Should I disclose to clients that I used AI to write the proposal?

Not legally required in most B2B sales, but the norm is converging on the Grammarly standard: don't disclose tool-assisted writing, do disclose tool-authored content if asked. Disclose for government/regulated procurement, legal/medical work, and when the client asks directly — most clients respect "I directed an AI to draft from our discovery call, then edited it."