I Tore Apart the Claude Code Source Code 3/3

More posts at radarlog.kr . The most surprising thing I found digging through Claude Code's source wasn't a tool or an architecture pattern. It was opening the buddy/ folder. There's a virtual pet system. It works like a gacha game. Five rarity tiers. Eighteen species. Buddy — A Gacha Virtual Pet Inside a Coding Agent src/buddy/ directory. Five files, 79KB. Gated behind the BUDDY feature flag, so it's not publicly available yet. But the implementation is complete. Characters are generated deterministically from the userId as a seed. Same user always gets the same character. The PRNG is Mulberry32 . function mulberry32 ( seed : number ): () => number { let a = seed >>> 0 return function () { a |= 0 a = ( a + 0x6d2b79f5 ) | 0 let t = Math . imul ( a ^ ( a >>> 15 ), 1 | a ) t = ( t + Math . imul ( t ^ ( t >>> 7 ), 61 | t )) ^ t return (( t ^ ( t >>> 14 )) >>> 0 ) / 4294967296 } } As a game developer, I recognize this instantly. Lightweight seeded random. Mulberry32 is commonly used in gam