diff --git a/rest/python/server/routes/discovery_profile.json b/rest/python/server/routes/discovery_profile.json
index af55c47..de6ea4c 100644
--- a/rest/python/server/routes/discovery_profile.json
+++ b/rest/python/server/routes/discovery_profile.json
@@ -106,6 +106,22 @@
             }
           ]
         }
+      },
+      {
+        "id": "mock_payment_handler",
+        "name": "dev.ucp.mock_payment",
+        "version": "2026-01-11",
+        "spec": "https://ucp.dev/specs/mock",
+        "config_schema": "https://ucp.dev/schemas/mock.json",
+        "instrument_schemas": [
+          "https://ucp.dev/schemas/shopping/types/card_payment_instrument.json"
+        ],
+        "config": {
+          "supported_tokens": [
+            "success_token",
+            "fail_token"
+          ]
+        }
       }
     ]
   }