diff --git a/examples/dogfooding/agent.py b/examples/dogfooding/agent.py
index eae6cdcf..aee43544 100644
--- a/examples/dogfooding/agent.py
+++ b/examples/dogfooding/agent.py
@@ -24,6 +24,7 @@
 import os
 
 from veadk import Agent
+from veadk.utils.pdf_to_images import pdf_to_images_before_model_callback
 
 # The schema mirrors the web UI's AgentDraft and the codegen catalog
 # (frontend/src/create/veadkCatalog.ts). Output values MUST come from the
@@ -90,6 +91,7 @@
     name="agent_builder",
     description="VeADK Agent Builder：把自然语言需求转化为智能体配置 JSON（前端据此生成 VeADK 项目）。",
     instruction=lambda _ctx: INSTRUCTION,
+    before_model_callback=pdf_to_images_before_model_callback,
     **({"model_name": _MODEL_A} if _MODEL_A else {}),
 )
 
diff --git a/examples/dogfooding_b/agent.py b/examples/dogfooding_b/agent.py
index b746fc35..27133726 100644
--- a/examples/dogfooding_b/agent.py
+++ b/examples/dogfooding_b/agent.py
@@ -24,6 +24,7 @@
 import os
 
 from veadk import Agent
+from veadk.utils.pdf_to_images import pdf_to_images_before_model_callback
 
 # The two builder apps share one instruction. ADK puts the agents dir on
 # sys.path, so the sibling app package is importable; fall back to the
@@ -39,6 +40,7 @@
     name="agent_builder_b",
     description="VeADK Agent Builder (B)：A/B 对比中的第二个构建器。",
     instruction=lambda _ctx: INSTRUCTION,
+    before_model_callback=pdf_to_images_before_model_callback,
     **({"model_name": _MODEL_B} if _MODEL_B else {}),
 )
 
diff --git a/examples/front_with_sso/agent.py b/examples/front_with_sso/agent.py
index ef8a132c..9433d0ae 100644
--- a/examples/front_with_sso/agent.py
+++ b/examples/front_with_sso/agent.py
@@ -20,11 +20,13 @@
 """
 
 from veadk import Agent
+from veadk.utils.pdf_to_images import pdf_to_images_before_model_callback
 
 agent = Agent(
     name="sso_demo_agent",
     description="Demo agent served behind an SSO login page.",
     instruction="You are a helpful assistant. Answer concisely.",
+    before_model_callback=pdf_to_images_before_model_callback,
 )
 
 # Required by the Google ADK agent loader.
diff --git a/examples/web_demo/agent.py b/examples/web_demo/agent.py
index 8491b589..d3774a65 100644
--- a/examples/web_demo/agent.py
+++ b/examples/web_demo/agent.py
@@ -24,6 +24,7 @@
 """
 
 from veadk import Agent
+from veadk.utils.pdf_to_images import pdf_to_images_before_model_callback
 
 agent = Agent(
     name="web_demo",
@@ -32,6 +33,7 @@
         "You are a helpful assistant. Answer clearly and concisely in the "
         "user's language."
     ),
+    before_model_callback=pdf_to_images_before_model_callback,
 )
 
 # Required by the ADK agent loader.