diff --git a/quickcheck/aefate_code_eqc.erl b/quickcheck/aefate_code_eqc.erl
index ad66074..fc46c0e 100644
--- a/quickcheck/aefate_code_eqc.erl
+++ b/quickcheck/aefate_code_eqc.erl
@@ -77,7 +77,7 @@ prop_opcodes() ->
 
 
 valid_opcodes() ->
-    lists:seq(0, 16#9a) ++ lists:seq(16#fa, 16#fd).
+    lists:seq(0, 16#9b) ++ lists:seq(16#fa, 16#fd).
 
 
 fate_code(Failure) ->
diff --git a/src/aeb_fate_generate_ops.erl b/src/aeb_fate_generate_ops.erl
index da0e853..36da851 100644
--- a/src/aeb_fate_generate_ops.erl
+++ b/src/aeb_fate_generate_ops.erl
@@ -211,6 +211,7 @@ ops_defs() ->
 
     , { 'AENS_LOOKUP',         16#99,  false, false, true,  100, [a,a],        aens_lookup,  {string}, variant, "Lookup the name of Arg0. Returns option(AENS.name)"}
     , { 'ORACLE_EXPIRY',       16#9a,  false, false, true,  100, [a,a],      oracle_expiry,  {oracle},     int, "Arg0 := expiry block for oracle Arg1"}
+    , { 'AUTH_TX',             16#9b,  false,  true, true,  100,   [a],            auth_tx,        {}, variant, "If in GA authentication context return Some(Tx) otherwise None."}
 
     , { 'DEACTIVATE',          16#fa,  false,    true,   true,   10, [],           deactivate,                                  {},    none, "Mark the current contract for deactivation."}
     , { 'ABORT',               16#fb,   true,    true,   true,   10, [a],               abort,                            {string},    none, "Abort execution (dont use all gas) with error message in Arg0."}