Anthropic's Model Context Protocol, announced in 2024, is sometimes presented as a replacement for REST API. That is inaccurate. An API is a fixed contract for connecting two systems: a specific endpoint and a specific response schema defined in advance by a person for a specific task. MCP solves a different problem: giving an LLM agent a way to discover available tools and decide which one to use without manually defining every scenario.
A developer who substitutes one for the other instead of using both for their intended purposes ends up with either an agent without predictable boundaries (pure MCP where strict integration with an accounting system is needed) or a rigid script where the client needs conversational flexibility.
In KT.Team integration projects, this separation is established during architecture design: MCP is used where the agent must navigate available tools independently (RAG search, CRM, calendar), while API and LLM & Security Gateway are used where a fixed, auditable contract with 1C, Bitrix, or a payment provider is required.