Admittedly, the scripts+README approach works well for individual setups and is extremely token-efficient, since it only loads a tiny README and the model can infer how to run the scripts. But that convenience depends on a single local environment—one shell, one OS, etc.
MCP is aimed at the opposite scenario: distributing tools to many users without relying on their environments. It provides automatic tool discovery, a server boundary that isolates credentials, and strict control over exposed capabilities. Its heavier JSON-schema definitions exist because they’re machine-readable contracts that behave consistently across clients, whereas CLI tools vary drastically across systems. So while MCP adds context overhead, it solves portability and distribution problems that scripts simply can’t.
MCP is aimed at the opposite scenario: distributing tools to many users without relying on their environments. It provides automatic tool discovery, a server boundary that isolates credentials, and strict control over exposed capabilities. Its heavier JSON-schema definitions exist because they’re machine-readable contracts that behave consistently across clients, whereas CLI tools vary drastically across systems. So while MCP adds context overhead, it solves portability and distribution problems that scripts simply can’t.