reactor-core-lib

Shared reactor simulation engine for Reactor Revival and related games. Hosts own UI, input, and presentation; this package owns sim state, economy debit/credit for game actions, modifiers, and tick phases.

Install

npm install reactor-core-lib decimal.js

decimal.js is required for revival (and any host using Decimal economy). Load it onto globalThis.Decimal before creating a session:

import Decimal from 'decimal.js';
globalThis.Decimal = Decimal;

Without that, toDecimal falls back to Number and revival economy calls like money.add will throw.

Quick start

import { createGameSession } from 'reactor-core-lib';

const session = await createGameSession({ gameId: 'reactor_revival' });
session.tick();
session.dispatch({ type: 'PLACE_PART_PAID', payload: { row: 0, col: 0, id: 'uranium1' } });

Supported GAME_IDS: reactor_revival, reactor_incremental, reactor_knockoff, ic2_reactor_planner_v3, ic2_exp_reactor_planner.

Host cutover guide (1.2.7)

Use these APIs so the host stops reimplementing cost math, sell refunds, modifier key mapping, and upgrade catalog shaping.

Paid placement (one dispatch)

Problem: Hosts debit money/EP, then place, then refund if place fails — easy to desync with partCostForCell. Occupied/OOB coordinates must not debit.

Use: Atomic place+charge:

session.dispatch({
  type: 'PLACE_PART',
  payload: { row, col, id, paid: true },
});
// or
session.dispatch({ type: 'PLACE_PART_PAID', payload: { row, col, id } });
// or
const result = session.placeComponentPaid(row, col, id);
// { ok, cost: { money, ep }, reason?, id, row, col }
// reason: 'bounds' | 'occupied' | 'funds' | 'unknown' | 'place_failed' | ...

Validates bounds and occupancy before debit (no money lost on bad coords). Debit uses partCostForCell; refunds on place failure. Free place remains PLACE_PART without paid / session.placeComponent (may overwrite).

Live part sell (life / containment)

Problem: Host calculateSellValue credits remaining cell life or containment heat damage. Core used to hardcode floor(baseCost * level * 0.5); the revival bridge patched the money delta after SELL_PART.

Use:

session.dispatch({ type: 'SELL_PART', payload: { row, col } });
// authoritative tooltip / HUD preview (uses inst.ticks / def.baseTicks incl. fractional isotope max)
session.computeSellValue(row, col);
computeInstanceSellValue(inst, { row, col, grid });

Do not use host part.ticks (display life) as the sell denominator — that drifts from core fractional baseTicks.

Policy (matches host):

• Cells with ticks: ceil(cost * min(1, max(0, ticksRemaining / maxTicks)))
• Containment parts: cost - ceil(cost * min(1, heatContained / containment))
• Else full cost (def.cost ?? def.baseCost)
• Custom sellValuePolicy / computeSellValue returning non-finite values credits 0

Isotope Stabilization keeps fractional baseTicks on the def (e.g. 15.75) for sell life ratios; placement/runtime ticks use Math.floor(baseTicks).

Override with session.sellValuePolicy = (inst, ctx) => number or payload policy.computeSellValue.

Sell-credit preview + blueprint sell

Flat 0.5× (default): matches APPLY_BLUEPRINT when sellExisting is set without instance options.

const { total, items, sellMultiplier } = session.computeGridSellCredit();
session.dispatch({
  type: 'APPLY_BLUEPRINT',
  payload: { layout, sellExisting: true, sellCredit: total },
});

Instance / life-ratio mode: preview and execution must use the same mode. APPLY_BLUEPRINT with sellExisting pre-flights affordability using absolute layout cost vs money + computeGridSellCredit(...) before any sell; on { ok:false, reason:'deficit' } the grid and wallet are unchanged. With sellExisting, preflight always uses the real sell proceeds (payload sellCredit is not required; host may leave it 0). After a successful preflight sell, apply uses sellCredit: 0 because proceeds are already in the economy.

const credit = session.computeGridSellCredit(0.5, { mode: 'instance' });
session.dispatch({
  type: 'APPLY_BLUEPRINT',
  payload: {
    layout,
    sellExisting: true,
    sellMode: 'instance', // or lifeRatio: true
    sellCredit: credit.total,
  },
});

sellAllComponents(session, mult, { mode: 'instance' }) uses the same policy as SELL_PART.

