Even for coding agents. MCP is the only unified interface INTO harnesses. This pattern has not struck yet for most, but will soon in the coming months given the MCP spec. MCP has been about models calling tools., it is about to become some form of inverse and MCP will be the only actual way to integrate into the models. Simple example is sending an event to the model (today models have to poll)... these coming updates will cement MCP as permanent infrastructure.