VZU Insights · VZU primer · 2026-06-12
MCP, explained.
Model Context Protocol, in plain language. What it does, what it does not, and how VZU uses it inside Agentic OS.
The essay
MCP, explained.
Model Context Protocol (MCP) is a JSON-RPC standard for how an agent invokes an action. It is not an agent framework. It is not a workflow engine. It is the contract that lets an action advertise what it can do and lets an agent ask for the action to be performed. This is a primer on what MCP is, what it does, and what it does not.
The reason MCP matters is the integration math. Without a standard, every agent-to-action integration is bespoke. The agent vendor writes one. The action vendor writes another. The customer pays for both. With MCP, the action vendor writes one MCP server and every MCP-compatible agent can use it. The economics flip from N×M (every agent to every action) to N+M (every agent speaks MCP, every action speaks MCP).
An MCP server is, conceptually, three things: a list of actions (with name, description, input schema, output schema), a list of resources (data the action can read), and a list of prompts (pre-built sequences the agent can invoke). When an agent connects to an MCP server, it reads the action list, decides which action to call, calls it, gets the result, and continues reasoning.
The patterns that work in production: stateless actions with a single responsibility, structured inputs, structured outputs, fast response times, and explicit error semantics. The patterns that fail: stateful actions that hold long-running connections, actions that depend on user-specific context that the agent does not have, actions with ambiguous error responses, and actions that are too slow for an interactive agent loop.
The most common production failure is an action that takes 30 seconds to return. The agent times out. The user sees an error. The right answer is to make the action async — return a job ID immediately, let the agent poll. The second most common failure is an action that returns a 500 when the input is wrong. The right answer is to return a structured error with a code the agent can match on. The third most common failure is an action that does too much. The right answer is to break the action apart.
In the Netwit runtime, every system integration is an MCP server. PostMTA exposes a "send email" action. InboxGrove exposes a "classify email" action. ChartFlow exposes a "generate clinical note" action. TrackSphere exposes a "log field event" action. The agent composes them. The agent decides which to call, in what order, and what to do with the result. The audit trail records every call.
Disclosure
Dhiraj Chatpar is the founder of VZU. The VZU team wrote this essay. The runtime described is in production at a small number of operators. The benchmarks, where cited, are from internal testing or from operators who have given permission to publish.