Why does this "kind" cause a problem?

I’ve worked through this problem, thanks to a lot of folks. I’m pleased that I was doing some pieces correctly myself but I was also confused by why they were not working.

By a systematic process of eliminating chunks of my program, one at a time, I managed to locate the issue. In the following snippet, removing the-

a barrel is a kind of thing.
an old barrel is a barrel.
the old barrel is undescribed.

makes it possible to pick up the barrel and put it in the barrow by just typing get barrel. I could just go on my merry way but that’s not going to help me understand.

I’m hoping someone can shed some light on the issue.

A barrel is a kind of thing.
The old barrel is a barrel.
The old barrel is undescribed.
The old barrel is in the front garden.
The description of the old barrel is "This is an old and water-logged barrel barely held together with rusted bands. It looks heavy and none too sturdy."

After taking the old barrel when the rusty barrow is not in the front garden for the first time:
	say "You lift the barrel but it is so heavy and water logged that you drop it again. Dropping it like that again will surely destroy the barrel. In fact it looks ready to fall apart at any moment even if you try to roll it.";
		now the old barrel is in the front garden.
	
After taking the old barrel when the rusty barrow is not in the front garden:
	say "Lifting the barrel a second time you drop it almost immediately, the steel banding comes free and slices through your foot. You die.";
				end the story.

After taking the old barrel when the rusty barrow is in the front garden:
	say "You lift the barrel and put it in the wheelbarrow.";
	now the old barrel is in the rusty barrow.

Instead of taking the old barrel when the old barrel is in the wheelbarrow:
	say "The old barrel already is where it belongs."

I think this is my own problem. It seems like, if you make an object undescribed, and you examine a container it is in, it will not be read out because it is undescribed.

Does that seem correct?

Yes. “Undescribed” does several somewhat related things, and that’s one of them.