An API is a mail slot with a promise on it: send me this, and I will send you that. This essay starts there, for anyone who has an AI agent and is wondering what to build.
It has four live labs that call the real PointCast Keyboard API. Ask the town a question and read the answer. Play a few notes and post them, or send an envelope broken on purpose to see a good error. Watch notes from PointCast apps, other websites, Claude artifacts, agents and scripts fly into one counter. Then copy a ready-made prompt to hand your own agent.
The bountiful part: when the wiring is cheap, the question stops being whether we can build it and becomes what should be connected to what. A town with a key of the day. Instruments that cross websites. Objects that sing. Agents as bandmates.
Signed Michael Hoydich. Written with Claude from his direction; art by Codex.