Paid placement coords

placeComponent / placeComponentPaid / SELL_PART require finite integer in-range coords (isValidGridCoord). Malformed values (NaN, undefined, 0.5) return { ok:false, reason:'bounds' } (paid) or false (free/sell) with no economy mutation. Grid getters never throw on bad coords.

Cell basePower (dual / quad)

Problem: Multi-cell entries used to bake scaled basePower (e.g. uranium2=2.5) while the host keeps template base_power with cellMultiplier 4/12.

Lib: Revival parts.json now stores the single-cell coefficient on all forms (uranium1/2/3 → basePower: 1). Pulse math remains basePower * (cellMultiplier + neighborN).

Honor host effective power/heat (transitional)

Prefer core coeffs: resolveCellCoefficients + pulse. Mid-session display/test mutations without re-placing should set numeric inst.power / inst.heat (layout overrides, same shape as former _effective*).

honorHostEffective + inst._effectivePower / _effectiveHeat still work when the flag is set; drop the bridge once host tests use inst.power/inst.heat or core defs alone.

Purchasing upgrades rebinds placed instances to recompiled defs (reinforcement, isotope ticks, cell power, etc.).

Component reinforcement

component_reinforcement is wired in REVIVAL_EFFECTS / effect-registry (+10% containment per level). Applied when building capacitor / coolant containment and plating reactorHeat. Recompile refreshes placed defs so explosion thresholds and caps update without host _effectiveContainment.

Auto-sell / auto-buy operators

Revival upgrades.json includes auto_sell_operator / auto_buy_operator. Purchase enables mechanicsOverrides.autoSellFromUpgrade / autoBuyFromUpgrade, which OR with toggles.auto_sell / toggles.auto_buy so the host can drop a !hasCoreDef spend path.

Prestige / achievements

Prefer core ownership for weave + reboot — call session.prestige() (or session.reboot) as the sole reboot owner and drop parallel host applyDefaults / clearState:

session.previewPrestige(); // { earned, weaveQuantum, keepEp, fuelCellCount, ... }
session.calculatePrestigeReward();
session.prestige(); // reboot({ keepEp: true, refundEp: false }): clears grid, keeps EP upgrades, resets money upgrades / failure / objectives
session.reboot({ keepEp: true }); // same keep-EP path
session.reboot({ refundEp: true }); // full reset: clears all upgrades

calculateWeaveEp(power, heat, weaveQuantum) is exported for UI without a session. Revival economy.weaveQuantum defaults to manifest.economy.weaveQuantum (1e6).

prestigeCompleted is emitted by core when keepEp === true. Hosts that still run a parallel reset must emit the same payload themselves.

• Prestige achievements unlock only when keepEp === true.
• criticality_recovery_auto aborts when soldHeatCount increases during recovery (full vent / remaining ≤ ε), including after a prior full vent before criticality. A full VENT_HEAT (ventHeat + soldHeat pair) counts once.
• Achievement serialize() persists { unlocked, trackers, sustained, soldHeatCount, lastSnapshot } (array form still deserializes as unlocked-only).
• Events: achievementUnlocked (camelCase, canonical) and ACHIEVEMENT_UNLOCKED alias; tick result includes unlockedAchievementIds.

Compiled part catalog (shop / tooltips)

Prefer core compiled defs over host part.recalculate_stats multiplier walks:

session.listParts(); // post-recompile containment / reactorPower / baseTicks / vent / …
session.getPart('capacitor2');

listUpgrades() part refs include the same compiled fields when session.registry is present.

