This isn't a zero-sum game or a choice of one over the other. They solve different layers of the developer experience: MCP provides a standardized, portable interface for external data/tools (the infrastructure), while Skills offer project-specific, high-level behavioral context (the orchestration). A robust workflow uses MCP to ensure tool reliability and Skills to define when and how to deploy those tools.

MCP is just CLI wrapped in boxes.

CLI is the same API in more concise format. At minimum, the same amount of context overhead exist for MCP, but most of the time more because the boxes have size.

CLI can be secure, AWS CLI is doing just fine. You can also play simple tricks to hide secret in a daemon or run them remotely, and all of them are still smaller than a MCP.