Save a Watch to your key (the paid step)

Saves a Watch into a slot: a paid slot at the published Watch rate per saved Watch per month (GET /api/tariff, units[watch].price, which also serves units[watch].opening_offer), or, while the opening offer is open, an opening slot on a verified email address. Your first five Watches are on us while we open the doors. Save up to 5 Watches at no charge through December 31, 2026, one allowance per verified email address. No card is needed to start. After that a Watch is $20 a month, and only if you choose to keep it. Self-issue a key (POST /api/keys, free, instant), then confirm an email address for it: POST /api/keys/verify with {"email"} and your key, and press the button in the email we send. Your next saves go into the opening slots. Paid slots are used first. With no free slot of either kind the answer is 402 with the next step, and nothing is saved or charged. Pass watchId to edit a saved Watch: a new version, no extra charge. Same content as the MCP tool save_watch. Buying steps: GET /api/tariff, units[watch].how_to_buy.