BigCommerce API + MCP vs Swell

BigCommerce API + MCP

Published rate limits per plan, with X-Rate-Limit-Time-Reset-Ms on every 429. Storefront MCP is beta, switched on per store, has no back-office tools and documents no tool annotations.

Swell

Live /:models schema with field types and descriptions for every store. One full-access secret key per environment, with no scoped or read-only key.

BigCommerce API + MCP

1. Give the agent a store-level API account with only the scopes the task needs, and delete it when done
2. On a 429, wait X-Rate-Limit-Time-Reset-Ms before retrying
3. Expect up to 10 minutes after a store owner enables the MCP before the URL answers
4. The MCP stops at a checkout URL. Payment happens in the shopper's browser
5. Point a coding agent at the docs MCP at https://docs.bigcommerce.com/_mcp/server

Swell

1. Call GET /:models once and cache it. It's the ground truth for custom fields
2. Check result.errors after every write. A failed validation still returns 200
3. Use $set to replace an array. A plain PUT merges arrays by element id and never shrinks them
4. Use an sk_test_ key while testing. A bare sk_ prefix is live
5. Keep expand and include small. Each level past the first three points adds rate-limit weight