Most AI coding tutorials stop at "ask the agent to write code". This one is about giving the agent a tool it can call, an MCP server, so it can send and verify one-time codes while you're still building. I work at MyOTP.App and this uses our server, so read it with that in mind.
If you're on Claude Code, Claude Desktop, Cursor, Codex or anything else that speaks MCP, this takes about five minutes.
Why bother
When you ask an agent to "add phone verification" with no tool attached, it writes code against an SDK it half remembers. Sometimes that SDK doesn't exist in the version it picked. You find out at runtime.
With the MCP server attached, "send a code to my number" is a tool call. The agent sends a real message, you get a real SMS, and only then do you ask it to write the integration. The code comes after the proof.
