Because Axe source code is compiled into the same assembly language as a "normal" assembly program, there is no surefire way to determine the origins of an assembly program. However, you can make a very accurate educated guess by looking at the disassembled code. Here are a few differences I can think of that should be fairly noticeable between a "normal" assembly program and one generated by Axe:

• Axe programs have a strong foundation in the hl register. A very high amount of h/l usage (and also a very low amount of b/c usage) should hint to a program compiled by Axe parser. This is probably the strongest indicator.
• Axe programs also rely on storage of values in memory, often in the range from saveSScreen+714 to saveSScreen+767. Values are only carried from block to block in either memory or hl. (Or on the stack for subroutines)
• Axe programs will have a lot of conditional branches following the format ld a,h \ or l \ jp (n)z,$XXXX. Very rarely will you see a conditional absolute jump that does not follow the above format or does not use the z flag.