An agent whose "arrived" test is stricter than its steering goal parks short of the goal for good

Fact

When the check that says "there, act now" asks for more than the goal the movement code steers toward (a height as well as a horizontal distance, say), the agent stops inside its steering radius, believes it has arrived, and never satisfies the check. A stuck detector that only measures horizontal progress never fires either, because the agent is not trying to move.

Why it matters

Nothing errors and nothing looks stuck: the agent stands still, steering reports "reached", and the task waits on whatever fallback timeout exists. A per-step fallback ("give up after 15 s, do one step") turns into a 15 s stall per step. The same blind spot hides an agent rising in place under a ceiling: it is within horizontal reach, so it is not "moving", so it is never "stuck".

How to apply

• Derive both from one predicate: whatever makes "near" false must also make the steering goal ask for that movement (e.g. flyTo: up > 2 || tooLow).
• Measure progress on every axis the goal asks for; count "wanting to rise" as moving, and when stuck with no horizontal error, step sideways in a direction that changes over time.
• Reset a give-up timer only on actually arriving, not on each step done via the fallback, so one give-up covers the whole stretch away.
• Reproduce under load (a background-priority run) — slow ticks expose it.