Catalog parity (1.2.7+): compiled defs match host display for:

• improved_heat_vents / improved_heat_exchangers: +100%/level rate and capacity (vent_boost / transfer_boost)
• improved_reflector_density: doubles reflector baseTicks via reflectorDurationMultiplier
• improved_neutron_reflection: +1%/level on powerIncrease; full_spectrum_reflectors: +100% of base powerIncrease per level
• Experimental: fluid_hyperdynamics, fractal_piping, ultracryonics (coolant ×2^n)
• Cell _cell_power: basePower baked as ×2^level in getPart / listParts (and runtime defs)
• Plating reactorHeat: unfloored base × platingCapacity × (1+platingHeatBonus) × (1+reinforcement) for ceramic_composite shop parity
• PA epHeat: resolveEpHeat / session.resolveEpHeat / catalog epHeat — base × (IPA_level+1) × EP scale × (1−catalyst); tick EP chance uses the same scaled threshold

Drop host-local multiplier walks for these. infused_cells / unleashed_cells remain global cell powerMultiplier / heatMultiplier (knockoff-style), not reflector/transfer overlays from the upgrade blurb.

PA epHeat scale (host deriveEpHeat parity):

• EP scale = 1 + log10(EP / weaveQuantum) when EP > weaveQuantum, else 1
• improved_particle_acceleratorsN multiplies by (upgradeLevel + 1) for that part level
• sub_atomic_catalysts multiplies by (1 − min(0.75, catalystReduction))

Display vent / transfer rates

session.resolveDisplayRates('vent1'); // or placed inst / def
resolvePartDisplayRates(id, session);
resolveDisplayRates(inst, session.grid, session.modifiers);

Returns { vent, transfer, containment, baseVent, baseTransfer, bonuses } using resolveVentRate / resolveTransferRate + grid plating/capacitor bonuses. Prefer this (or snapshot containmentSegments) over host tile.recalculateEffectiveValues / Part.getEffectiveVentValue.

Auto-replace costs

Aligned with host getAutoReplacementCost:

• non-perpetual → baseCost
• perpetual cell / reflector → baseCost * 1.5
• perpetual capacitor → baseCost * 10 (capacitorSellMultiplier, overridable via manifest.mechanics.autoReplace.capacitorSellMultiplier)

session.mechanicsOverrides.autoReplaceCosts and session.partAutoReplaceCost(id) rebuild on recompile from perpetual modifiers — hosts can stop feeding a sidecar every sync.

Layout caps (capacitor / plating)

Revival parts.json bakes host expansion for tiers 1–5:

• Capacitor: reactorPower = 100 * 140^(level-1), containment = 10 * 5^(level-1)
• Plating: reactorHeat = 250 * 150^(level-1)

recalculateCaps sums reactorPower into maxPower and reactorHeat into maxHeat. Hosts can drop applyLayoutCapsFromGame once on 1.2.5+.

Vent / transfer / containment rates

resolveVentRate / resolveTransferRate / resolveContainment use def base rates × compiled grid bonuses only. Host _effectiveVent / _effectiveTransfer / _effectiveContainment are ignored. Prefer session.resolveDisplayRates(...) for tooltips (see Display vent / transfer rates above).

Heat-flow vectors (presentation)

Problem: Host heat-flow renderers expect last-tick vectors { fromRow, fromCol, toRow, toCol, amount }.

Use:

session.getHeatFlowVectors();
session.engine.getLastHeatFlowVectors();
session.tick().heatFlowVectors;
session.getSnapshot().heatFlowVectors;

Recorded from valve/exchanger transfers every tick. Accessors and snapshots return copied frozen vectors (safe to retain across ticks).

Cell outputs (paused HUD / pulse display)

Do not recompute tile pulse/power in the host via computeCellOutput. Core owns live-cell coverage:

session.getCellOutputs();           // last tick or last refresh
session.getCellOutputAt(row, col);  // single tile
session.refreshCellOutputs();       // non-mutating reproject (place/remove/recompile also call this)
session.projectCellOutputs();       // same projection without writing engine state
session.getSnapshot().cellOutputs;  // alias lastCellOutputs

Each entry: { row, col, power, heat, pulse, pulseN, reflectorCount, heatBoost }. Guaranteed for every live cell (category === 'cell', ticks > 0) after each tick and after mid-UI grid sync (placeComponent / removeComponent / recompileModifiers).

