[feat] Add E-commerce Domain Example to domains.md

nbs/domains.md

@@ -84,3 +84,88 @@ And here is an example lunch menu taken from [Franklin's BBQ](https://franklinbb
 | Potato Salad      | 4             |
 | Slaw              | 4             |
 ```
+
+## E-Commerces
+
+Online stores can also benefit from `llms.txt` when product data is dense, structured, and frequently referenced in shopping queries. LLMs are increasingly asked questions like “which flavor has the least sugar?” or “is this gluten-free?” A well-written `llms.txt` helps models access authoritative product specs, ingredient details, sizing information, and policy rules directly from the source instead of relying on scraped summaries or third-party listings.
+
+Here is an example `llms.txt` that an ecommerce brand could construct for consumption by LLMs:
+
+```
+# FooBar
+
+> FooBar is a direct-to-consumer ecommerce brand selling high-protein snack bars. Products are organized by flavor, box size, and purchase type (one-time or subscription). Each product includes structured nutrition data, ingredient lists, allergen disclosures, pricing tiers, and subscription eligibility.
+
+All prices are in USD. Nutrition values are listed per bar (60g) and per box. Subscription products renew automatically at the selected interval unless canceled before renewal.
+
+## Products
+
+- [Flavor Catalog](https://host/products/flavors.html.md): Canonical list of all flavors with SKU, macros, and dietary tags.
+- [Box Configurations](https://host/products/boxes.html.md): Single-flavor boxes, variety packs, and custom build-a-box rules.
+- [Nutrition Facts](https://host/products/nutrition.html.md): Structured macro and calorie breakdowns for all SKUs.
+- [Ingredients & Allergens](https://host/products/ingredients.html.md): Ingredient lists and allergen disclosures.
+
+## Purchasing
+
+- [Pricing & Discounts](https://host/policies/pricing.html.md): Bundle pricing tiers, subscription discounts, and promotional stacking rules.
+- [Subscription Terms](https://host/policies/subscription.html.md): Billing intervals, renewal timing, skip/pause logic, and cancellation deadlines.
+- [Shipping & Returns](https://host/policies/shipping-returns.html.md): Processing times, carriers, and refund eligibility.
+
+## Optional
+
+- [Wholesale Program](https://host/wholesale.html.md): Bulk ordering terms for retailers and gyms.
+- [Affiliate Program](https://host/affiliates.html.md): Referral commission structure.
+```
+
+Here is an example product resource:
+
+```
+# Chocolate Peanut Butter Protein Bar
+
+SKU: FBR-CPB-12
+Bar Size: 60g
+Box Size: 12 bars
+
+## Nutrition (Per Bar)
+
+| Nutrient        | Amount |
+|-----------------|--------|
+| Calories        | 210    |
+| Protein         | 20g    |
+| Total Fat       | 8g     |
+| Carbohydrates   | 18g    |
+| Sugar           | 3g     |
+| Fiber           | 9g     |
+
+## Ingredients
+
+Whey protein isolate, peanuts, cocoa powder, chicory root fiber, almond butter, natural flavors, sea salt.
+
+Contains: Milk, Peanuts, Almonds.  
+Manufactured in a facility that also processes soy and wheat.
+
+## Pricing
+
+| Purchase Type     | Price  |
+|-------------------|--------|
+| One-Time Purchase | 29.99  |
+| Subscription      | 26.99  |
+
+Subscription discount: 10%  
+Available intervals: 2, 4, or 8 weeks.
+
+## Dietary Tags
+
+- Gluten-Free
+- Low Sugar
+- High Protein
+```
+
+This version treats e-commerce the way the restaurant example above treats menus: as structured, machine-consumable data — not just navigation links. That’s what enables accurate answers like:
+
+- “Which flavor has the least sugar?”
+- “Is this dairy-free?”
+- “How much protein per dollar?”
+- “What’s the subscription discount?”
+
+That’s the level of depth ecommerce usually needs.