diff --git a/src/progression/modules.js b/src/progression/modules.js
new file mode 100644
index 0000000..6cc6780
--- /dev/null
+++ b/src/progression/modules.js
@@ -0,0 +1,125 @@
+export const SHIP_BASE_STATS = {
+  maxHull: 100,
+  maxSpeed: 180,
+  reverseSpeed: -55,
+  acceleration: 92,
+  brake: 118,
+  turnRate: 76,
+  reloadMs: 850,
+  cannonDamage: 16,
+  windExposure: 1,
+  cargoCapacity: 4,
+  salvageCapacity: 2,
+  radarRange: 900,
+};
+
+export const MODULE_CATALOG = {
+  'stock-engine': {
+    id: 'stock-engine',
+    name: 'Stock Twin Propellers',
+    slot: 'engine',
+    rarity: 'common',
+    price: 0,
+    modifiers: {},
+  },
+  'tuned-propellers': {
+    id: 'tuned-propellers',
+    name: 'Tuned Propellers',
+    slot: 'engine',
+    rarity: 'improved',
+    price: 280,
+    modifiers: { maxSpeed: 20, acceleration: 10 },
+  },
+  'corsair-overdrive': {
+    id: 'corsair-overdrive',
+    name: 'Corsair Overdrive',
+    slot: 'engine',
+    rarity: 'rare',
+    price: 690,
+    modifiers: { maxSpeed: 34, acceleration: 18, turnRate: -5 },
+  },
+  'standard-broadside': {
+    id: 'standard-broadside',
+    name: 'Standard Broadside',
+    slot: 'weapon',
+    rarity: 'common',
+    price: 0,
+    modifiers: {},
+  },
+  'long-nine-cannons': {
+    id: 'long-nine-cannons',
+    name: 'Long Nine Cannons',
+    slot: 'weapon',
+    rarity: 'improved',
+    price: 360,
+    modifiers: { cannonDamage: 4, reloadMs: 70 },
+  },
+  'quicklock-breeches': {
+    id: 'quicklock-breeches',
+    name: 'Quicklock Breeches',
+    slot: 'weapon',
+    rarity: 'rare',
+    price: 620,
+    modifiers: { cannonDamage: 2, reloadMs: -180 },
+  },
+  'timber-hull': {
+    id: 'timber-hull',
+    name: 'Timber Hull',
+    slot: 'hull',
+    rarity: 'common',
+    price: 0,
+    modifiers: {},
+  },
+  'reinforced-keel': {
+    id: 'reinforced-keel',
+    name: 'Reinforced Keel',
+    slot: 'hull',
+    rarity: 'improved',
+    price: 420,
+    modifiers: { maxHull: 28, maxSpeed: -7 },
+  },
+  'stormglass-nav': {
+    id: 'stormglass-nav',
+    name: 'Stormglass Navigator',
+    slot: 'navigation',
+    rarity: 'rare',
+    price: 560,
+    modifiers: { windExposure: -0.22, radarRange: 240 },
+  },
+  'brass-compass': {
+    id: 'brass-compass',
+    name: 'Brass Compass',
+    slot: 'navigation',
+    rarity: 'common',
+    price: 0,
+    modifiers: {},
+  },
+  'salvage-rig': {
+    id: 'salvage-rig',
+    name: 'Deck Salvage Rig',
+    slot: 'utility',
+    rarity: 'improved',
+    price: 330,
+    modifiers: { salvageCapacity: 2 },
+  },
+  'expanded-hold': {
+    id: 'expanded-hold',
+    name: 'Expanded Cargo Hold',
+    slot: 'cargo',
+    rarity: 'improved',
+    price: 350,
+    modifiers: { cargoCapacity: 4, maxSpeed: -4 },
+  },
+};
+
+export const STARTER_LOADOUT = {
+  engine: 'stock-engine',
+  weapon: 'standard-broadside',
+  hull: 'timber-hull',
+  navigation: 'brass-compass',
+  utility: null,
+  cargo: null,
+};
+
+export const purchasableModules = () => Object.values(MODULE_CATALOG)
+  .filter((module) => module.price > 0);
diff --git a/src/progression/ship-loadout.js b/src/progression/ship-loadout.js
new file mode 100644
index 0000000..43c3652
--- /dev/null
+++ b/src/progression/ship-loadout.js
@@ -0,0 +1,153 @@
+import {
+  MODULE_CATALOG,
+  SHIP_BASE_STATS,
+  STARTER_LOADOUT,
+  purchasableModules,
+} from './modules.js';
+import { createSeededRandom } from '../world/seeded-random.js';
+
+const clamp = (value, min, max) => Math.max(min, Math.min(max, value));
