Slice #2: skill checks + humanity / cyberpsychosis

Shipped as 9d72abe.

What Changed

This entry documents the core tabletop-inspired mechanics for checks, humanity, and cyberpsychosis pressure.

Core tabletop mechanics the rest of the engine leans on.

SkillCheck: 1d10 + STAT + SKILL vs DV. CP RED crits — nat 10 adds another d10, nat 1 subtracts one. Opposed checks tie to the defender.

Humanity: ceiling = EMP × 10. Installing chrome rolls humanity loss; effective EMP = floor(humanity/10). Status tracks stable → at_risk → cyberpsychotic. Requirement chains block orphan cyberware options.

Cyberware v0: 8 categories, ~24 entries in data/cyberware.json.

Demo that shows the tradeoff biting:

php bin/chrome-demo.php --seed=1337 --emp=8
# Fully loaded solo ends AT_RISK (EMP 2)

Tests: 24/24 green at this commit.

Why It Matters

The purpose is continuity: future work is easier when the reason, scope, and verification for each slice are recorded next to the code history.

Implementation Notes

The commit message for this slice was:

Core CP RED mechanics that the rest of the engine leans on.

- SkillCheck: 1d10 + STAT+SKILL + mods vs DV, with CP RED crit rules
  (nat 10 -> add another d10; nat 1 -> subtract another d10) and opposed
  checks (tie -> defender). Deterministic via seeded Rng.
- Cyberware v0 JSON: 8 categories (fashion/neural/optics/audio/body/limbs/
  borg/weapons), eddies + humanity-loss dice + requirement chains. Otto v0
  draft to reconcile vs Athena's set + source (#614/#616).
- Humanity: Humanity = EMP*10 ceiling; installing chrome rolls Humanity Loss
  and drops effective EMP (floor(humanity/10)); stable -> at_risk (EMP<=2) ->
  cyberpsychotic (EMP<=0). Requirement gate blocks orphan options.
- Demos: bin/chrome-demo.php. Bootstrap loads cyberware (idempotent).
- Tests now 24/24 green (added skillcheck crit bounds + opposed, humanity
  determinism + monotonic EMP + threshold + requirement gate + cw idempotency).

Refs project #16, doc #345.

Files touched in this slice included:

• bin/chrome-demo.php
• data/cyberware.json
• includes/Humanity.php
• includes/Rules.php
• includes/SkillCheck.php
• tests/run-tests.php

Verification

• The entry is part of the devlog archive and renders through the same PHP Markdown pipeline as current posts.
• The test suite now requires every devlog post to carry substantive details, illustration and screenshot figures, and valid visual asset references.
• Current browser smoke checks cover representative rich posts and older auto-generated posts after expansion.

Visuals