yysworld
YYBW-004·Decided·2026-04-13

Branches Arise from Acquisitions and Drift Gradually

depends on YYBW-002, YYBW-003

  • ID: YYBW-004
  • Status: Decided
  • Date: 2026-04-13
  • Scope: YY Branching World / YY's World evolution
  • Depends on: YYBW-002, YYBW-003
  • Supersedes / clarifies: Clarifies branch origin and rejects instant hard divergence
  • Museum lineage: SK-007

Context

The product needed a clean branching logic. Abstract trait mutation and weird parallel selves were initially interesting, but the cleaner form became: same YY, shared root, then a branch where YY acquires a skill, language, or capability. The branch should not become a different being instantly; it should be slightly offset and then drift.

Decision

Primary branches are created by explicit acquisitions or capability changes: e.g. learning to help, negotiation, planning, a second language, or another skill. Post-branch divergence starts subtly and compounds over time.

Why

This makes branches:

  • understandable
  • explainable
  • comparable
  • emotionally believable
  • experimentally useful

Alternatives considered

  1. Pure entropy branches only — kept as an interesting special case, but not the default branch logic.
  2. Immediate binary personality swaps — rejected as unbelievable.
  3. Purely decorative language overlays — rejected in favor of language as a real capability/acquisition source.

Reversals / scars preserved

  • Parallel-world weirdness was useful as a generative phase but too muddy as the default explanatory model.
  • Entropy-only twins remain valuable as diagnostics, but not as the main branch mechanism.
  • The phrase 'same being, slightly offset' became load-bearing.

Consequences

  • Branch metadata must include branch cause and branch day.
  • The diff system must support progressive drift, not just point-in-time flips.
  • The UI should visually show branches staying close early and widening later.

Invariants preserved

Explainability via branch causes; Compression via a simple branching rule; Scars via preserving entropy as a special branch class; Discipline via rejecting arbitrary divergence.

Freshness boundary

Stable unless the branch mechanism broadens materially beyond acquisitions.