diff --git a/watchtower/wtwire/error_code.go b/watchtower/wtwire/error_code.go
new file mode 100644
index 000000000..6a441784a
--- /dev/null
+++ b/watchtower/wtwire/error_code.go
@@ -0,0 +1,20 @@
+package wtwire
+
+// ErrorCode represents a generic error code used when replying to watchtower
+// clients. Specific reply messages may extend the ErrorCode primitive and add
+// custom codes, so long as they don't collide with the generic error codes..
+type ErrorCode uint16
+
+const (
+	// CodeOK signals that the request was successfully processed by the
+	// watchtower.
+	CodeOK ErrorCode = 0
+
+	// CodeTemporaryFailure alerts the client that the watchtower is
+	// temporarily unavailable, but that it may try again at a later time.
+	CodeTemporaryFailure ErrorCode = 40
+
+	// CodePermanentFailure alerts the client that the watchtower has
+	// permanently failed, and further communication should be avoided.
+	CodePermanentFailure ErrorCode = 50
+)