diff --git a/tests/test_litellm/managed_agents/test_subclass_override.py b/tests/test_litellm/managed_agents/test_subclass_override.py
new file mode 100644
index 00000000000..e6de3b32919
--- /dev/null
+++ b/tests/test_litellm/managed_agents/test_subclass_override.py
@@ -0,0 +1,182 @@
+"""
+Tests for subclassing ``AgentRuntime`` to add ``before_tool_call`` /
+``after_tool_call`` hooks.
+
+This is the primary extension point for callers who need to audit,
+redact, or rewrite tool calls without forking the entire runtime.
+"""
+
+import json
+from typing import Any, Dict, List
+
+import pytest
+
+from litellm.managed_agents.agent_runtime.base import AgentConfig, SessionState
+from litellm.managed_agents.agent_runtime.litellm_native import LiteLLMAgentRuntime
+from litellm.managed_agents.events import (
+    EVENT_TYPE_RUN_FINISHED,
+    EVENT_TYPE_TOOL_RESULT,
+)
+from litellm.managed_agents.sandbox.base import Sandbox, ToolResult
+
+
+class _PassthroughSandbox(Sandbox):
+    """Sandbox that echoes the tool name + input back so we can see what hook saw."""
+
+    def __init__(self):
+        self.invocations: List[Dict[str, Any]] = []
+
+    async def execute_tool(self, tool_name: str, tool_input: Dict[str, Any]):
+        self.invocations.append({"name": tool_name, "input": tool_input})
+        return ToolResult(output=f"executed {tool_name} with {tool_input!r}")
+
+
+class _AuditingRuntime(LiteLLMAgentRuntime):
+    """Subclass that records every hook fire and rewrites tool input."""
+
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+        self.before_calls: List[Dict[str, Any]] = []
+        self.after_calls: List[Dict[str, Any]] = []
+
+    async def before_tool_call(self, tool_name, tool_input):
+        self.before_calls.append({"name": tool_name, "input": dict(tool_input)})
+        # Demonstrate rewriting: append " (audited)" to any command.
+        if tool_name == "Bash" and "command" in tool_input:
+            return {**tool_input, "command": tool_input["command"] + " (audited)"}
+        return tool_input
+
+    async def after_tool_call(self, tool_name, tool_input, result):
+        self.after_calls.append(
+            {
+                "name": tool_name,
+                "input": dict(tool_input),
+                "is_error": result.is_error,
+            }
+        )
+        return result
+
+
+def _completion_with_call(call_id, name, args):
+    return {
+        "choices": [
+            {
+                "index": 0,
+                "finish_reason": "tool_calls",
+                "message": {
+                    "role": "assistant",
+                    "content": "",
+                    "tool_calls": [
+                        {
+                            "id": call_id,
+                            "type": "function",
+                            "function": {
+                                "name": name,
+                                "arguments": json.dumps(args),
+                            },
+                        }
+                    ],
+                },
+            }
+        ]
+    }
+
+
+def _completion_text(text):
+    return {
+        "choices": [
+            {
+                "index": 0,
+                "finish_reason": "stop",
+                "message": {"role": "assistant", "content": text},
+            }
+        ]
+    }
+
+
+@pytest.mark.asyncio
+async def test_before_and_after_hooks_fire_with_rewrite(monkeypatch):
+    scripted = [
+        _completion_with_call("call_1", "Bash", {"command": "ls"}),
+        _completion_text("done"),
+    ]
+    call_state = {"i": 0}
+
+    async def fake_acompletion(**kwargs):
+        i = call_state["i"]
+        call_state["i"] += 1
+        return scripted[i]
+
+    monkeypatch.setattr("litellm.acompletion", fake_acompletion)
+
+    runtime = _AuditingRuntime()
+    sandbox = _PassthroughSandbox()
+
+    events = []
+    async for ev in runtime.run(
+        prompt="run ls",
+        sandbox=sandbox,
+        session_state=SessionState(session_id="sess"),
+        agent_config=AgentConfig(name="x", model="gpt-4o-mini"),
+    ):
+        events.append(ev)
+
+    # both hooks fired exactly once (one tool call)
+    assert len(runtime.before_calls) == 1
+    assert runtime.before_calls[0]["name"] == "Bash"
+    assert runtime.before_calls[0]["input"] == {"command": "ls"}
+
+    assert len(runtime.after_calls) == 1
+    assert runtime.after_calls[0]["name"] == "Bash"
+
+    # rewrite is honoured: sandbox saw the augmented command, not the original
+    assert sandbox.invocations == [
+        {"name": "Bash", "input": {"command": "ls (audited)"}}
+    ]
+
+    # tool_result event in the stream reflects what the sandbox returned
+    tool_results = [e for e in events if e.type == EVENT_TYPE_TOOL_RESULT]
+    assert len(tool_results) == 1
+    assert "ls (audited)" in tool_results[0].data["output"]
+
+    # And we hit the terminal event at the end.
+    assert events[-1].type == EVENT_TYPE_RUN_FINISHED
+
+
+class _BeforeRaisesRuntime(LiteLLMAgentRuntime):
+    async def before_tool_call(self, tool_name, tool_input):
+        raise ValueError("nope")
+
+
+@pytest.mark.asyncio
+async def test_before_hook_raises_surfaces_as_tool_result_error(monkeypatch):
+    scripted = [
+        _completion_with_call("call_1", "Bash", {"command": "ls"}),
+        _completion_text("ok"),
+    ]
+    call_state = {"i": 0}
+
+    async def fake_acompletion(**kwargs):
+        i = call_state["i"]
+        call_state["i"] += 1
+        return scripted[i]
+
+    monkeypatch.setattr("litellm.acompletion", fake_acompletion)
+
+    runtime = _BeforeRaisesRuntime()
+    sandbox = _PassthroughSandbox()
+    events = []
+    async for ev in runtime.run(
+        prompt="run ls",
+        sandbox=sandbox,
+        session_state=SessionState(session_id="sess"),
+        agent_config=AgentConfig(name="x", model="gpt-4o-mini"),
+    ):
+        events.append(ev)
+
+    # Sandbox was never reached — the hook short-circuited.
+    assert sandbox.invocations == []
+    tool_results = [e for e in events if e.type == EVENT_TYPE_TOOL_RESULT]
+    assert len(tool_results) == 1
+    assert tool_results[0].data["is_error"] is True
+    assert "before_tool_call" in tool_results[0].data["output"]