Agents sometimes pin down random behaviors with tests.

Like the Lilliputians pinning down Gulliver.

An agent comes up with a hacky workaround to a problem.

It pins that behavior with tests.

Later agents assume the tests are important and put in even more complication to achieve their goal while not breaking the tests.

Over time it becomes an impossible thicket of random tests pinning accidental behavior.

Tests pin things and the assumption is the things being pinned are intentional.

Tests used to be a pain in the butt to write, so humans only put them there if they were important.

Now agents add tests to every damn thing, and the structure becomes a liability.

They embed misunderstandings structurally, so other agents would have to swim upstream to counteract them.

So you're left with things where weeks later you go "wait, what?" and realize how much structure has been built up with the wrong assumptions.