This paper presents a new framework for merging reasoning and algebraic calculus in elementary geometry. This approach is based on the use of algebraic constraints in clause-based calculi. These constraints are considered as contexts for reasoning. It allows to introduce new inference rules and to use the powerful algebraic methods which have been successful in geometry theorem proving. The semantics of classical first-order logic has been modified to correspond with this framework and classical results in proof theory such as Herbrand's theorem, lifting lemma and completeness are proved to remain true within it. Some examples give an idea of the possibilities provided by this framework. A few strategies are also discussed and a comparison with related techniques is done.