diff --git a/internal/api/api.go b/internal/api/api.go
index b2264b8..97fa2ad 100644
--- a/internal/api/api.go
+++ b/internal/api/api.go
@@ -67,7 +67,7 @@ func (a *API) Register(app core.App) {
 		})
 		e.Router.GET("/robots.txt", func(event *core.RequestEvent) error {
 			event.Response.Header().Set("Cache-Control", "no-store")
-			return event.String(http.StatusOK, "User-agent: *\nDisallow:\n")
+			return event.String(http.StatusOK, "User-agent: *\nContent-Signal: search=no, ai-input=no, ai-train=no, use=immediate\nDisallow:\n")
 		})
 		e.Router.POST("/api/payments", a.createPayment).Bind(apis.BodyLimit(maxPaymentRequestBytes))
 		e.Router.GET("/api/payments/{id}", a.getPayment)
diff --git a/internal/api/operations_test.go b/internal/api/operations_test.go
index e51aa1e..663dfe4 100644
--- a/internal/api/operations_test.go
+++ b/internal/api/operations_test.go
@@ -280,7 +280,7 @@ func TestOperatorSPAUsesSecurityHeadersAndRejectsUnknownBrowserRoutes(t *testing
 		}
 	}
 	res, robots := fixture.request(t, http.MethodGet, "/robots.txt", nil, "", false)
-	if res.StatusCode != http.StatusOK || !bytes.Contains(robots, []byte("User-agent: *")) || res.Header.Get("X-Robots-Tag") == "" {
+	if res.StatusCode != http.StatusOK || !bytes.Contains(robots, []byte("User-agent: *")) || !bytes.Contains(robots, []byte("Content-Signal: search=no")) || res.Header.Get("X-Robots-Tag") == "" {
 		t.Fatalf("robots status=%d header=%q body=%s", res.StatusCode, res.Header.Get("X-Robots-Tag"), robots)
 	}
 	for _, path := range []string{"/contact/", "/sitemap.xml"} {