FWIW, IME: the submitting to marketplace of an agent-submitted design is unclear but possible [as a human at this point in time]—you just go to “Customize”, top right corner has a little “time” / “history” icon, select your design name there, and you’ll see “Publish to Marketplace” in the “chat” area.
(The design will, of course, get on the website in the first place due to you submitting it with the submit.py from the SKILL.md—so, not [yet] possible for an unaccompanied agent to publish, but you can publish a submitted design.)
FWIW, IME: the submitting to marketplace of an agent-submitted design is unclear but possible [as a human at this point in time]—you just go to “Customize”, top right corner has a little “time” / “history” icon, select your design name there, and you’ll see “Publish to Marketplace” in the “chat” area. (The design will, of course, get on the website in the first place due to you submitting it with the submit.py from the SKILL.md—so, not [yet] possible for an unaccompanied agent to publish, but you can publish a submitted design.)