diff --git a/internal/permission/config_policy.go b/internal/permission/config_policy.go
index d9b223091..360bb256d 100644
--- a/internal/permission/config_policy.go
+++ b/internal/permission/config_policy.go
@@ -364,7 +364,13 @@ func switchModeEscalates(input json.RawMessage) bool {
 		Mode string `json:"mode"`
 	}
 	_ = json.Unmarshal(input, &a)
-	m := strings.TrimSpace(a.Mode)
+	// #4260: the tool side parses the mode case-INSENSITIVELY
+	// (switch_mode.go lowercases before ParsePermissionMode), and the
+	// permission Check sees the raw JSON args BEFORE CoerceEnumValues
+	// normalizes them. A case-sensitive compare here let {"mode":"Bypass"}
+	// skip the escalation Ask entirely while still switching into bypass -
+	// normalize the same way the parser does.
+	m := strings.ToLower(strings.TrimSpace(a.Mode))
 	return m == "bypass" || m == "autopilot"
 }
 
diff --git a/internal/permission/zz_issue4260_test.go b/internal/permission/zz_issue4260_test.go
new file mode 100644
index 000000000..037716e4e
--- /dev/null
+++ b/internal/permission/zz_issue4260_test.go
@@ -0,0 +1,28 @@
+package permission
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+// #4260: the escalation gate must match the parser's case-insensitive
+// semantics - every casing of bypass/autopilot escalates (Ask), mixed-case
+// non-escalating targets stay Allow.
+func TestIssue4260_EscalationGateCaseInsensitive(t *testing.T) {
+	for _, raw := range []string{
+		`{"mode":"Bypass"}`, `{"mode":"BYPASS"}`, `{"mode":"ByPass"}`,
+		`{"mode":"Autopilot"}`, `{"mode":"AUTOPILOT"}`, `{"mode":"autopilot"}`,
+		`{"mode":"  bypass  "}`,
+	} {
+		if !switchModeEscalates(json.RawMessage(raw)) {
+			t.Fatalf("%s must escalate (Ask gate), got false - privilege-bypass regression", raw)
+		}
+	}
+	for _, raw := range []string{
+		`{"mode":"supervised"}`, `{"mode":"Supervised"}`, `{"mode":"auto"}`, `{"mode":"Auto"}`, `{"mode":"plan"}`,
+	} {
+		if switchModeEscalates(json.RawMessage(raw)) {
+			t.Fatalf("%s must NOT escalate, got true", raw)
+		}
+	}
+}