+
+export const createStarterProgression = () => ({
+  credits: 650,
+  scrap: 0,
+  loadout: { ...STARTER_LOADOUT },
+  inventory: [],
+});
+
+export const deriveShipStats = (loadout = STARTER_LOADOUT) => {
+  const stats = { ...SHIP_BASE_STATS };
+
+  for (const moduleId of Object.values(loadout)) {
+    if (!moduleId) continue;
+    const module = MODULE_CATALOG[moduleId];
+    if (!module) continue;
+    for (const [key, value] of Object.entries(module.modifiers || {})) {
+      stats[key] = (stats[key] ?? 0) + value;
+    }
+  }
+
+  stats.maxHull = Math.max(1, stats.maxHull);
+  stats.maxSpeed = Math.max(40, stats.maxSpeed);
+  stats.acceleration = Math.max(10, stats.acceleration);
+  stats.turnRate = Math.max(15, stats.turnRate);
+  stats.reloadMs = Math.max(260, stats.reloadMs);
+  stats.cannonDamage = Math.max(1, stats.cannonDamage);
+  stats.windExposure = clamp(stats.windExposure, 0.35, 1.5);
+  stats.cargoCapacity = Math.max(1, Math.floor(stats.cargoCapacity));
+  stats.salvageCapacity = Math.max(1, Math.floor(stats.salvageCapacity));
+  return stats;
+};
+
+export const installModule = (progression, moduleId) => {
+  const module = MODULE_CATALOG[moduleId];
+  if (!module) return { ...progression, installed: false, reason: 'unknown-module' };
+
+  const inventory = [...(progression.inventory || [])];
+  const inventoryIndex = inventory.indexOf(moduleId);
+  if (inventoryIndex >= 0) inventory.splice(inventoryIndex, 1);
+
+  const loadout = { ...(progression.loadout || STARTER_LOADOUT) };
+  const replaced = loadout[module.slot] || null;
+  loadout[module.slot] = moduleId;
+  if (replaced && MODULE_CATALOG[replaced]?.price > 0) inventory.push(replaced);
+
+  return {
+    ...progression,
+    loadout,
+    inventory,
+    installed: true,
+    replaced,
+    installedModule: moduleId,
+  };
+};
+
+export const buyAndInstallModule = (progression, moduleId) => {
+  const module = MODULE_CATALOG[moduleId];
+  if (!module || module.price <= 0) return { ...progression, purchased: false, reason: 'not-for-sale' };
+  if ((progression.credits || 0) < module.price) {
+    return { ...progression, purchased: false, reason: 'insufficient-credits' };
+  }
+
+  const purchased = {
+    ...progression,
+    credits: progression.credits - module.price,
+    inventory: [...(progression.inventory || []), moduleId],
+  };
+  return { ...installModule(purchased, moduleId), purchased: true };
+};
+
+export const marketForPort = (port) => {
+  const stock = purchasableModules().filter((module) => {
+    if (port?.type === 'industrial') return ['engine', 'hull', 'utility', 'cargo'].includes(module.slot);
+    if (port?.type === 'military') return ['weapon', 'hull', 'navigation'].includes(module.slot);
+    if (port?.type === 'fuel') return ['engine', 'navigation', 'cargo'].includes(module.slot);
+    return true;
+  });
+
+  return stock.sort((a, b) => a.price - b.price);
+};
+
+export const salvageForPirate = ({
+  seed = 'salvage',
+  classKey = 'raider',
+  wave = 1,
+  sequence = 0,
+} = {}) => {
+  const random = createSeededRandom(`${seed}:${classKey}:${wave}:${sequence}`);
+  const chance = classKey === 'captain' ? 0.86 : classKey === 'frigate' ? 0.62 : 0.42;
+  const modulePool = purchasableModules();
+  const module = random() < chance
+    ? modulePool[Math.floor(random() * modulePool.length)]
+    : null;
+  const scrap = 1 + Math.floor(random() * (classKey === 'captain' ? 8 : classKey === 'frigate' ? 5 : 3));
+  const credits = 20 + Math.floor(random() * (35 + wave * 8));
