diff --git a/fleetd/src/test/java/dev/ltms/fleet/config/FleetConfigTest.java b/fleetd/src/test/java/dev/ltms/fleet/config/FleetConfigTest.java
index 47e93b22..11002d31 100644
--- a/fleetd/src/test/java/dev/ltms/fleet/config/FleetConfigTest.java
+++ b/fleetd/src/test/java/dev/ltms/fleet/config/FleetConfigTest.java
@@ -800,6 +800,33 @@ class FleetConfigTest {
         assertTrue(e.getMessage().contains("sonnet"), "the message must name the other offending lead");
     }
 
+    /**
+     * fleetd #693: the guard matches tabs case-insensitively, because
+     * {@code LeadTabScanner} keys its tab map on a lowercased label — two tabs differing only in
+     * case collide there too, and the guard must catch that independently of the exact-match case
+     * above.
+     */
+    @Test
+    void twoLeadsSharingTheSameTabInDifferentCaseRefusesToStart(@TempDir Path dir) throws Exception {
+        Path f = dir.resolve("shared-tab-case.yaml");
+        Files.writeString(f, """
+                bind:
+                  port: 8080
+                fleet:
+                  leaders:
+                    opus:
+                      tab: "Shared Tab"
+                    sonnet:
+                      tab: "shared tab"
+                """);
+        FleetConfig cfg = FleetConfig.load(f);
+
+        IllegalStateException e =
+                assertThrows(IllegalStateException.class, cfg::validateLeadTabPrefixes);
+        assertTrue(e.getMessage().contains("opus"), "the message must name one offending lead");
+        assertTrue(e.getMessage().contains("sonnet"), "the message must name the other offending lead");
+    }
+
     /** Control for {@link #twoLeadsSharingTheSameExactTabRefusesToStart}: distinct tabs load cleanly. */
     @Test
     void twoLeadsWithDistinctExactTabsAreAllowed(@TempDir Path dir) throws Exception {
diff --git a/fleetd/src/test/java/dev/ltms/fleet/config/FleetConfigValidateAllTest.java b/fleetd/src/test/java/dev/ltms/fleet/config/FleetConfigValidateAllTest.java
index eb4b0e54..cdaa108c 100644
--- a/fleetd/src/test/java/dev/ltms/fleet/config/FleetConfigValidateAllTest.java
+++ b/fleetd/src/test/java/dev/ltms/fleet/config/FleetConfigValidateAllTest.java
@@ -19,7 +19,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 /**
  * Tests the reflective validator sweep and {@link FleetConfig#validateAll()} reachability.
  *
- * <p>{@link #theSweepMechanismIsGenericNotHardcodedToFleetConfigsSixNames()} and its neighbours
+ * <p>{@link #theSweepRunsEveryValidateMethodOnAnUnrelatedClass()} and its neighbours
  * prove that {@link FleetConfig#invokeAllValidators} runs each public, no-arg, void
  * {@code validateXxx()} method on its target. {@link #fleetConfigDeclaresExactlyTheseValidatorsToday()}
  * is the canary for the validator set. {@link #validateAllReachesEveryOneOfTodaysRealValidators()}
@@ -50,7 +50,7 @@ class FleetConfigValidateAllTest {
     }
 
     @Test
-    void theSweepMechanismIsGenericNotHardcodedToFleetConfigsSixNames() {
+    void theSweepRunsEveryValidateMethodOnAnUnrelatedClass() {
         ThreeValidators target = new ThreeValidators();
         FleetConfig.invokeAllValidators(target);
         assertEquals(List.of("validateAlpha", "validateBeta", "validateGamma"), target.ran,