Technical pre-order checks that prevent duplicate positions, wrong size, stale signals and accidental live execution.
In plain English
This guide is about preventing a technically functioning bot from taking an unintended action. Checks should run immediately before the important action, not only at startup.
kill switchposition checksize checkfail closed
Validation is not the same as a profitable strategy
Risk checks protect the system from operational mistakes. They cannot make a losing strategy profitable, but they can stop some avoidable failures.
Pre-order gate
def can_submit(event, state, cfg):
if cfg.environment != "demo" and not cfg.live_enabled:
return False, "live_disabled"
if event.age_seconds > cfg.max_signal_age:
return False, "stale_signal"
if state.has_open_position(event.symbol):
return False, "position_exists"
if event.size > cfg.max_size:
return False, "size_limit"
if state.seen(event.event_id):
return False, "duplicate_event"
return True, "ok"Check position state immediately before submission
Do not rely only on a position snapshot from several seconds ago. Another process, manual trade or previous delayed order may have changed the account.
Stale-signal protection
A webhook arriving late should not automatically become a current trade. Include a signal timestamp and define the maximum acceptable age.
Practical lesson: a “wait because another position is already open” guard may reduce trade count, but it is often doing exactly what it was designed to do: preventing overlapping exposure.
Before you rely on this in production
- Demo/paper behavior is proven first.
- Size and current position are checked immediately before action.
- A kill switch blocks new actions.
- Uncertain timeouts do not cause blind duplicates.