+
+  return {
+    moduleId: module?.id || null,
+    scrap,
+    credits,
+    condition: module ? clamp(0.28 + random() * 0.67, 0.28, 0.95) : null,
+  };
+};
+
+export const collectSalvage = (progression, salvage, stats = deriveShipStats(progression.loadout)) => {
+  const inventory = [...(progression.inventory || [])];
+  let moduleCollected = false;
+
+  if (salvage?.moduleId && inventory.length < stats.salvageCapacity) {
+    inventory.push(salvage.moduleId);
+    moduleCollected = true;
+  }
+
+  return {
+    ...progression,
+    inventory,
+    scrap: (progression.scrap || 0) + Math.max(0, salvage?.scrap || 0),
+    credits: (progression.credits || 0) + Math.max(0, salvage?.credits || 0),
+    lastSalvage: { ...salvage, moduleCollected },
+  };
+};
+
+export const bestAffordableMarketUpgrade = (progression, port) => {
+  const stats = deriveShipStats(progression.loadout);
+  const candidates = marketForPort(port)
+    .filter((module) => module.price <= (progression.credits || 0))
+    .filter((module) => progression.loadout?.[module.slot] !== module.id)
+    .map((module) => {
+      const next = deriveShipStats({ ...progression.loadout, [module.slot]: module.id });
+      const score = (next.maxHull - stats.maxHull) * 0.7
+        + (next.maxSpeed - stats.maxSpeed)
+        + (next.acceleration - stats.acceleration) * 0.45
+        + (next.turnRate - stats.turnRate) * 0.35
+        + (stats.reloadMs - next.reloadMs) * 0.06
+        + (next.cannonDamage - stats.cannonDamage) * 5
+        + (stats.windExposure - next.windExposure) * 30
+        + (next.salvageCapacity - stats.salvageCapacity) * 8
+        + (next.cargoCapacity - stats.cargoCapacity) * 4;
+      return { module, score };
+    })
+    .sort((a, b) => b.score - a.score);
+
+  return candidates[0]?.module || null;
+};
diff --git a/src/world/seeded-random.js b/src/world/seeded-random.js
new file mode 100644
index 0000000..6a0cd4a
--- /dev/null
+++ b/src/world/seeded-random.js
@@ -0,0 +1,22 @@
+export const hashSeed = (seed = '') => {
+  let hash = 2166136261;
+  for (const char of String(seed)) {
+    hash ^= char.charCodeAt(0);
+    hash = Math.imul(hash, 16777619);
+  }
+  return hash >>> 0;
+};
+
+export const createSeededRandom = (seed = '') => {
+  let state = hashSeed(seed) || 0x6d2b79f5;
+  return () => {
+    state += 0x6d2b79f5;
+    let value = state;
+    value = Math.imul(value ^ (value >>> 15), value | 1);
+    value ^= value + Math.imul(value ^ (value >>> 7), value | 61);
+    return ((value ^ (value >>> 14)) >>> 0) / 4294967296;
+  };
+};
+
+export const randomBetween = (random, min, max) => min + (max - min) * random();
+export const randomInt = (random, min, max) => Math.floor(randomBetween(random, min, max + 1));
diff --git a/src/world/world-generator.js b/src/world/world-generator.js
new file mode 100644
index 0000000..dfe8602
--- /dev/null
+++ b/src/world/world-generator.js
@@ -0,0 +1,262 @@
+import { createSeededRandom, randomBetween, randomInt } from './seeded-random.js';
+
+const clamp = (value, min, max) => Math.max(min, Math.min(max, value));
+const distance = (a, b) => Math.hypot(a.x - b.x, a.y - b.y);
+
+const pointSegmentDistance = (point, start, end) => {
+  const dx = end.x - start.x;
+  const dy = end.y - start.y;
+  const lengthSquared = dx * dx + dy * dy;
+  if (lengthSquared <= 0) return distance(point, start);
+  const t = clamp(((point.x - start.x) * dx + (point.y - start.y) * dy) / lengthSquared, 0, 1);
