Stephen Tu, on 2015-February-16, 22:54, said:
It's pretty much forced into this by system, this is a common scenario among 2/1 practitioners. If not allowing 1nt with GF strength, and 2♥ promise 5, and 2♦ promise 4, you are endplayed into 2♣. Not a thing of beauty but it usually works out OK as you are going to support a major next anyway. So I guess "biddable clubs or 3433"? It's reasonable for descriptive purposes and GIB's simulations to usually presume better clubs than this, sometimes you just have holes in your system. Just like GIB should assume 1h-1nt-2c is 3+ even though one could be 4522.
Or 2434 (or maybe 1444) with 4 small clubs. There's no reason to go out of the way to include "biddable" which in GIBberish means 5, or 4 good ones. 2
♣ only promises 3+, although follow-up bids can show that you actually have more.