What happens in a bartering system when a resource is plentiful but cannot be paid for?
Tribe A will not necessarily sever barter with tribe B. This has to do with Production Possibility Frontier and related concepts such as specialization &amp; utility.

Tribe A's production of bricks could certainly press tribe B to agree to a bricks/fish exchange rate that is more convenient to tribe A than it was prior to the latter's invention of tools to create bricks.

In an extreme scenario, tribe A's bricks might be of better quality and much cheaper than tribe B's bricks. That might render A unlikelier to maintain barter with tribe B. If so, tribe B might want to consider fish substitutes such as hunting, veganism, veganism's closest alternative (i.e. cannibalism), acuphagia (of A's new tools), or outright eating bricks.