diff --git a/python/packages/core/agent_framework/_agent_hooks.py b/python/packages/core/agent_framework/_agent_hooks.py
index 31c52f235d..a8fbdfd7f1 100644
--- a/python/packages/core/agent_framework/_agent_hooks.py
+++ b/python/packages/core/agent_framework/_agent_hooks.py
@@ -857,21 +857,44 @@ 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]
+    """Project the registered tool names for ``agent_startup`` (spec ``tools_registered``).
+
+    The projection mirrors run preparation: constructor tools, agent/run options tools,
+    and the run-level tool overrides are all combined, so a run that supplies extra
+    tools still reports the agent's configured tools alongside them.
+    """
+    from ._tools import _get_tool_name, normalize_tools  # pyright: ignore[reportPrivateUsage]
+
+    merged: list[Any] = []
+
+    def _extend(source: Any) -> None:
+        if source is None:
+            return
+        try:
+            merged.extend(normalize_tools(source))
+        except Exception:
+            logger.warning(
+                "agent-hooks could not normalize the run's tools for the agent_startup projection."
+            )
+
+    agent = context.agent
+    _extend(getattr(agent, "tools", None))
+    default_options = getattr(agent, "default_options", None)
+    if isinstance(default_options, Mapping):
+        _extend(cast(Mapping[str, Any], default_options).get("tools"))
+    options = context.options
+    if isinstance(options, Mapping):
+        _extend(cast(Mapping[str, Any], options).get("tools"))
+    _extend(context.tools)
 
-    tools: Any = context.tools if context.tools is not None else getattr(context.agent, "tools", None)
-    if tools is None:
-        return []
-    try:
-        normalized = normalize_tools(tools)
-    except Exception:
-        logger.warning("agent-hooks could not normalize the run's tools for the agent_startup projection.")
-        return []
     names: list[str] = []
-    for item in normalized:
+    seen: set[str] = set()
+    for item in merged:
         name = _get_tool_name(item)
-        names.append(name if name else type(item).__name__)
+        label = name if name else type(item).__name__
+        if label not in seen:
+            seen.add(label)
+            names.append(label)
     return names
 
 
diff --git a/python/packages/core/tests/core/test_agent_hooks.py b/python/packages/core/tests/core/test_agent_hooks.py
index a13b96baa0..44a80f88c3 100644
--- a/python/packages/core/tests/core/test_agent_hooks.py
+++ b/python/packages/core/tests/core/test_agent_hooks.py
@@ -106,6 +106,12 @@ def weather_tool(location: str) -> str:
     return f"weather in {location}"
 
 
+@tool(approval_mode="never_require")
+def search_tool(query: str) -> str:
+    """Run a search."""
+    return f"results for {query}"
+
+
 weather_tool_calls: list[str] = []
 
 
@@ -293,6 +299,40 @@ 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_agent_startup_merges_run_tools_with_constructor_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", tools=[search_tool])
+
+    startup = guard.contexts_for("agent_startup")
+    assert len(startup) == 1
+    assert startup[0]["agent_init"]["tools_registered"] == ["weather_tool", "search_tool"]
+
+
 @requires_sdk
 async def test_input_projection_is_faithful(chat_client_base: MockBaseChatClient) -> None:
     guard = AllowGuard()