Prop-firm EA rules: how to run an EA without breaching drawdown limits

Most prop firms kill EAs not because the strategy is bad, but because the risk management is static. You have to understand that these firms are selling a mathematical edge against your emotional and mechanical discipline. If your EA is designed for a live account with a 20% drawdown tolerance, it will almost certainly blow a 10% max drawdown limit on a prop challenge within weeks.

Here are the common hurdles that break automated systems:
- Daily loss limits: If your EA doesn't have a hard equity-based cutoff, a single bad session can end your account.
- Equity drawdown: Firms track open trade loss, not just closed trades, which ruins martingale or grid systems.
- Consistency rules: Some platforms flag you if one trade makes up a huge chunk of your profit, forcing you to trade smaller sizes.
- News restrictions: Trading during high-impact news often breaks the rules, requiring an EA that can read economic calendars via API.

To survive, you need to decouple your strategy from your risk engine. Don't let the EA manage the account risk directly. Use a separate trade manager or a custom wrapper that sits between the EA and the broker terminal. This middle layer should enforce a hard daily stop-loss in dollars, regardless of what the EA wants to do. If the account equity hits that number, the wrapper should close all positions and disable the EA for the day.

Also, stop using fixed lot sizes. You need a dynamic position sizing logic that shrinks as you get closer to the daily drawdown limit. If you have a 5% daily limit, don't risk 1% per trade. Scale it down to 0.25% or 0.5% so you have room to actually survive a bad morning. Are you coding your own risk management layer, or are you still relying on the EA's internal settings?