+  return Math.hypot(point.x - (start.x + dx * t), point.y - (start.y + dy * t));
+};
+
+const nearestPortDistance = (island, ports) => ports.length
+  ? Math.min(...ports.map((port) => distance(island, port)))
+  : Infinity;
+
+const createRegions = (random, width, height) => {
+  const types = ['trade', 'settled', 'frontier', 'pirate', 'weather', 'frontier'];
+  return types.map((type, index) => ({
+    id: `region-${index + 1}`,
+    type,
+    x: randomBetween(random, width * 0.15, width * 0.85),
+    y: randomBetween(random, height * 0.15, height * 0.85),
+    radius: randomBetween(random, width * 0.18, width * 0.32),
+    wealth: type === 'trade' ? randomBetween(random, 0.72, 0.96) : randomBetween(random, 0.25, 0.78),
+    security: type === 'settled' ? randomBetween(random, 0.72, 0.95)
+      : type === 'pirate' ? randomBetween(random, 0.05, 0.25)
+        : randomBetween(random, 0.28, 0.68),
+    weatherSeverity: type === 'weather' ? randomBetween(random, 0.72, 0.98) : randomBetween(random, 0.12, 0.7),
+  }));
+};
+
+const generateIslands = (random, width, height, count) => {
+  const islands = [];
+  const margin = Math.min(width, height) * 0.07;
+  const minSpacing = Math.min(width, height) * 0.085;
+
+  for (let attempt = 0; islands.length < count && attempt < count * 80; attempt += 1) {
+    const radius = randomBetween(random, 68, 148);
+    const candidate = {
+      id: `island-${islands.length + 1}`,
+      x: randomBetween(random, margin + radius, width - margin - radius),
+      y: randomBetween(random, margin + radius, height - margin - radius),
+      radius,
+      turbulenceRadius: radius * randomBetween(random, 2.2, 2.9),
+      settlementRoll: random(),
+      resource: ['timber', 'ore', 'food', 'fuel'][randomInt(random, 0, 3)],
+    };
+
+    if (islands.every((other) => distance(candidate, other) >= minSpacing + radius + other.radius * 0.35)) {
+      islands.push(candidate);
+    }
+  }
+
+  return islands;
+};
+
+const generatePorts = (random, islands, count) => {
+  const selected = [...islands]
+    .sort((a, b) => b.settlementRoll - a.settlementRoll)
+    .slice(0, Math.min(count, islands.length));
+
+  return selected.map((island, index) => {
+    const portType = index === 0 ? 'capital'
+      : island.resource === 'ore' ? 'industrial'
+        : island.resource === 'fuel' ? 'fuel'
+          : index % 3 === 0 ? 'military'
+            : 'trade';
+    const baseSecurity = portType === 'capital' ? 0.92
+      : portType === 'military' ? 0.82
+        : randomBetween(random, 0.42, 0.76);
+
+    return {
+      id: `port-${index + 1}`,
+      islandId: island.id,
+      name: index === 0 ? 'Aerie Harbour' : `Skyport ${index + 1}`,
+      x: island.x,
+      y: island.y,
+      type: portType,
+      wealth: portType === 'capital' ? 0.9 : randomBetween(random, 0.38, 0.88),
+      security: baseSecurity,
+      exports: [island.resource],
+      imports: island.resource === 'food' ? ['ore'] : ['food'],
+    };
+  });
+};
+
+const routeKey = (a, b) => [a.id, b.id].sort().join(':');
+
+const generateTradeRoutes = (random, ports) => {
+  if (ports.length < 2) return [];
+  const routes = [];
+  const connected = new Set([ports[0].id]);
+  const used = new Set();
+
+  while (connected.size < ports.length) {
+    let best = null;
+    for (const from of ports) {
+      if (!connected.has(from.id)) continue;
+      for (const to of ports) {
+        if (connected.has(to.id)) continue;
+        const cost = distance(from, to);
+        if (!best || cost < best.cost) best = { from, to, cost };
