Running an EA on a prop-firm challenge: the rules to code in, not remember

Daily loss limits, maximum drawdown, news restrictions and weekend holding: how to turn prop-firm challenge rules into hard EA inputs and an equity guard.

Rules break accounts, not just losses

Most failed prop-firm challenges don't fail on a bad strategy. They fail on a rule: a daily loss limit touched during a spike, a position held over the weekend, or a trade opened inside a restricted news window. An EA follows code, not the rulebook, so the rules have to be inputs.

The limits to hard-code

Daily loss limit, measured the way the firm measures it (balance or equity, and at what server time the day resets).
Maximum overall drawdown: static or trailing, depending on the firm.
Risk per trade as a % of equity, well below the daily limit.
News window: no entries (and sometimes no open positions) around high-impact releases.
Weekend / overnight rule: close before Friday's close if holding is not allowed.

Belt and braces: an equity guard

Run an account-level equity guard, such as Vidette, alongside the strategy EA. If the strategy misbehaves, the guard closes positions and stops trading at the threshold you set. Set it a margin inside the firm's limit, because slippage can carry a close past the exact number.

Test the rules, not just the strategy

Backtest on real ticks and check the report for the worst day, not just the maximum drawdown. If the worst historical day breaches the daily limit, the EA will eventually breach it live.

Questions

Can an EA guarantee I pass?: No. Rules can be enforced in code, but results can't be guaranteed. Anyone promising a guaranteed pass is selling hope.
Balance or equity based?: Check your firm's rules: many measure daily loss on equity, including floating losses.

Put it into practice. Algo Dispensary drops VERUM-screened MT5 EAs every weekday and runs a weekly testing challenge. Members get Vidette, our equity-guard EA, free.

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