For years the standard advice was that ideas are cheap and execution is everything, so founders could share almost anything without risk. That advice assumed a competitor who read your post would need months of engineering to act on it. With agentic coding tools, a competitor can turn a publicly shared architecture, revenue picture, and feature description into a working rival in days, which is why Arvid Kahl argues that the old safety threshold for transparent sharing has collapsed in his analysis of the risk.
The practical point is not "stop building in public." It is that the default has flipped. You now need a deliberate filter on every draft rather than a vague feeling that transparency is good. Kahl frames the filter as a single question: is this interesting to follow, or easy to clone? That question is the seed of the test this article turns into a repeatable routine.
The second shift is legal as well as competitive. Information that is not generally known and has economic value from staying unknown can qualify as a trade secret, and that status is lost when the information is disclosed without restriction according to a trade secret primer for businesses. The World Intellectual Property Organization makes the same point: secrecy is a precondition, not a nice-to-have in its trade secret FAQ. A public post is the opposite of a restricted disclosure, so once it is out, you cannot walk it back into protection.



