Saleor API + MCP vs Vendure

Saleor API + MCP

One GraphQL schema with 78 typed error-code enums and 464 marked deprecations. The MCP server can't create checkouts or orders.

Vendure

Full cart, coupon, shipping and payment flow in the GraphQL Shop API, with ErrorResult types an agent can branch on. No vendor-hosted API. Vendure Cloud is only partly available.

Saleor API + MCP

1. Pass the channel slug on product and checkout queries. Prices and availability are per channel
2. Send X-Saleor-API-URL and X-Saleor-Auth-Token on every MCP request, with a token holding MANAGE_PRODUCTS and MANAGE_ORDERS
3. Read the errors array in every mutation payload. A 200 response can still carry a CheckoutErrorCode
4. Keep queries under the 50,000 complexity cap and 100 items a page, and send at most 4 mutations per request
5. The 3.24 changelog removes the old dummy payment plugins, so test checkouts should use a payment app

Vendure

1. Keep the session token from the first Shop API response and send it on every call. It holds the active order
2. Check each mutation result's __typename and errorCode. Expected failures return 200 with an ErrorResult
3. Don't retry addItemToOrder blindly. Read the active order first, since a repeat adds the quantity again
4. For server-side work, enable api-key in authOptions.tokenMethod and give the key one role in one channel
5. Run 3.7.3 or later, and purge old job records, which may still hold session tokens