Can you use an EA on a prop firm account?

There is no industry standard here, which is exactly why the question keeps being asked. Two firms with near-identical drawdown rules can take opposite positions on automation, and the policy is frequently buried in the terms rather than stated on the sales page.

The specific restrictions worth checking before paying an evaluation fee are: whether EAs are permitted at all, whether they are permitted during evaluation as well as after funding, whether high-frequency or latency-sensitive strategies are excluded, whether trading through news is allowed, and whether the same strategy may run on more than one account you hold.

That last one catches people running a bot across several funded accounts. Many firms treat identical trade sequences across accounts as copy trading regardless of intent, and the consequence is usually termination of all of them rather than one.

Configuring a bot for prop firm rules

The rules should drive the settings, not the other way around. A 1.5% per-trade default is sensible against a 10% maximum drawdown and reckless against a 4% daily limit, and the difference between a static and a trailing drawdown changes what the account can survive more than any strategy parameter.

Set the bot's own daily loss lockdown below the firm's limit rather than equal to it. The trade that reaches the threshold will slip, and equality leaves nothing to absorb it — this is the specific mechanism behind most surprise breaches. See prop firm account failed.

Work out the numbers before starting with the prop firm drawdown calculator, and read prop firm rules explained for what each rule actually measures.