diff --git a/features/memory_service_clock_wait.feature b/features/memory_service_clock_wait.feature
new file mode 100644
index 000000000..a3af193f1
--- /dev/null
+++ b/features/memory_service_clock_wait.feature
@@ -0,0 +1,25 @@
+Feature: Memory service clock-advance guard determinism
+  As a CleverAgents developer
+  I want the _wait_for_clock_advance() helper to behave deterministically
+  So that entity-tracking tests never produce spurious timestamp failures on fast CI runners
+
+  # This feature verifies the monotonic busy-wait helper introduced in
+  # features/steps/memory_service_coverage_steps.py to replace the four
+  # bare time.sleep(0.01) guards that caused intermittent timestamp failures
+  # on heavily-loaded CI runners (issue #9963).
+  #
+  # The helper spins on the monotonic clock until the UTC clock has advanced
+  # past the supplied `before` timestamp, raising AssertionError if the
+  # deadline is exceeded.
+
+  @mock_only
+  Scenario: Clock-advance guard raises AssertionError when deadline is exceeded
+    Given a zero-second clock-advance deadline
+    When I invoke the clock-advance guard with a future timestamp
+    Then an AssertionError should be raised mentioning the deadline
+
+  @mock_only
+  Scenario: Clock-advance guard returns successfully once the clock advances
+    Given the UTC clock will advance on the next check
+    When I invoke the clock-advance guard with the current timestamp
+    Then the guard should return without raising
diff --git a/features/steps/memory_service_clock_wait_steps.py b/features/steps/memory_service_clock_wait_steps.py
new file mode 100644
index 000000000..9ca1cd0e2
--- /dev/null
+++ b/features/steps/memory_service_clock_wait_steps.py
@@ -0,0 +1,77 @@
+"""Step definitions for memory_service_clock_wait.feature.
+
+Verifies the _wait_for_clock_advance() helper introduced in
+memory_service_coverage_steps.py raises AssertionError when the deadline
+is exceeded, and returns normally once the clock actually advances.
+"""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime, timedelta
+from typing import Any
+
+from behave import given, then, when
+
+from features.steps.memory_service_coverage_steps import _wait_for_clock_advance
+
+
+@given("a zero-second clock-advance deadline")
+def step_zero_second_deadline(context: Any) -> None:
+    """Store a zero-second deadline for use in subsequent steps."""
+    context.clock_advance_deadline = 0.0
+
+
+@when("I invoke the clock-advance guard with a future timestamp")
+def step_invoke_guard_with_future_timestamp(context: Any) -> None:
+    """Call _wait_for_clock_advance with a timestamp far in the future.
+
+    Because the deadline is 0 seconds, the guard should immediately raise
+    AssertionError — the clock cannot advance past a future timestamp
+    before the deadline expires.
+    """
+    # Use a timestamp one hour in the future so the guard can never succeed.
+    future = datetime.now(UTC) + timedelta(hours=1)
+    context.clock_advance_error = None
+    try:
+        _wait_for_clock_advance(future, deadline_secs=context.clock_advance_deadline)
+    except AssertionError as exc:
+        context.clock_advance_error = exc
+
+
+@then("an AssertionError should be raised mentioning the deadline")
+def step_assert_error_raised(context: Any) -> None:
+    """Verify the guard raised AssertionError with the expected message."""
+    assert context.clock_advance_error is not None, (
+        "_wait_for_clock_advance() should have raised AssertionError but did not"
+    )
+    assert "Clock did not advance" in str(context.clock_advance_error), (
+        f"AssertionError message missing expected text: {context.clock_advance_error}"
+    )
+
+
+@given("the UTC clock will advance on the next check")
+def step_clock_will_advance(context: Any) -> None:
+    """Capture the current UTC timestamp; the clock will advance naturally."""
+    context.before_timestamp = datetime.now(UTC)
+
+
+@when("I invoke the clock-advance guard with the current timestamp")
+def step_invoke_guard_current_timestamp(context: Any) -> None:
+    """Call _wait_for_clock_advance with the captured timestamp.
+
+    The guard should return normally once the UTC clock advances past
+    context.before_timestamp, which will happen within milliseconds.
+    """
+    context.clock_advance_error = None
+    try:
+        _wait_for_clock_advance(context.before_timestamp, deadline_secs=2.0)
+    except AssertionError as exc:
+        context.clock_advance_error = exc
+
+
+@then("the guard should return without raising")
+def step_guard_returns_normally(context: Any) -> None:
+    """Verify the guard returned without raising an error."""
+    assert context.clock_advance_error is None, (
+        f"_wait_for_clock_advance() raised unexpectedly: {context.clock_advance_error}"
+    )
diff --git a/features/steps/memory_service_coverage_steps.py b/features/steps/memory_service_coverage_steps.py
index 5e8143aff..9a190068d 100644
--- a/features/steps/memory_service_coverage_steps.py
+++ b/features/steps/memory_service_coverage_steps.py
@@ -6,7 +6,7 @@ import asyncio
 import shutil
 import tempfile
 import time
-from datetime import UTC
+from datetime import UTC, datetime
 from pathlib import Path
 from typing import Any
 from unittest.mock import patch
@@ -24,6 +24,22 @@ from cleveragents.application.services.memory_service import (
 )
 
