diff --git a/server/src/industry/__tests__/inventionRegistrar.test.ts b/server/src/industry/__tests__/inventionRegistrar.test.ts
new file mode 100644
index 0000000..af52355
--- /dev/null
+++ b/server/src/industry/__tests__/inventionRegistrar.test.ts
@@ -0,0 +1,97 @@
+import { describe, it, expect } from 'vitest';
+import { registerInvention } from '../inventionRegistrar.js';
+import { ItemRegistry } from '../itemRegistry.js';
+import { RecipeRegistry } from '../recipeRegistry.js';
+import { createInventionTimeline } from '../inventionTimeline.js';
+import type { RawInvention } from '../inventionValidator.js';
+
+function createRegistries() {
+  return {
+    itemRegistry: ItemRegistry.createDefault(),
+    recipeRegistry: RecipeRegistry.createDefault(),
+    timeline: createInventionTimeline(),
+  };
+}
+
+describe('registerInvention', () => {
+  it('registers new item and recipe', () => {
+    const { itemRegistry, recipeRegistry, timeline } = createRegistries();
+    const raw: RawInvention = {
+      name: 'rope',
+      description: 'Twisted plant fibers',
+      category: 'material',
+      inputs: [{ itemId: 'log', quantity: 2 }],
+    };
+
+    const result = registerInvention({
+      raw,
+      itemId: 'rope',
+      itemRegistry,
+      recipeRegistry,
+      timeline,
+      inventorEntityId: 1,
+      inventorName: 'Gwen',
+      tick: 500,
+      day: 2,
+    });
+
+    expect(result).toBe(true);
+    expect(itemRegistry.get('rope')).toBeDefined();
+    expect(itemRegistry.get('rope')!.source).toBe('invented');
+    expect(itemRegistry.get('rope')!.inventedBy!.name).toBe('Gwen');
+    expect(recipeRegistry.get('craft_rope')).toBeDefined();
+    expect(recipeRegistry.get('craft_rope')!.source).toBe('invented');
+    expect(timeline.getAll()).toHaveLength(1);
+  });
+
+  it('registers structure recipe with build_ prefix', () => {
+    const { itemRegistry, recipeRegistry, timeline } = createRegistries();
+    const raw: RawInvention = {
+      name: 'kiln',
+      description: 'A stone furnace',
+      category: 'structure',
+      inputs: [{ itemId: 'stone', quantity: 5 }],
+      workshopType: 'kiln',
+    };
+
+    registerInvention({
+      raw,
+      itemId: 'kiln',
+      itemRegistry,
+      recipeRegistry,
+      timeline,
+      inventorEntityId: 2,
+      inventorName: 'Bram',
+      tick: 700,
+      day: 3,
+    });
+
+    expect(recipeRegistry.get('build_kiln')).toBeDefined();
+    expect(recipeRegistry.get('build_kiln')!.outputItemId).toBe('kiln');
+  });
+
+  it('includes toolRequired in recipe', () => {
+    const { itemRegistry, recipeRegistry, timeline } = createRegistries();
+    const raw: RawInvention = {
+      name: 'plank',
+      description: 'A wooden plank',
+      category: 'material',
+      inputs: [{ itemId: 'log', quantity: 1 }],
+      toolRequired: 'wooden_axe',
+    };
+
+    registerInvention({
+      raw,
+      itemId: 'plank',
+      itemRegistry,
+      recipeRegistry,
+      timeline,
+      inventorEntityId: 1,
+      inventorName: 'Gwen',
+      tick: 500,
+      day: 2,
+    });
+
+    expect(recipeRegistry.get('craft_plank')!.toolRequired).toBe('wooden_axe');
+  });
+});
diff --git a/server/src/industry/inventionRegistrar.ts b/server/src/industry/inventionRegistrar.ts
new file mode 100644
index 0000000..8043745
--- /dev/null
+++ b/server/src/industry/inventionRegistrar.ts
@@ -0,0 +1,48 @@
+import type { EntityId } from '@dflike/shared';
+import type { ItemRegistry } from './itemRegistry.js';
+import type { RecipeRegistry } from './recipeRegistry.js';
+import type { InventionTimeline } from './inventionTimeline.js';
+import type { RawInvention } from './inventionValidator.js';
+
+export interface RegisterInventionArgs {
+  raw: RawInvention;
+  itemId: string;
+  itemRegistry: ItemRegistry;
+  recipeRegistry: RecipeRegistry;
+  timeline: InventionTimeline;
+  inventorEntityId: EntityId;
+  inventorName: string;
+  tick: number;
+  day: number;
+}
+
+export function registerInvention(args: RegisterInventionArgs): boolean {
+  const { raw, itemId, itemRegistry, recipeRegistry, timeline, inventorEntityId, inventorName, tick, day } = args;
+
+  // Register item
+  itemRegistry.register({
+    id: itemId,
+    name: raw.name,
+    description: raw.description,
+    category: raw.category as 'resource' | 'tool' | 'material' | 'structure',
+    source: 'invented',
+    inventedBy: { entityId: inventorEntityId, name: inventorName, tick, day },
+  });
+
+  // Register recipe
+  const recipePrefix = raw.category === 'structure' ? 'build_' : 'craft_';
+  recipeRegistry.register({
+    id: `${recipePrefix}${itemId}`,
+    outputItemId: itemId,
+    outputQuantity: 1,
+    inputs: raw.inputs,
+    workshopType: raw.workshopType ?? undefined,
+    toolRequired: raw.toolRequired ?? undefined,
+    source: 'invented',
+  });
+
+  // Record in timeline
+  timeline.record({ itemId, inventorEntityId, inventorName, tick, day });
+
+  return true;
+}