The framing of “what not to tell your contractor” usually comes from residential horror stories, but on a commercial project the dynamic is different — you want maximum transparency with your GC, not less. The real question is how to communicate effectively, not what to hide.
That said, there are things commercial owners shouldn’t communicate carelessly: don’t share your absolute maximum budget before pricing comes in (it removes incentive to value engineer), don’t commit to a move-in date publicly before the schedule is validated, and don’t bypass the GC to direct subcontractors yourself (it breaks the chain of accountability and creates change order disputes).
What you should tell your GC: your real priorities (cost vs. schedule vs. quality vs. flexibility), your business drivers behind the project, and any constraints you know about. The best commercial GC relationships are built on honest two-way communication. Darby works this way with every client.
