With this Agreement, the Autonomous Communities were recognized the right to participate in the formation of the State will before the European institutions (the so-called “upstream phase” of the process), since until then the Autonomous Communities only participated in the implementation of Community law (that is, the “downstream phase” of it).

On December 9, 2004, the CARUE adopted the Agreement that definitively opened to the Autonomous Communities participation in the four formations of the Council of the European Union whose activity is most significantly related to their internal competences, in particular the Councils of Ministers of: Employment, Social Policy, Health and Consumers; Agriculture and Fisheries; Environment; and Education, Youth and Culture. The system of autonomous representation is carried out through the incorporation into the Spanish Delegation of a member, with the rank of Councillor, or member of a Council of an autonomous Government, who represents all the Communities in matters that affect their competences. The plenary session of the Sectoral Conferences concerned with the issues to be dealt with appoints the autonomous representative, ensuring both stability (each Community covering at least one semester) and succession of the representatives proposed by the different Autonomous Communities. The designated autonomous representative assumes the agreement with the General Administration of the State, and undertakes to make available to the rest of the Autonomous Communities the complete documentation on the matter, to keep them regularly informed about the negotiations, and to agree on a common position with the other Autonomous Communities affected. The autonomous representative is a full member of the Spanish Delegation for all purposes, being able to request the use of the word when issues affecting the autonomous competences are discussed and there is a common autonomous position.

The agreement approved in the CARUE of December 9, 2004 has subsequently been modified on three occasions: the first modification took place in the meeting of the CARUE of July 2, 2009, in which the autonomous participation was extended to a fifth formation, that of Competition-topics of consumption, since, although the autonomous participation already existed for topics of consumption since the Agreement of 2004, in practice these topics were debated in the Competitiveness Council; the second modification was agreed in the meeting of the CARUE of April 15, 2010, expanding the autonomous participation to the formation of the Council of Competitiveness, These modifications were published in the B.O.E. of 11 August 2011.

In order to facilitate the process of autonomous participation, at the CARUE meeting held on December 12, 2006, a Guide of Good Practices was agreed that specifies the system of transmission of information to the Autonomous Communities, defines the criteria used for the appointment of the autonomous representative in the Councils of Ministers, and regulates coordination between the Autonomous Communities, and between them and the Government of Spain.