To give you useful guidance, I'll need a bit more detail. Sleeping Dogs (2012, United Front Games/Square Enix) has a limited but dedicated modding community, mostly using file replacements, .dat / .tag editing, and script patches (Lua/XML). No official mod tools exist.
Just let me know the exact feature, and I'll provide a detailed development guide. mod sleeping dogs
I understand you're asking about modding Sleeping Dogs — likely requesting help developing a mod or new feature for the game. To give you useful guidance, I'll need a bit more detail