Snapshot net change

getSnapshot() always sets numeric powerNetChange / heatNetChange (and heatRatio) from stats, falling back to deriveReactorStats when needed so hosts can drop overflow/auto-sell fallback math for live UI.

Modifier projection for tooltips / legacy tile code

Problem: Session modifiers are camelCase (ventEffectiveness). Host tile code often expects snake_case.

Use: session.hostModifiers / projectModifiersForHost(session.modifiers) / session.projectModifiers().

Upgrade display catalog

Prefer session.listUpgrades() for visible / classList / part / iconPath / affordance. Tech-tree gating: session.setCanPurchaseExtra(createTechTreePurchaseGate(...)).

Mechanics overrides

recompileModifiers owns session.mechanicsOverrides for: perpetual ids/categories, hasProtiumLoader, autoReplaceCosts, sellPriceMultiplier, autoSellPercent, alteredMaxPower, powerOverflowToHeatRatio. Stop merging a host sidecar for those keys.

Blueprint paste

| Need | API | | --- | --- | | Cost of an absolute layout | session.layoutCost(layout) / computeAbsoluteLayoutCost | | Diff money/EP breakdown | session.blueprintCostBreakdown(layout) | | What fits with current funds + sell credit | session.previewPartialBlueprint(layout) / filterAffordablePlacements | | Apply | APPLY_BLUEPRINT / COMMIT_BLUEPRINT_PLANNER |

Part cost policy — Default partCostForCell: (baseCost\|cost) * level; EP when erequires / currency==='ep' / ecost is set.

Objectives

session.getObjectiveProgress({ meltdown, hasMeltedDown, failure });
session.checkObjective(context);

Containment / vent display

• buildContainmentSegments / snapshot containmentSegments include fullness + vent/transfer rates.
• Active venting is intentional grid-wide capacitor level sum.
• Stats expose vent_multiplier_eff / transfer_multiplier_eff and additive percent aliases.

Tooltip / placement preview math

Prefer session.getPart / compilePartStats / getPartDescription / getCellOutputs for shop and tile tooltips. Keep string formatting in the host. Do not call computeCellOutput from host UI paths.

getPart / compilePartStats expose shop power / heat / heatBoost (forceful_fusion / heat_power_multiplier × log1000(currentHeat)). Drop host applyHeatPowerMultiplier.

Pipeline stages

session.getPipelineStages(); // e.g. revival: intents…achievements

Objectives / stats contract

Objective checks and deriveReactorStats use core cell coefficients. They must not require the host to write inst.power / inst.heat (layout overrides remain optional only).

Tick activity (L13 — adopt)

session.hasTickActivity(); // live grid parts OR auto-sell with power>0 OR pending SELL_POWER/VENT_HEAT/SELL_PART

Host: delete _hasSimulationActivity / production active_tiles rebuilds. Keep part-classification test-only if needed.

Cell pulse tooltips (L14 — adopt)

session.describeCellPulse(row, col);
// { cellMultiplier, pulseN, pulse, reflectorCount, neighbors: [{ kind, contribution, ... }] }

Also exported: computeNeighborPulseN, getCellOutputAt. Host: delete tooltip pulse duplication.

Economy single owner (L15 / L16)

Session economy is authoritative for money/EP. Mutate only via intents / session helpers; project host UI from snapshot after ticks:

session.dispatch({ type: 'DEBIT_MONEY' | 'CREDIT_MONEY' | 'DEBIT_EP' | 'CREDIT_EP', payload: { amount } });
session.dispatch({ type: 'GRANT_REWARD', payload: { money, ep } }); // or { reward } / { ep_reward }
session.grantReward({ money, ep }); // objectives call this on complete
session.loadEconomyState(data); // load/save ONLY — never each tick

Delete host syncEconomyFromGame / per-tick economy.deserialize, rewards.js Decimal writers, and prestige host EP credits (session.prestige() owns weave EP). Listen for economyChanged / rewardGranted or read getSnapshot().economy.

