What an Expert Advisor actually does

An Expert Advisor, or EA, receives price and account information from MetaTrader 5. Its rules evaluate that information, decide whether a setup exists, calculate position size, and send or manage orders according to its programming.

A typical flow is: data arrives, a new-bar or tick condition is checked, entry filters are evaluated, risk is calculated, an order is sent, and stops or exits are managed while the trade is open.

Automation is useful for consistency. It can monitor a market without fatigue, apply the same filters every time, calculate size, and record decisions. It can also enforce rules that a human might ignore after a loss or during a fast market.

That consistency is only valuable when the rules are sensible and the execution environment is working. Automation makes a process repeatable; it does not make a weak process profitable.

An EA cannot guarantee profit, remove slippage, prevent a broker outage, or know how a future market regime will behave. A stop order can fill differently from its requested price, especially during a gap or volatile release.

The person running the EA remains responsible for account selection, risk settings, broker and prop-firm rules, and monitoring. Read the documentation and understand the failure modes before going live.