+      }
+    }
+    if (!best) break;
+    connected.add(best.to.id);
+    used.add(routeKey(best.from, best.to));
+    routes.push({ from: best.from, to: best.to });
+  }
+
+  const candidates = [];
+  for (let i = 0; i < ports.length; i += 1) {
+    for (let j = i + 1; j < ports.length; j += 1) {
+      if (used.has(routeKey(ports[i], ports[j]))) continue;
+      candidates.push({ from: ports[i], to: ports[j], cost: distance(ports[i], ports[j]) });
+    }
+  }
+
+  candidates.sort((a, b) => a.cost - b.cost);
+  for (const candidate of candidates.slice(0, Math.max(1, Math.floor(ports.length / 3)))) {
+    if (random() < 0.72) routes.push(candidate);
+  }
+
+  return routes.map(({ from, to }, index) => {
+    const traffic = clamp((from.wealth + to.wealth) / 2 + randomBetween(random, -0.08, 0.08), 0.2, 1);
+    const security = clamp((from.security + to.security) / 2 + randomBetween(random, -0.12, 0.06), 0.1, 0.95);
+    return {
+      id: `route-${index + 1}`,
+      fromPortId: from.id,
+      toPortId: to.id,
+      from: { x: from.x, y: from.y },
+      to: { x: to.x, y: to.y },
+      traffic,
+      value: clamp(traffic * ((from.wealth + to.wealth) / 2), 0.1, 1),
+      security,
+      width: randomBetween(random, 150, 280),
+    };
+  });
+};
+
+const generatePirateTerritories = (random, islands, ports, routes, count = 3) => {
+  if (!islands.length || !routes.length) return [];
+
+  const candidates = islands
+    .filter((island) => !ports.some((port) => port.islandId === island.id))
+    .map((island) => {
+      let bestRoute = null;
+      let routeDistance = Infinity;
+      for (const route of routes) {
+        const candidateDistance = pointSegmentDistance(island, route.from, route.to);
+        if (candidateDistance < routeDistance) {
+          routeDistance = candidateDistance;
+          bestRoute = route;
+        }
+      }
+      const remoteness = clamp(nearestPortDistance(island, ports) / 900, 0, 1);
+      const opportunity = bestRoute ? bestRoute.value * (1 - bestRoute.security * 0.55) : 0;
+      const proximity = clamp(1 - routeDistance / 1000, 0, 1);
+      return {
+        island,
+        route: bestRoute,
+        score: opportunity * 0.52 + proximity * 0.28 + remoteness * 0.2 + randomBetween(random, 0, 0.08),
+      };
+    })
+    .sort((a, b) => b.score - a.score)
+    .slice(0, Math.min(count, Math.max(1, candidatesLength(islands, ports))));
+
+  return candidates.map(({ island, route, score }, index) => ({
+    id: `pirate-territory-${index + 1}`,
+    name: ['Blackwake Reach', 'Corsair Belt', 'Red Lantern Expanse'][index] || `Pirate Reach ${index + 1}`,
+    center: { x: island.x, y: island.y },
+    radius: randomBetween(random, 460, 760),
+    strength: clamp(0.45 + score * 0.55, 0.45, 1),
+    aggression: randomBetween(random, 0.62, 0.95),
+    havenIslandId: island.id,
+    targetRouteId: route?.id || null,
+  }));
+};
+
+const candidatesLength = (islands, ports) => Math.max(
+  0,
+  islands.length - new Set(ports.map((port) => port.islandId)).size,
+);
+
+export const generateWorld = ({
+  seed = 'SKYWARD-001',
+  width = 3600,
+  height = 3600,
+  islandCount = 16,
+  portCount = 7,
+} = {}) => {
+  const random = createSeededRandom(seed);
+  const regions = createRegions(random, width, height);
+  const islands = generateIslands(random, width, height, islandCount);
+  const ports = generatePorts(random, islands, portCount);
+  const tradeRoutes = generateTradeRoutes(random, ports);