Prestige multiplier on credit (1.2.11 — adopt)

session.getPrestigeMultiplier(); // 1 + min(totalEP * perEp, cap)
session.creditMoney(amount, { applyPrestige: true }); // game.addMoney path
session.grantReward({ money, ep, applyPrestige: true });
session.dispatch({ type: 'CREDIT_MONEY', payload: { amount, applyPrestige: true } });

Session applies the EP money multiplier — host must not multiply before credit. Drop bridge getPrestigeMultiplier() multiply-before-credit; UI can still read session.getPrestigeMultiplier() for display.

Upgrade UI source (L17)

session.listUpgrades(); // level, nextLevel, cost, erequires, classList, canPurchase, …
session.getUpgradeLevel(id);
session.purchaseUpgrade(id); // sole runtime level mutation
session.setUpgradeLevels(entries); // load / one-shot bridge bootstrap only

Drop host UpgradeSet level authority and bridge upgrade-level sync after bootstrap.

Session command queue (L18 — adopt)

Session owns the intent/command queue. Host can delete state.intent_queue and push straight to session:

session.dispatch({ type: 'SELL_POWER' });
session.enqueueIntent({ action: 'PLACE_PART', payload: { row, col, partId } }); // partId → id
session.runCommand({ type: 'VENT_HEAT' }); // enqueue + drain now
session.drainCommands(); // apply pending outside tick
session.peekCommands();
session.clearCommands();
session.pendingCommands;

dispatch / enqueueIntent accept { type } or host { action }, and normalize partId / upgradeId → id. Tick still drains via the intents stage; use runCommand / drainCommands for immediate UI ops (place/sell/power).

Placed counts (L18 — adopt)

session.getPlacedCount(type, level);
session.incrementPlacedCount(type, level); // UnlockManager counters
session.rebuildPlacedCounts(); // from live grid (load / resync)
session.setPlacedCounts(map); // hydrate from save
session.clearPlacedCounts(); // prestige

PLACE_PART / PLACE_PART_PAID auto-increment on success. Direct placeComponent / blueprint apply do not (host parity). Prestige clears counts.

Active parts by category (L18 — adopt)

const parts = session.getActiveParts();
// parts.active_cells / .cells, .active_vents, .active_exchangers, …
session.getActivePartList('active_cells');
session.classifyActivePart(row, col);

Entries are { row, col, id, type, level, category, ticks, … } (not host Tile objects). Drop bridge-parts / Engine.active_* rebuilds for sim queries.

Neighbor topology for tooltips (1.2.10 — adopt)

const { containment, cell, reflector } = session.queryNeighbors(row, col);
// optional overrides: { range, topologyType }
session.countNeighborCategoryLevels(row, col, 'capacitor'); // active_venting tooltip

Matches host computeTileNeighborLists buckets (activated neighbors in part range/topology). Drop tooltip use of tile.containmentNeighborTiles / computeTileNeighborLists when ready.

Operator display titles (1.2.10 — adopt)

const entry = session.listUpgrades().find((u) => u.id === 'auto_sell_operator');
entry.displayTitle; // "Power Grid Sync"
entry.title;        // "Auto-Sell Operator"

auto_buy_operator → Supply Chain Logistics. Host can drop OPERATOR_HOST_TITLES and use displayTitle || title.

Valve / reflector catalog bake (1.2.12 — adopt)

session.getPart('overflow_valve').transfer; // baseTransfer × transferMultiplier (e.g. 1000×2.5)
session.getPart('reflector1').neighborPulseValue; // 1 + powerIncrease/100

Host can drop the valve multiply in applyCompiledCatalogPart. transferMultiplier remains on the compiled entry for display/debug.

