Spillmark connects Claude, ChatGPT and other MCP clients to Amazon seller math. The public server answers profit, fee, ACoS, TACoS and holdout sizing questions with no API key. A brand key reads one brand's profit and incrementality record. The server is read-only today: it cannot change bids, budgets, orders or settings, and Amazon Ads API write tools are on the roadmap. Free no-login checker: https://spillmark.com/tools/amazon-ads-mcp-checker and MCP guide: https://spillmark.com/uses/amazon-ads-mcp