By special agreement, things are allowed which are not otherwise permitted.

Explanation

(English-origin maxim.) Parties may agree by special contract to terms that would not otherwise be permitted by default rules — private agreement can override directory law where no public right is invaded.

Where this applies

• Two business partners agree to a non-compete clause that would normally be unenforceable under default law, but because it was negotiated as a special term of their deal, the court upholds it.
• A landlord and tenant agree that the tenant may keep livestock on a residential property, overriding the standard lease prohibition, because their special agreement permits it.
• Parties to a construction contract agree to a dispute resolution process that differs from the default court procedure, and the court honors their special agreement.