Changelog

1.2.12

Compiled catalog bake:

• Valve transfer includes part transferMultiplier (runtime def + listParts/getPart)
• Reflector neighborPulseValue on compiled parts / defs

1.2.11

Economy prestige multiplier ownership:

• session.getPrestigeMultiplier()
• creditMoney / grantReward / CREDIT_MONEY accept { applyPrestige: true }
• Host drops multiply-before-credit via game.getPrestigeMultiplier

1.2.10

Tooltip neighbors + operator display titles:

• session.queryNeighbors(row,col) / countNeighborCategoryLevels — containment/cell/reflector lists for tooltips
• listUpgrades[].displayTitle for auto_sell_operator / auto_buy_operator host UI names

1.2.9

Shop heat-power, cellOutputs sync, pipeline stages, tick/economy ownership:

• Bake heat_power / forceful_fusion into getPart / compilePartStats shop power (+ heatBoost)
• projectCellOutputs / session.refreshCellOutputs — every live cell covered mid-UI without host computeCellOutput
• session.getPipelineStages(); objective/stats regression without inst.power/inst.heat
• session.hasTickActivity() — live parts / auto-sell power / pending sell-vent intents
• session.describeCellPulse(row,col) — structured pulse neighbor facts for tooltips
• Economy intents + grantReward / GRANT_REWARD; objectives auto-grant; loadEconomyState load-only
• listUpgrades richer catalog (nextLevel, erequires, baseCost); getUpgradeLevel / setUpgradeLevels
• Session command queue: enqueueIntent / runCommand / drainCommands / peekCommands (delete host intent_queue)
• getPlacedCount / incrementPlacedCount / rebuildPlacedCounts — UnlockManager counter ownership
• getActiveParts / getActivePartList — replace bridge-parts / Engine.active_*

1.2.8

Shop / stats / prestige cutover:

• Bake cell_power into compiled cell basePower (×2^level); runtime coeffs use the baked value
• Bake PA epHeat via resolveEpHeat / session.resolveEpHeat / getPart.epHeat (EP log scale + IPA + catalyst); tick EP chance uses the same threshold
• Plating reactorHeat no longer floored (ceramic_composite shop parity)
• Snapshot / stats prefer mechanicsOverrides.autoSellPercent (control-deck) over upgrade-only percent
• session.prestige() / reboot({ keepEp }) keep EP upgrades, clear money upgrades, then recompile; preferred sole reboot owner

1.2.7

Host display / prestige / auto-replace cutover:

• session.listParts / getPart / listCompiledParts — post-recompile part catalog for shop/tooltips
• Catalog parity: vent/exchanger +100% boosts, reflector duration/power, experimental fluid/fractal/ultracryonics/full_spectrum
• session.resolveDisplayRates / resolvePartDisplayRates — vent/transfer/containment display helper
• session.previewPrestige / prestige / calculatePrestigeReward / calculateWeaveEp — weave EP ownership
• Auto-replace costs: perpetual cell/reflector 1.5×, perpetual capacitor 10×, else baseCost
• Document session.computeSellValue(row,col) as authoritative sell preview (fractional isotope baseTicks)

1.2.6

Reinforcement, isotope sell parity, operators, achievement engine gaps:

• Wire component_reinforcement (+10%/level) into capacitor/coolant containment and plating reactorHeat; refresh placed defs on recompile
• Fractional Isotope Stabilization baseTicks for sell ratios; floor for runtime ticks
• inst.power/inst.heat layout overrides (drop _effective* bridge when ready); honorHostEffective remains transitional
• auto_sell_operator / auto_buy_operator upgrade defs; upgrade flags OR with toggles
• Prestige achievements gated on keepEp === true; prestigeCompleted payload support
• criticality_recovery_auto uses soldHeatCount (monotonic full-vent counter) so a vent after entry aborts even if heat was cleared earlier
• Persist achievement trackers + sustained state; unlockedAchievementIds on tick result; ACHIEVEMENT_UNLOCKED event alias