+  const pirateTerritories = generatePirateTerritories(random, islands, ports, tradeRoutes, 3);
+  const starterPort = [...ports].sort((a, b) => b.security - a.security)[0]
+    || { x: width / 2, y: height / 2 };
+
+  return {
+    seed,
+    width,
+    height,
+    regions,
+    islands,
+    ports,
+    tradeRoutes,
+    pirateTerritories,
+    spawn: {
+      x: clamp(starterPort.x + 120, 120, width - 120),
+      y: clamp(starterPort.y + 150, 120, height - 120),
+      portId: starterPort.id || null,
+    },
+  };
+};
+
+export const pirateInfluenceAt = (world, x, y) => {
+  let influence = 0;
+  for (const territory of world?.pirateTerritories || []) {
+    const dist = Math.hypot(x - territory.center.x, y - territory.center.y);
+    if (dist >= territory.radius) continue;
+    influence = Math.max(influence, (1 - dist / territory.radius) * territory.strength);
+  }
+  return clamp(influence, 0, 1);
+};
+
+export const nearestPort = (world, x, y) => {
+  let result = null;
+  let range = Infinity;
+  for (const port of world?.ports || []) {
+    const candidate = Math.hypot(x - port.x, y - port.y);
+    if (candidate < range) {
+      result = port;
+      range = candidate;
+    }
+  }
+  return { port: result, range };
+};
+
+export const pirateSpawnPointsForWave = (world, player, count, wave = 1) => {
+  const territories = [...(world?.pirateTerritories || [])]
+    .sort((a, b) => distance(a.center, player) - distance(b.center, player));
+  const territory = territories[(Math.max(1, wave) - 1) % Math.max(1, territories.length)];
+  const center = territory?.center || player;
+  const radius = territory ? Math.min(territory.radius * 0.62, 520) : 520;
+  const random = createSeededRandom(`${world?.seed || 'world'}:wave:${wave}`);
+
+  return Array.from({ length: count }, (_, index) => {
+    const angle = (Math.PI * 2 * index / Math.max(1, count)) + randomBetween(random, -0.28, 0.28);
+    const spread = radius * randomBetween(random, 0.62, 1);
+    return {
+      x: clamp(center.x + Math.cos(angle) * spread, 120, (world?.width || 3600) - 120),
+      y: clamp(center.y + Math.sin(angle) * spread, 120, (world?.height || 3600) - 120),
+      angle,
+      territoryId: territory?.id || null,
+    };
+  });
+};
diff --git a/tests/progression.test.mjs b/tests/progression.test.mjs
new file mode 100644
index 0000000..d2fdb49
--- /dev/null
+++ b/tests/progression.test.mjs
@@ -0,0 +1,55 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  bestAffordableMarketUpgrade,
+  buyAndInstallModule,
+  collectSalvage,
+  createStarterProgression,
+  deriveShipStats,
+  installModule,
+  salvageForPirate,
+} from '../src/progression/ship-loadout.js';
+
+test('starter loadout preserves current ship combat and handling values', () => {
+  const progression = createStarterProgression();
+  const stats = deriveShipStats(progression.loadout);
+  assert.equal(stats.maxHull, 100);
+  assert.equal(stats.maxSpeed, 180);
+  assert.equal(stats.turnRate, 76);
+  assert.equal(stats.reloadMs, 850);
+  assert.equal(stats.cannonDamage, 16);
+});
+
+test('installed modules derive meaningful ship stat changes', () => {
+  const progression = installModule(createStarterProgression(), 'corsair-overdrive');
+  const stats = deriveShipStats(progression.loadout);
+  assert.equal(stats.maxSpeed, 214);
+  assert.equal(stats.acceleration, 110);
+  assert.equal(stats.turnRate, 71);
+});
+
+test('port purchase deducts credits and installs the module', () => {
+  const starter = createStarterProgression();
