diff --git a/internal/cmd/done.go b/internal/cmd/done.go
index a385ac07..4fd24a35 100644
--- a/internal/cmd/done.go
+++ b/internal/cmd/done.go
@@ -82,6 +82,14 @@ func init() {
 }
 
 func runDone(cmd *cobra.Command, args []string) error {
+	// Guard: Only polecats should call gt done
+	// Crew, deacons, witnesses etc. don't use gt done - they persist across tasks.
+	// Polecats are ephemeral workers that self-destruct after completing work.
+	actor := os.Getenv("BD_ACTOR")
+	if actor != "" && !isPolecatActor(actor) {
+		return fmt.Errorf("gt done is for polecats only (you are %s)\nPolecats are ephemeral workers that self-destruct after completing work.\nOther roles persist across tasks and don't use gt done.", actor)
+	}
+
 	// Handle --phase-complete flag (overrides --status)
 	var exitType string
 	if donePhaseComplete {
@@ -708,6 +716,14 @@ func selfNukePolecat(roleInfo RoleInfo, _ string) error {
 	return nil
 }
 
+// isPolecatActor checks if a BD_ACTOR value represents a polecat.
+// Polecat actors have format: rigname/polecats/polecatname
+// Non-polecat actors have formats like: gastown/crew/name, rigname/witness, etc.
+func isPolecatActor(actor string) bool {
+	parts := strings.Split(actor, "/")
+	return len(parts) >= 2 && parts[1] == "polecats"
+}
+
 // selfKillSession terminates the polecat's own tmux session after logging the event.
 // This completes the self-cleaning model: "done means gone" - both worktree and session.
 //
diff --git a/internal/cmd/done_test.go b/internal/cmd/done_test.go
index 26272387..1166377a 100644
--- a/internal/cmd/done_test.go
+++ b/internal/cmd/done_test.go
@@ -341,3 +341,39 @@ func TestGetIssueFromAgentHook(t *testing.T) {
 		})
 	}
 }
+
+// TestIsPolecatActor verifies that isPolecatActor correctly identifies
+// polecat actors vs other roles based on the BD_ACTOR format.
+func TestIsPolecatActor(t *testing.T) {
+	tests := []struct {
+		actor string
+		want  bool
+	}{
+		// Polecats: rigname/polecats/polecatname
+		{"testrig/polecats/furiosa", true},
+		{"testrig/polecats/nux", true},
+		{"myrig/polecats/witness", true}, // even if named "witness", still a polecat
+
+		// Non-polecats
+		{"gastown/crew/george", false},
+		{"gastown/crew/max", false},
+		{"testrig/witness", false},
+		{"testrig/deacon", false},
+		{"testrig/mayor", false},
+		{"gastown/refinery", false},
+
+		// Edge cases
+		{"", false},
+		{"single", false},
+		{"polecats/name", false}, // needs rig prefix
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.actor, func(t *testing.T) {
+			got := isPolecatActor(tt.actor)
+			if got != tt.want {
+				t.Errorf("isPolecatActor(%q) = %v, want %v", tt.actor, got, tt.want)
+			}
+		})
+	}
+}