 
+def _wait_for_clock_advance(before: datetime, deadline_secs: float = 2.0) -> None:
+    """Spin until the UTC clock advances past *before*, bounded by deadline.
+
+    Uses the monotonic clock for the deadline check so the guard itself is
+    immune to wall-clock adjustments.  Raises ``AssertionError`` if the UTC
+    clock has not advanced within ``deadline_secs`` seconds.
+    """
+    deadline = time.monotonic() + deadline_secs
+    while datetime.now(UTC) <= before:
+        if time.monotonic() > deadline:
+            raise AssertionError(
+                f"Clock did not advance past {before} within {deadline_secs}s"
+            )
+        time.sleep(0.001)
+
+
 @given("a conversation adapter configured to return text values")
 def step_adapter_returning_text(context: Any) -> None:
     """Create an adapter that returns buffer strings."""
@@ -437,7 +453,7 @@ def step_have_tracked_file_entity(context: Any, name: str) -> None:
 @when("I track the same entity again")
 def step_track_same_entity(context: Any) -> None:
     """Track the same entity again to update it."""
-    time.sleep(0.01)  # Small delay to ensure time difference
+    _wait_for_clock_advance(datetime.now(UTC))
     context.tracked_entity = context.memory_service.track_entity(
         context.tracked_entity.name, context.tracked_entity.entity_type
     )
@@ -504,11 +520,11 @@ def step_memory_service_entities_over_time(context: Any) -> None:
     """Track entities at different times."""
     context.memory_service = MemoryService(session_id="time-entity-session")
 
-    # Track entities with small delays to ensure different timestamps
+    # Track entities with clock-advance guards to ensure different timestamps
     context.memory_service.track_entity("oldest", EntityType.PROJECT)
-    time.sleep(0.01)
+    _wait_for_clock_advance(datetime.now(UTC))
     context.memory_service.track_entity("middle", EntityType.PLAN)
-    time.sleep(0.01)
+    _wait_for_clock_advance(datetime.now(UTC))
     context.memory_service.track_entity("newest", EntityType.FILE)
 
 
@@ -763,7 +779,7 @@ def step_track_project_with_initial_metadata(context: Any, name: str) -> None:
 @when("I track the same project entity again with additional metadata")
 def step_track_same_entity_with_additional_metadata(context: Any) -> None:
     """Track the same entity with additional metadata to trigger update."""
-    time.sleep(0.01)  # Small delay to ensure time difference
+    _wait_for_clock_advance(datetime.now(UTC))
     additional_metadata = {"status": "active", "priority": "high"}
     context.tracked_entity = context.memory_service.track_entity(
         context.entity_name, EntityType.PROJECT, additional_metadata