THE MODEL CONTEXT PROTOCOL (MCP) AND TOOL STANDARDS

EXAMPLES Example 1: One server, many clients. A company builds a single MCP server that exposes its internal customer database, with tools to look up customers and list recent orders, and with read-only access. The same server is plugged into a chat assistant from one vendor, into a different vendor's model used by the support team, and into a custom in-house agent built by the analytics team. No integration code is rewritten for any of them, because all three speak the same protocol. When the database team improves the lookup tool, all three agents benefit at once. Example 2: Client, server, and transport. A developer's coding assistant, the host, contains an MCP client connected to a code-hosting-site server. In the first setup the client launches the server on the developer's laptop and communicates over stdio to list open pull requests, which are proposed code changes waiting for review. In the second setup the company runs the server centrally, and every developer's client reaches it over a network transport after logging in. The tools are the same in both cases; only the transport differs. Example 3: The interoperability benefit. A developer builds one MCP server for the company's ticketing system with tools such as create_ticket, get_ticket, and add_comment. Rather than writing separate custom integrations for the support agent, the sales agent, and the engineering agent, the team connects all three to the one server. Months later the ticketing vendor changes its API, and the developer updates the single server instead of three integrations. Example 4: The ecosystem trend. In November 2024 the standard was a proposal from a single company. By 2026, independent trackers reported thousands of public servers, though counts vary by source and a governance move to a vendor-neutral foundation in December 2025. A harness engineer reading these facts should conclude that learning MCP is a durable skill, while also remembering to verify current numbers and specification versions before quoting them in a report.