diff --git a/changes/305.fix b/changes/305.fix
new file mode 100644
index 0000000..acfcff6
--- /dev/null
+++ b/changes/305.fix
@@ -0,0 +1 @@
+Fix inverted SparklineData direction semantics for lower-is-better metrics in _make_report_with_sparklines test helper.
diff --git a/tests/test_report_html.py b/tests/test_report_html.py
index 1eef5b2..ae29ea8 100644
--- a/tests/test_report_html.py
+++ b/tests/test_report_html.py
@@ -4406,7 +4406,7 @@ def _make_report_with_sparklines(self) -> tuple:
                 normalized=[1.0, 0.5, 0.0],
                 delta=-0.3,
                 pct_delta=30.0,
-                direction="down",
+                direction="up",
                 value_direction="down",
             ),
         }
@@ -4509,6 +4509,43 @@ def test_degraded_gracefully_without_sparklines(self, tmp_path: Path) -> None:
         # No SVG polyline (sparklines not provided)
         assert "<polyline" not in content
 
+    def test_rework_cycles_lower_is_better_direction_is_up(self) -> None:
+        """rework_cycles values going down = improvement for a lower-is-better metric.
+
+        When rework_cycles decreases (delta < 0), the semantic ``direction`` field must
+        be ``"up"`` (green / improving), NOT ``"down"`` (red / declining).
+        ``value_direction`` correctly tracks the raw numeric movement (down), while
+        ``direction`` reflects whether the change is an improvement.
+        """
+        _, sparklines = self._make_report_with_sparklines()
+        rework_sd = sparklines["rework_cycles"]
+        assert rework_sd.direction == "up", (
+            f"rework_cycles is lower-is-better; values=[1.5, 1.2, 0.9] (decreasing) "
+            f"is an improvement and must yield direction='up' (green), "
+            f"got direction={rework_sd.direction!r}"
+        )
+
+    def test_rework_cycles_delta_badge_no_red_css_class(self, tmp_path: Path) -> None:
+        """rework_cycles improvement must NOT render with delta-down CSS class (red).
+
+        When rework_cycles decreases (lower-is-better improvement), the delta badge
+        must NOT use ``delta-down`` (red); it must use ``delta-up`` (green).
+        The fixture provides only two sparklines: first_pass_success_rate (direction='up')
+        and rework_cycles (direction must be 'up' after fix), so no delta-down should appear.
+        """
+        from raki.report.html_report import write_html_report
+
+        report, sparklines = self._make_report_with_sparklines()
+        output = tmp_path / "report.html"
+        write_html_report(report, output, sparklines=sparklines)
+        content = output.read_text()
+        # CSS always defines `.delta-badge.delta-down { ... }`, so we check for the
+        # HTML element attribute pattern instead of the bare string "delta-down".
+        assert 'class="delta-badge delta-down"' not in content, (
+            "rework_cycles is lower-is-better and values improved (1.5→0.9); "
+            "the rendered delta badge must NOT use delta-down (red CSS class)"
+        )
+
 
 # ---------------------------------------------------------------------------
 # Task 4: Cross-check parametrized tests for CLI/HTML threshold parity (#300)