Prefer Monthly Expiry
Setting key
mechanical_prefer_monthly_expiry
Default
ON
What it does
When ON, the mechanical engine prefers standard monthly option expirations (3rd Friday of the month) over weekly expirations within the DTE window. Weeklies have narrower open interest and wider bid-ask spreads. Monthlies are the deep-liquid cycles tastytrade research targets. If no monthly expiry exists in the DTE window, the bot falls back to the full list of eligible expiries.
When to change it
Turn OFF only if your underlyings lack meaningful monthly cycles and you need to use weeklies.
Safe range
ON or OFF.
Example
DTE window is 30 to 65. July 18 (standard monthly) falls in that window. The bot prefers July 18 over July 11 or July 25 (weeklies) when prefer_monthly_expiry is ON.