1.2.5

Host cutover follow-ups:

• Cap sell life ratio at 1; reject non-finite custom sell policies
• cellPhase reads mechanicsOverrides.honorHostEffective (matches stats)
• Package regression tests (npm test)
• Snapshot always populates powerNetChange / heatNetChange; persists frozen cellOutputs / lastCellOutputs
• Bake capacitor/plating tier-scaled reactorPower / containment / reactorHeat; recalculateCaps applies reactorHeat
• Vent/transfer/containment resolve from defs + modifiers only (ignore host _effective*)
• Export countActiveReflectorNeighbors / copyCellOutputs / session.getCellOutputs

1.2.4

Host cutover Q–U:

• SELL_PART / computeInstanceSellValue life-ratio and containment-damage refunds (optional sellValuePolicy)
• Revival dual/quad cells: basePower/baseHeat = single-cell coefficient (pulse uses cellMultiplier)
• deriveReactorStats passes honorHostEffective into cell coeff options
• Last-tick heatFlowVectors on tick result, snapshot, engine.getLastHeatFlowVectors, session.getHeatFlowVectors (copied/frozen)
• placeComponentPaid rejects bounds / occupied before debit; placeComponent returns false on OOB
• Instance-mode sell credit is actionable: sellAllComponents / APPLY_BLUEPRINT accept sellMode: 'instance' / lifeRatio
• APPLY_BLUEPRINT + sellExisting pre-flights affordability before sell (no destructive deficit)
• computeGridSellCredit always returns sellMultiplier (including empty/no-grid)
• Paid/free place and SELL_PART reject non-integer / non-finite coords via isValidGridCoord before any debit

1.2.3

Host cutover L–O — place/debit atomicity, sell preview, modifier aliases, richer upgrade catalog:

• Atomic paid place: PLACE_PART + paid: true, PLACE_PART_PAID, session.placeComponentPaid (debit via partCostForCell, refund on place failure)
• Non-mutating computeGridSellCredit / session.computeGridSellCredit for paste sell-credit UI
• projectModifiersForHost / MODIFIER_HOST_ALIASES / session.hostModifiers / session.projectModifiers (camelCase + snake_case)
• Richer listDisplayCatalog: visible / unlockVisible, classList, part, iconPath

1.2.2

Paste / objective / containment host cutover APIs:

• Export filterAffordablePlacements, previewPartialBlueprint, computeAbsoluteLayoutCost, partCostForCell, partUsesEp
• Session helpers: previewPartialBlueprint, filterAffordablePlacements, layoutCost, blueprintCostBreakdown, getObjectiveProgress, checkObjective
• Objective progress accepts { meltdown, hasMeltedDown, failure } context (no engine.meltdown patching)
• buildContainmentSegments / snapshot containmentSegments include fullness + resolved vent/transfer rates
• Document part-cost policy and intentional grid-wide active_venting

1.2.1

Host cutover leftovers (formerly unlogged 1.2.0 surface) plus follow-up override/catalog polish:

• Tech-tree purchase gating via createTechTreePurchaseGate / session.setCanPurchaseExtra
• In-core effective vent/transfer from defs + modifiers + plating/capacitor grid bonuses
• Stats expose full and additive vent/transfer multipliers
• Full cell upgrade catalog (cell_tick / cell_perpetual) + previewPurchase / listUpgrades / isUpgradeAvailable
• heatPowerMultiplier on runCellPhase / cellOutputs
• Core-owned mechanicsOverrides sync: protium loader, auto-replace costs, sell price, auto-sell %, altered max power, overflow ratio
• Blueprint part costs honor erequires / Decimal when available

1.1.0

Revival cutover APIs: failure ownership fields/events, upgrade purchase policy, layout caps from reactorPower/reactorHeat, cell pulse coefficients in core (family _cell_power by type), partial VENT_HEAT, snapshot net-change / heat warning facts, containment segments export, blueprint cost helper.