snippet of agi:

$result=$agi->get_var(test);
echo "VERBOSE \"Data: ".$result[data]." \" \n";
echo "VERBOSE \"Result: ".$result[result]." \" \n";
echo "VERBOSE \"Code: ".$result[code]." \" \n";

snippet of dialplan:

exten => 889,1,Answer()
exten => 889,2,Set(test=12345)
exten => 889,3,AGI(savestate.php)

snippet of result:

savestate.php: >> GET VARIABLE test
savestate.php: Data:
savestate.php: Result: 1
savestate.php: Code: 200