I'm planning on starting a campaign of Waterdeep: Dragon Heist tomorrow, but it's looking like we may only have two players (plus me as DM) for it. The other published adventures I've used (Lost Mine of Phandelver and Storm King's Thunder) each say a recommended party size for them, which we haven't always had but helped me figure out how much I needed to adjust the included encounters when we had fewer players. But I can't find within Dragon Heist the party size that it's designed for. Due to it being more of an intrigue-based campaign than a hack-and-slash style, does it work just as well if you have two PCs or six?
While not stated explicitly, the norm still appears to be 5 players. However there are useful suggestions on the internet for balancing the module for different numbers of players. One such example is by a reddit poster who seems to have prepared explicit adjustments for various encounters: https://www.reddit.com/r/WaterdeepDragonHeist/comments/9ldz7k/scaling_for_waterdeep_dragon_heist/
With two players, you can also consider letting each player run a second character or a sidekick. https://media.wizards.com/2018/dnd/downloads/UA_Sidekicks.pdf