dota_factory/docs/balancing/history.md

# Balancing History

Chronological record of the balancing work: what was decided, what was
found, what changed. Current values live in `derived.md`; this file
explains how they got there.

## 2026-07-02/03 — rules and structural decisions

- Rules document written (now `rules.md`): ratio curve, shortcut
  recipes, refactorability, cost archetypes, threat model, growth curve.
- Scrap derived from threat (`scrap_per_threat`), replacing authored
  per-ship scrap drops; scrap threat became the constant
  `1/scrap_per_threat`, removing the old min-scrap_drop derivation and
  its circularity.
- Duplicate schematic drops removed (no level-ups); ship/module levels
  removed entirely — all time scaling lives in the threat rate, push
  scaling stays on stations. Mk2 upgrade recipes noted as the future
  per-item progression.
- Growth-curve rules added: escalating expansion costs, designed
  doubling time, growth limited by economy not waiting; resource
  deposits designed (deposit-gated mid resource in expansion territory).
- Production tree v2 decided: iron/copper everywhere (M-type asteroid),
  quartz in geodes (mid), voidsteel battle-forged from scrap (late);
  titanium dropped; lasers renamed to railguns, lasers reserved as a
  future weapon type.

## 2026-07-03 — targets, tree, numbers

- Balancing targets fixed: ≤2 h run, phases 1–5/6–14/15+, factory curve
  25/60/120/150, threat ladder, 25-ship swarm, block roots.
- Tree structure drafted and numbers computed (recursive threat
  calculator); ratio curve realized; fitted ships within 96–124% of the
  strawman ladder (small end hot from fixed chain overhead — ladder
  later adopted the achieved values).
- **Rule bugs found by the numbers work:** the scrap→ingot smelter
  recipe would inflate basic materials via the max rule (fixed:
  scrap-consuming recipes are threat fallback only); recipe output
  amounts were ignored (fixed: per-unit division); items downstream of
  reprocessing-only items never resolved (fixed: fixpoint resolution);
  a shortcut recipe resolving earlier than the base path silently
  underpriced items (fixed: commit only when all eligible recipes are
  computable). All four fixed in `ThreatCostCalculator` with tests, and
  implemented in `tools/threat_report.py`.
- v2 tree written into the configs; `default_modules` loadouts
  geometry-validated (the numbers-pass loadouts for battlecruiser and
  dreadnought were geometrically impossible — L-modifiers don't fit
  beside full gun complements; corrected loadouts landed closer to the
  ladder).

## 2026-07-04 — combat stats, arena rounds 1–5

Initial stats derived from the anchors (weapon DPS ≈0.6/threat flat,
hull 15 HP/threat, armor 20/threat, repair 2 HP/s/threat, station
range 200).

- **Round 1:** concentrated fleets won all equal-threat cross-tier
  matchups flawlessly; glass beat armored; repair escort flawless; two
  stations shrugged off a 3× swarm. Changes: concentration tax on m/l
  gun damage (railgun_m 17→14, railgun_l 70→52), armor 640→1000,
  repair 25→12, station range 200→120. (Team-1 "bias" in mirrors later
  shown to be noise.)
- **Round 2 (EHP-margin logging added):** battleship +33% while
  dreadnought −37% (stabilizer range + opposing armor); glass still
  +11%. Changes: stabilizer range ×1.5→×1.3; per-hull trims introduced
  (BC 2700→2500, BS 7500→7000, DN/CV 15500→19000).
- **Round 3 (narrow lanes — geometry fixed into the fixture):**
  DN closed to −11%, BS +22%, swarm flipped to +14% over cruisers,
  glass +12% third time. Changes: armor 1000→1200, BC 2500→2000,
  BS 7000→6300, DN/CV 19000→22500.
- **Round 4:** glass-vs-armored resolved (+3% armored); noise floor
  established (~±10%/run: BS ignored a −10% EHP cut; repair drifted
  14→24% untouched). Convergence policy adopted: two-round signals only,
  ±20% converged. Changes: BC 2000→2200, DN/CV 22500→24000; BS +23%
  accepted as doctrine texture (mechanical range edge vs. pure small
  fleets).
- **Round 5 (durations logged; end-condition bug fixed upstream):**
  TTK anchor validated (mirrors 23/71/95 s; DN-vs-swarm 214 s outlier
  accepted); dreadnought +3%, everything else inside band. Final
  changes: BC 2200→2400, repair 12→9 (persistent +24% escort margin).
  **Combat pass declared converged.**

## 2026-07-05/06 — pacing pass

- Unlock ladder set (starting set drone/frigate/railgun_s/salvager;
  quartz gate at level 2; capitals at 8–9 with `unlock_requires`
  chains); threat rate `2*x + 0.15*x*x`; starting blocks 1000→200;
  expansion 400 flat pending the cost formula; artifacts 3→5.
- **Bug found:** the building_block recipe was silently locked at game
  start (building blocks appear in no schematic's materials, so implicit
  unlocking could never reach the recipe) — fixed with an explicit
  `unlock_at_station_level = -1`.
- Expansion cost formula implemented and set (`300 + 50*x + 10*x*x`):
  quadratic, so costs outrun the roughly linear block income gradually
  — ~1 expansion per cycle mid-game, 2–3 cycles apart late.
- **First full balancing round complete.** Next: full-game playtests
  against the run-shape targets.

## 2026-07-06 — playtest 1 (first two pushes)

First real run: two enemy stations destroyed in ~40 min game time
(~80 min real time with heavy build-pausing) — roughly on pace for the
≤2 h game-time target, so pacing untouched.

- **Meta finding: cruisers filled with 12× railgun_s dominate.** Predicted
  by the numbers in hindsight: the concentration tax makes railgun_s the
  best DPS/threat (0.62 vs m 0.48, l 0.41), range is the big guns' only
  mechanical edge (armor is added HP, not damage reduction — no anti-swarm
  mechanic), repair sustain covers the closing distance, and stations
  outranged every ship gun (120 vs railgun_l's 100), so even capitals had
  to tank-and-brawl. The cruiser compounds it: first hull with a large
  1×1 canvas (12 cells) and a nearly quartz-free chain.
- **Repair tool confirmed overpowered** (second signal after the
  persistent +24% arena escort margin): the arena only prices in-fight
  sustain; real runs add free full top-offs in every 15–45 s wave gap
  across the whole swarm. The 0.7 HP/s-per-threat prior is wrong for
  wave defence.
- **Changes:** repair_tool 9→4 HP/s; railgun_l range 100→130 (now
  outranges stations — buys the siege role the capital ladder promises);
  railgun_m 14→16 dmg and range 70→80 (tax softened: m sits at 0.55
  DPS/threat, between s and l). Module threats unchanged (costs
  untouched), so no ladder recalculation needed.
- New tracked arena added: railgun_s-spam cruisers (8× 178) vs default
  cruisers (6× 233.5) — the spam side should win a brawl somewhat, but a
  blowout means the small-gun premium needs retuning.
- **Open:** re-run the arena suite to check the range/damage changes
  against the round 1–5 results; next playtest should verify big guns now
  feel worth climbing to and repair is merely good.