diff --git a/models/Agent.json b/models/Agent.json
index 045f5c7..90c19ed 100644
--- a/models/Agent.json
+++ b/models/Agent.json
@@ -17,6 +17,7 @@
     },
     "credits": {
       "type": "integer",
+      "format": "int64",
       "description": "The number of credits the agent has available. Credits can be negative if funds have been overdrawn."
     },
     "startingFaction": {
@@ -32,4 +33,4 @@
     "credits",
     "startingFaction"
   ]
-}
\ No newline at end of file
+}
diff --git a/reference/SpaceTraders.json b/reference/SpaceTraders.json
index b7b5390..5d46970 100644
--- a/reference/SpaceTraders.json
+++ b/reference/SpaceTraders.json
@@ -119,7 +119,8 @@
                                 "type": "string"
                               },
                               "credits": {
-                                "type": "integer"
+                                "type": "integer",
+                                "format": "int64"
                               }
                             },
                             "required": [
@@ -2816,4 +2817,4 @@
       }
     }
   }
-}
\ No newline at end of file
+}