StopCondition

First-class loop stop conditions (invariant I-7). The SDK manages the loop; consumers express completion as a StopCondition passed to the agent constructor or generateText.

Built-ins:

• stepCountIs — stop after N completed steps. Default stepCountIs(20) so any agent without explicit stopWhen still terminates.

• hasToolCall — stop the moment a specific tool is called.

• anyOf — short-circuit OR over multiple conditions (matches v6's array form).

Custom: implement StopCondition directly. Receives a snapshot of the loop state on every check.