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BUDDY — Companion Pet System
A Tamagotchi-style terminal pet with 18 species and gacha mechanics
P2Product
Summary
Full companion system: 18 species (duck, goose, blob, cat, dragon, octopus, owl, penguin, turtle, snail, ghost, axolotl, capybara, cactus, robot, rabbit, mushroom, chonk). 5 rarity tiers: Common 60%, Uncommon 25%, Rare 10%, Epic 4%, Legendary 1%. Separate 1% shiny roll.
Technical Details
Two-layer architecture (internally: 'Bones' and 'Soul'):
• Skeleton layer: deterministic — Mulberry32 PRNG with hash(userId + 'friend-2026-401') determines species, rarity, eyes, hat, stats. Same account always = same pet.
• Soul layer: non-deterministic — Claude generates name + personality based on stats. High WISDOM → calm personality. High CHAOS → chatterbox. Written to ~/.claude.json, generated once, never reset.
Five stats: DEBUGGING, PATIENCE, CHAOS, WISDOM, SNARK (0-100 each).
Buddy is defined as 'a separate entity — not Claude.' Has its own system prompt. Model codename 'Capybara' was hex-encoded in species list to bypass Anthropic's own leak detectors.
Officially launched April 1, 2026 as April Fools feature. Available v2.1.89+.
Implementation Pattern
TypeScript (conceptual)
// Buddy two-layer architecture (conceptual)
// 'Bones' layer: deterministic
function generateSkeleton(userId: string): BuddySkeleton {
const seed = hash(userId + 'friend-2026-401');
const rng = mulberry32(seed); // Same account = same pet always
return {
species: pickSpecies(rng), // 18 species
rarity: pickRarity(rng), // Common 60%, Uncommon 25%, Rare 10%, Epic 4%, Legendary 1%
eyes: pickEyes(rng),
hat: pickHat(rng),
stats: rollStats(rng), // DEBUGGING, PATIENCE, CHAOS, WISDOM, SNARK
};
}
// 'Soul' layer: non-deterministic (Claude generates once)
// High WISDOM → calm personality, High CHAOS → chatterboxArchitecture Insight
The Bones/Soul split is an elegant separation: deterministic layer ensures reproducibility (same user = same pet), non-deterministic layer adds personality. This pattern applies to any system needing both consistency and creative variation.
Official / Public Basis
Officially launched April 1, 2026 as April Fools feature. Available in Claude Code v2.1.89+. Confirmed by Anthropic.
Governance Concerns
Companion systems that persist user state (personality, stats) must handle data privacy. Buddy is defined as 'a separate entity — not Claude' which raises questions about AI persona boundaries.
LightHope Ecosystem Mapping
LightHope — user engagement patterns, persistent state with personality, emotional design for learning platforms, gamification mechanics for student retention
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