+  const result = buyAndInstallModule(starter, 'tuned-propellers');
+  assert.equal(result.purchased, true);
+  assert.equal(result.credits, starter.credits - 280);
+  assert.equal(result.loadout.engine, 'tuned-propellers');
+});
+
+test('pirate salvage is deterministic and collectible within salvage capacity', () => {
+  const salvageA = salvageForPirate({ seed: 'WORLD', classKey: 'captain', wave: 4, sequence: 2 });
+  const salvageB = salvageForPirate({ seed: 'WORLD', classKey: 'captain', wave: 4, sequence: 2 });
+  assert.deepEqual(salvageA, salvageB);
+
+  const starter = createStarterProgression();
+  const collected = collectSalvage(starter, salvageA);
+  assert.ok(collected.credits >= starter.credits);
+  assert.ok(collected.scrap >= starter.scrap);
+});
+
+test('market can select an affordable upgrade for a port', () => {
+  const starter = createStarterProgression();
+  const upgrade = bestAffordableMarketUpgrade(starter, { type: 'military' });
+  assert.ok(upgrade);
+  assert.ok(upgrade.price <= starter.credits);
+});
diff --git a/tests/world-generator.test.mjs b/tests/world-generator.test.mjs
new file mode 100644
index 0000000..a9fe9e3
--- /dev/null
+++ b/tests/world-generator.test.mjs
@@ -0,0 +1,61 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  generateWorld,
+  nearestPort,
+  pirateInfluenceAt,
+  pirateSpawnPointsForWave,
+} from '../src/world/world-generator.js';
+
+test('world generation is deterministic for a seed', () => {
+  const a = generateWorld({ seed: 'TEST-SEED', width: 3600, height: 3600 });
+  const b = generateWorld({ seed: 'TEST-SEED', width: 3600, height: 3600 });
+  assert.deepEqual(a, b);
+});
+
+test('different seeds create different geography', () => {
+  const a = generateWorld({ seed: 'A' });
+  const b = generateWorld({ seed: 'B' });
+  assert.notDeepEqual(a.islands, b.islands);
+});
+
+test('generated world contains ports, trade routes, and pirate territory', () => {
+  const world = generateWorld({ seed: 'TRADE-WORLD' });
+  assert.ok(world.islands.length >= 10);
+  assert.ok(world.ports.length >= 4);
+  assert.ok(world.tradeRoutes.length >= world.ports.length - 1);
+  assert.ok(world.pirateTerritories.length >= 1);
+
+  const portIds = new Set(world.ports.map(({ id }) => id));
+  for (const route of world.tradeRoutes) {
+    assert.ok(portIds.has(route.fromPortId));
+    assert.ok(portIds.has(route.toPortId));
+    assert.ok(route.value > 0);
+  }
+});
+
+test('pirate influence peaks inside generated pirate territory', () => {
+  const world = generateWorld({ seed: 'BLACKWAKE' });
+  const territory = world.pirateTerritories[0];
+  assert.ok(territory);
+  assert.ok(pirateInfluenceAt(world, territory.center.x, territory.center.y) >= 0.4);
+});
+
+test('wave spawns originate around generated pirate territory and remain in bounds', () => {
+  const world = generateWorld({ seed: 'SPAWN-WORLD' });
+  const player = { x: world.spawn.x, y: world.spawn.y };
+  const points = pirateSpawnPointsForWave(world, player, 5, 3);
+  assert.equal(points.length, 5);
+  for (const point of points) {
+    assert.ok(point.x >= 120 && point.x <= world.width - 120);
+    assert.ok(point.y >= 120 && point.y <= world.height - 120);
+    assert.ok(point.territoryId);
+  }
+});
+
+test('nearestPort reports the generated starter port nearby', () => {
+  const world = generateWorld({ seed: 'PORT-WORLD' });
+  const result = nearestPort(world, world.spawn.x, world.spawn.y);
+  assert.ok(result.port);
+  assert.ok(result.range < 400);
+});