Hidden pet system discovered in Claude Code leak: gacha mechanics with ASCII animations

Analysis of the leaked Claude Code source reveals a hidden companion pet system that was apparently scheduled for release. The system implements gacha mechanics with deterministic generation based on user IDs.

System architecture

The pet system is located in the buddy/ directory. Companions are deterministically rolled from a hash of the user ID through a seeded PRNG, ensuring the same account always gets the same pet. Species, eyes, hats, rarity, and stats are never stored — they're regenerated every time from the hash. Only the "soul" (name and personality, generated by the model on first hatch) gets persisted to config.

Pet mechanics

• 18 species including duck, ghost, axolotl, capybara, robot, and something called "chonk"
• Rarity weights: common 60%, uncommon 25%, rare 10%, epic 4%, legendary 1%
• 1% shiny chance on top of rarity (legendary shiny is about 1 in 10,000)
• 5 stats per companion: DEBUGGING, PATIENCE, CHAOS, WISDOM, SNARK
• Each species has 3-frame ASCII idle animations with fidget cycles and blinking
• Hats only appear on uncommon+ pets (options include crown, tophat, wizard, and "tinyduck")

Commands and implementation details

The system includes a /buddy pet command that spawns floating hearts. Species names are encoded as hex char codes in the source because one species name collides with an internal model codename. A comment in the code states: "One species name collides with a model-codename canary in excluded-strings.txt."

The teaser was apparently scheduled to go live April 1-7 with a rainbow /buddy notification, then remain permanent.

Specific user ID results

Analysis of brute-forced user IDs reveals specific combinations:

• Typing "ak" gives a legendary robot with a tophat
• Typing "szq" gives a legendary shiny cat
• Typing "bd" gives a legendary blob