Need help with a tech tree for espionage?

I need help thinking of example tech in the field of espionage for my roleplaying game
Level 0: Stone Age
Level 1: Medieval
Level 2: Industrial Revolution
Level 3: WWII
Level 4: Modern Era
Level 5: Post-modern
Level 6: Future
Level 7: Far Future

None
Inquisitor
Spy
Code breaker
Firewall
Corporate espionage
Espers (psychics)
Hive mind.
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Kinda a mix of both pro and defensive spying

Thanks!!!!

Testing