International agreements may vary depending on the purpose, the number of parties, the legal functions and roles of the parties, their nature, in writing or orally, the approval procedures. An agreement between states on the establishment, operation and completion of a project is an international agreement. In this context, the VCLT applies to AI. The CEW is an agreement between states that are subject to international law. State commitments to the project, the amount of their contribution to the project and other agreed issues are taking place in the SLFs. Ai`s role is to make the project an international outcome, reducing states` commitments to the project`s success to an internationally binding document. Under the CEW, companies that invest have the right to rely on a second agreement in which states participate, with the exception of W`s private agreements in which they are the only ones to participate. The TANAP pipeline passes through 20 provinces of Turkey – Ardahan, Kars, Erzurum, Erzincan, Bayburt, Gom`hane, Giresun , Sivas, Yozgat, Kérehir , Kérkkale, Ankara, Eskiéhir, Bilecik, Kotahya, Bursa, Balikesir, `anakkale, Tek. The pipeline will start from the Sangachal terminal and in the Azerbaijan region, it will be the extension of the current South Caucasus pipeline (SCPx). From the arrival point of SCPx, which is in Erzurum, it continues to Eskishehir, where it is discharged of 6bcm of gas which belongs to Turkish buyers.
From the border between Turkey and Greece, we pass through Greece, Albania and ends in Italy.  The exact route of the pipeline is unclear. However, it was announced that one branch of Turkey would go to Greece and the other to Bulgaria.  It would be connected to Trans Adriatic Pipeline.   In March 2015, the Turkish government stated that a branch from Greece to Hungary would also be considered, via Macedonia and Serbia.  Agreements differ on subjects in politics, military, commercial, scientific, cultural and judicial. It is possible that an agreement will be reached on more than one subject. A military agreement to curb trade rules can be an example.
In order to assess the completion of TANAP agreements, cases that constitute a reason for termination under VCLT should be considered.