# Matched Capabilities, Different Behaviors: A Controlled Study of MCP and CLI Interfaces for Language Agents > Source: > Published: 2026-10-30 16:00:09+00:00 Language agents increasingly act through external tools and interactive environments, making the interface between the model and its executable capabilities part of the decision process. Model Context Protocol (MCP) and command-line interfaces (CLI) can expose the same semantic operations through ma