diff --git a/python/packages/core/agent_framework/_agent_hooks.py b/python/packages/core/agent_framework/_agent_hooks.py
index 669cdb262a..71fe28884f 100644
--- a/python/packages/core/agent_framework/_agent_hooks.py
+++ b/python/packages/core/agent_framework/_agent_hooks.py
@@ -857,9 +857,15 @@ def _agent_updates_from_response(response: AgentResponse[Any]) -> list[AgentResp
 
 def _tool_names(context: AgentContext) -> list[str]:
     """Project the registered tool names for ``agent_startup`` (spec ``tools_registered``)."""
-    from ._tools import _get_tool_name, normalize_tools  # type: ignore[reportPrivateUsage]
+    from ._tools import _get_tool_name, normalize_tools  # pyright: ignore[reportPrivateUsage]
 
-    tools: Any = context.tools if context.tools is not None else getattr(context.agent, "tools", None)
+    if context.tools is not None:
+        tools: Any = context.tools
+    else:
+        tools = getattr(context.agent, "tools", None)
+        default_options = getattr(context.agent, "default_options", None)
+        if tools is None and isinstance(default_options, Mapping):
+            tools = cast(Any, cast(Mapping[str, Any], default_options).get("tools"))
     if tools is None:
         return []
     try:
diff --git a/python/packages/core/tests/core/test_agent_hooks.py b/python/packages/core/tests/core/test_agent_hooks.py
index 347d7bae4f..de347f3836 100644
--- a/python/packages/core/tests/core/test_agent_hooks.py
+++ b/python/packages/core/tests/core/test_agent_hooks.py
@@ -275,6 +275,22 @@ async def test_full_tool_run_emits_complete_ordered_session(chat_client_base: Mo
     assert pre_tool["tool_call"]["id"] == "call_1"
 
 
+@requires_sdk
+async def test_agent_startup_projects_constructor_registered_tools(chat_client_base: MockBaseChatClient) -> None:
+    guard = AllowGuard()
+    agent = Agent(
+        client=chat_client_base,
+        tools=[weather_tool],
+        middleware=[create_agent_hooks_middleware([guard])],
+    )
+
+    await agent.run("hello")
+
+    startup = guard.contexts_for("agent_startup")
+    assert len(startup) == 1
+    assert startup[0]["agent_init"]["tools_registered"] == ["weather_tool"]
+
+
 @requires_sdk
 async def test_input_projection_is_faithful(chat_client_base: MockBaseChatClient) -> None:
     guard = AllowGuard()