Starts a post-purchase recall watch on every product in a checkout that has been handed to the store to pay, once the person (or an agent authorised to accept on their behalf) has agreed to the current consent statement. RoboTrunk re-checks each watched product whenever a regulator publishes a new notice naming its brand; a match only ever flags with the regulator's own citation and never changes, cancels or delays the purchase. An item not matched to a listed product is watched by its checkout name, not refused; each product says watched_by "product" or "name". The full consent statement, version recall-watch-consent-v1: "RoboTrunk will watch the products in this purchase for a recall. What is watched: each product bought through this checkout hand-off, re-checked whenever a regulator publishes a new notice naming its brand. What is stored: the product and its title, the channel chosen to be told (poll, an agent callback URL, or a person's email address), and, only for a channel that is switched on, that URL or address; never a name, a postal address or payment details. Channels: an agent can always poll get_recall_watch for the result; a callback URL is used only when RoboTrunk has switched callbacks on; a person's email is used only when RoboTrunk has switched email on, the person consents under the Australian Spam Act, and the address holder confirms it by a link sent to that address. Frequency cap: at most three messages a day on one channel, and at most one email a day to one address, several alerts combined into one. How to stop: call stop_recall_watch at any time, or use the one-click stop link in an email; stopping is instant and permanent, and removes the stored channel data. This watch never changes, cancels, blocks or delays the purchase it watches; a recall only ever flags with its regulator citation." channels is optional: leave it out for the poll-only watch every purchase gets, and a channels value that cannot be read is left out the same way, with the answer saying poll was used. One watch per checkout: a second call returns the existing watch unchanged, and a stopped watch cannot be restarted. Use it after complete_checkout; keep the watch_token it returns (shown once) for get_recall_watch and stop_recall_watch. Error recovery: consent_required means show the person the statement above and call again with it; invalid_request names the field to fix; channel_not_available means retry with channels left out (poll only); checkout_not_handed_off means call complete_checkout first; checkout_ended means there is nothing to watch; watch_stopped means this checkout's watch was stopped and cannot restart; product_not_resolved means no item could be matched or named; use check_product; checkout_too_large means more than 50 different products; forbidden, not_found or checkout_not_found means that checkout cannot be read here, so send checkout_id exactly as an earlier answer returned it; continuation_not_found means that reference is unknown or expired, so call create_checkout again; rate_limited means wait and retry; service_unavailable means try again later; watch_failed (or any other unexpected error): retry once, then call submit_feedback. Next: get_recall_watch to poll for alerts. Full guide: get_tool_guide or /agent/tools.json#watch_recalls Example call: {"checkout_id":"mcp1_c_examplereferencevaluehere0000000000000","consent":{"given_by":"person","statement_version":"recall-watch-consent-v1"},"channels":[{"kind":"poll"}]}