MCP_SERVER_NAME,
 )
 root_agent = LlmAgent(
-    model="gemini-2.0-flash",
+    model="gemini-2.5-flash",
     name="bigquery_assistant",
     instruction=f"""
 You are a helpful data analyst assistant with access to BigQuery. The project ID is: {PROJECT_ID}
diff --git a/contributing/samples/mcp_dynamic_header_agent/agent.py b/contributing/samples/mcp_dynamic_header_agent/agent.py
index 17768c16..0d3ce7f6 100644
--- a/contributing/samples/mcp_dynamic_header_agent/agent.py
+++ b/contributing/samples/mcp_dynamic_header_agent/agent.py
@@ -18,7 +18,7 @@ from google.adk.tools.mcp_tool.mcp_session_manager import StreamableHTTPConnecti
 from google.adk.tools.mcp_tool.mcp_toolset import McpToolset
 
 root_agent = LlmAgent(
-    model='gemini-2.0-flash',
+    model='gemini-2.5-flash',
     name='tenant_agent',
     instruction="""You are a helpful assistant that helps users get tenant
  information. Call the get_tenant_data tool when the user asks for tenant data.""",
diff --git a/contributing/samples/mcp_postgres_agent/agent.py b/contributing/samples/mcp_postgres_agent/agent.py
index 7224c34a..09e75b44 100644
--- a/contributing/samples/mcp_postgres_agent/agent.py
+++ b/contributing/samples/mcp_postgres_agent/agent.py
@@ -31,7 +31,7 @@ if not POSTGRES_CONNECTION_STRING:
   )
 
 root_agent = LlmAgent(
-    model="gemini-2.0-flash",
+    model="gemini-2.5-flash",
     name="postgres_agent",
     instruction=(
         "You are a PostgreSQL database assistant. "
diff --git a/contributing/samples/mcp_service_account_agent/agent.py b/contributing/samples/mcp_service_account_agent/agent.py
index a62e30ce..975ff0cc 100644
--- a/contributing/samples/mcp_service_account_agent/agent.py
+++ b/contributing/samples/mcp_service_account_agent/agent.py
@@ -29,7 +29,7 @@ MCP_SERVER_URL = "https://test.sandbox.googleapis.com/mcp"
 SCOPES = {"https://www.googleapis.com/auth/cloud-platform": ""}
 
 root_agent = LlmAgent(
-    model="gemini-2.0-flash",
+    model="gemini-2.5-flash",
     name="enterprise_assistant",
     instruction="""
 Help the user with the tools available to you.
diff --git a/contributing/samples/mcp_sse_agent/agent.py b/contributing/samples/mcp_sse_agent/agent.py
index 2afbb930..8bddbca7 100755
--- a/contributing/samples/mcp_sse_agent/agent.py
+++ b/contributing/samples/mcp_sse_agent/agent.py
@@ -28,7 +28,7 @@ connection_params = SseConnectionParams(
 )
 
 root_agent = LlmAgent(
-    model='gemini-2.0-flash',
+    model='gemini-2.5-flash',
     name='enterprise_assistant',
     instruction=McpInstructionProvider(
         connection_params=connection_params,
diff --git a/contributing/samples/mcp_stdio_notion_agent/agent.py b/contributing/samples/mcp_stdio_notion_agent/agent.py
index 55ea56ec..1a624f7e 100644
--- a/contributing/samples/mcp_stdio_notion_agent/agent.py
+++ b/contributing/samples/mcp_stdio_notion_agent/agent.py
@@ -29,7 +29,7 @@ NOTION_HEADERS = json.dumps({
 })
 
 root_agent = LlmAgent(
-    model="gemini-2.0-flash",
+    model="gemini-2.5-flash",
     name="notion_agent",
     instruction=(
         "You are my workspace assistant. "
diff --git a/contributing/samples/mcp_stdio_server_agent/agent.py b/contributing/samples/mcp_stdio_server_agent/agent.py
index 1799bd56..8b336ba2 100755
--- a/contributing/samples/mcp_stdio_server_agent/agent.py
+++ b/contributing/samples/mcp_stdio_server_agent/agent.py
@@ -23,7 +23,7 @@ from mcp import StdioServerParameters
 _allowed_path = os.path.dirname(os.path.abspath(__file__))
 
 root_agent = LlmAgent(
-    model='gemini-2.0-flash',
+    model='gemini-2.5-flash',
     name='enterprise_assistant',
     instruction=f"""\
 Help user accessing their file systems.
diff --git a/contributing/samples/mcp_streamablehttp_agent/agent.py b/contributing/samples/mcp_streamablehttp_agent/agent.py
index e2223b0f..1da782d0 100644
--- a/contributing/samples/mcp_streamablehttp_agent/agent.py
+++ b/contributing/samples/mcp_streamablehttp_agent/agent.py
@@ -22,7 +22,7 @@ from google.adk.tools.mcp_tool.mcp_toolset import MCPToolset
 _allowed_path = os.path.dirname(os.path.abspath(__file__))
 
 root_agent = LlmAgent(
-    model='gemini-2.0-flash',
+    model='gemini-2.5-flash',
     name='enterprise_assistant',
     instruction=f"""\
 Help user accessing their file systems.