For an API partner acting for your brokerage (a token carrying the partner claim, with broker_submit) on a submission that partner created. Returns a one-time Hedge portal sign-in URL for producer_email that opens this quote: landing is bind (the bind checklist), quote (terms still incomplete, or the quote binds on the carrier's own portal) or status (the lane is binding or bound). The URL expires after about 120 seconds and works once. It is a credential: redirect the signed-in user to it immediately and never store, email or log it. The first redemption makes the partner's file a normal Hedge file.

producer_email must be an active portal user of your brokerage, or a producer on file with your brokerage (Hedge then creates their portal account; no email is sent). return_url must be https on an origin Hedge approved for the partner; the portal offers it as the way back. Any other caller, or a submission the partner did not create, gets 404.