A signed offer is evidence of a proposed role, not the permission itself. Confirm the authorized start point before undertaking US professional services.
Make the start date depend on the immigration result
TN analysis begins with a defined professional engagement, not the convenience of a travel calendar. For this question, focus on whether the required classification has been obtained before US work begins. Use a signed offer to support the request, but distinguish an employment start condition from authority to perform US duties.
Read the governing instruction together with the actual agreement, identity record, financial material, or corporate record that bears on the point. A short summary can organize the evidence, but it cannot cure a missing legal element. The answer turns on the documented arrangement, not on a label chosen for convenience.
Set a contingency start date and tell the employer how a delayed decision will be handled. Keep copies that show dates, authorship, and the connection between the claimed plan and the records. Where a rule has a time limit or a filing window, calculate it from the controlling event rather than from an informal target date.
Hypothetical example: a software analyst signs an offer on Monday and is asked to join a US project call as a working team member on Tuesday. That example would call for a fact-specific review of the documents and timing before anyone relies on it. A remote consultation can help identify questions for the appropriate employer, business, or regulated adviser; it does not guarantee admission, a visa, or approval.