In commercial lease space, is it the Tenants responsibility to bring the property up to code or the Landlords?

Hi Michael,
This depends on if you have a Full Service Lease, or a Net Lease. You must read the language and it will spell out what you are responsible for ans what the Landlord is responsible for. Usually office buildings are full service but not always. If you need further assistance I would be glad to review it and render my opinion, but I am not an attorney or attempting to render legal advice, only real estate savvy.

You would workout details before signing lease and add language to lease before signing lease this way there are no MISTAKES

It is the Landlord's responsibility to be sure it gets done, and then if the lease is NNN the landlord will pass this expense through to the tenant.
RW.

The teant must ensure who is responsible. I would never take a lease without the building or space meeting code in addition to having the building owner supply needed alterations to meet my needs (this includes all mechanicals).
Unless the rent is far below the market value and or you are receiving free months to accomodate the expense of improvements it isn't worth doing. Remember you're leasing not buying. I know many a leasor who insists on making sure the building or space is right and the tenant is comfortable when a 3 or longer year lease is desired with renewal options. They see this expense and flexibility as a sound investment to a sucessfull tenant and lease. Flexibility and team work between the owner and tenant yeilds many rewards for both parties.
Watch out for those who make unreasonable demands upon tenants in that they only want your money and the chance to get a judgement against you. Its a whole new world out thwere and traditional financial thought is obsolete. Know whats best for your business and do it even if it means relocating to another state.
Good Luck.

Aside from the aspects of NNN vs Gross Lease terms there is the aspect of the lease being breached by the space not being up to code. If the City shuts down the business due to code violations, the lease may become voidable. The resolution of this legal problem is one a lawyer will need to answer.

It depends. The Landlord is typically responsible for keeping the Subject up to code, but it all depends on the language contained within the executed lease. More importantly, if it is a new lease certificates of occupancy will be required for any build out before the tenant can occupy the space.