diff --git a/summarize_test_results.py b/summarize_test_results.py
index 2a1bc4a..21edfd6 100644
--- a/summarize_test_results.py
+++ b/summarize_test_results.py
@@ -589,20 +589,29 @@ def compute_semaphore(success_percent, embed=True):
     If set to `embed`, an emoji will be used. Else, a textual representation
     of a Slack emoji is used.
     """
-    if embed:
-        if success_percent >= 95:
-            return "🟢"
-        elif success_percent >= 60:
-            return "🟡"
-        else:
-            return "🔴"
+    levels = {
+        "good": {
+            "emoji": "🟢",
+            "text": ":large_green_circle:",
+        },
+        "average": {
+            "emoji": "🟡",
+            "text": ":large_yellow_circle:",
+        },
+        "bad": {
+            "emoji": "🔴",
+            "text": ":red_circle:",
+        },
+    }
+    form = "emoji"
+    if not embed:
+        form = "text"
+    if success_percent >= 99:
+        return levels["good"][form]
+    elif success_percent >= 95:
+        return levels["average"][form]
     else:
-        if success_percent >= 95:
-            return ":large_green_circle:"
-        elif success_percent >= 60:
-            return ":large_yellow_circle:"
-        else:
-            return ":red_circle:"
+        return levels["bad"][form]
 
 
 def compute_thermometer_on_metric(summary, metric, embed=True):
diff --git a/test_summary.py b/test_summary.py
index 128dbd3..5ad5f2e 100644
--- a/test_summary.py
+++ b/test_summary.py
@@ -69,19 +69,35 @@ def test_compute_summary(self):
 
     def test_compute_thermometer(self):
         self.maxDiff = None
-        thermometer = summarize_test_results.compute_thermometer_on_metric(self.summary, "by_platform")
+        thermometer = summarize_test_results.compute_thermometer_on_metric(
+            self.summary, "by_platform"
+        )
 
         self.assertEqual(
             thermometer,
             "Platforms thermometer:\n\n"
-            "- 🟡 - local: 66.7% success.\t(1 out of 3 tests failed)\n\n"
+            "- 🔴 - local: 66.7% success.\t(1 out of 3 tests failed)\n\n",
+        )
+
+        thermometerPlaintext = summarize_test_results.compute_thermometer_on_metric(
+            self.summary, "by_platform", False
+        )
+
+        self.assertEqual(
+            thermometerPlaintext,
+            "Platforms thermometer:\n\n"
+            "- :red_circle: - local: 66.7% success.\t(1 out of 3 tests failed)\n\n",
         )
 
     def test_compute_systematic_failures(self):
         self.maxDiff = None
 
         for metric in ["by_test", "by_k8s", "by_postgres", "by_platform"]:
-            has_alerts, out = summarize_test_results.compute_systematic_failures_on_metric(self.summary, metric)
+            has_alerts, out = (
+                summarize_test_results.compute_systematic_failures_on_metric(
+                    self.summary, metric
+                )
+            )
             self.assertEqual(has_alerts, False)
             self.assertEqual(out, "")