The contract, as a central category of Private Law, can be understood as the agreement of wills aimed at the creation, modification or extinction of legal relationships of a patrimonial nature. It is a legal act in the broad sense, whose binding force derives from the convergence of free and conscious wills, oriented to the production of legal effects.

With technological advancement and the digitalization of economic and social relations, there is a progressive migration of these manifestations of will to the virtual environment. Thus, the digital contract arises, understood as the legal transaction entered into by electronic means, in which the formation of the bond takes place through the transmission of data between digital platforms and users.

Although inserted in a new environment, digital contracts do not represent a break with the general theory of contracts. On the contrary, they remain subject to the same requirements of validity, effectiveness and existence provided for in the legal system, especially with regard to the capacity of the parties, the lawfulness of the object and, above all, consent.

However, the incorporation of complex technologies, especially systems based on Artificial Intelligence, introduces new challenges to contractual dogmatics, requiring a critical rereading of classical institutes, notably with regard to the formation of will and liability for damages.

In this context, the analysis of digital contracts reveals a growing tension between the formality of consent and its effective substantiality, as well as imposes reflections on the limits of private autonomy in technologically opaque environments.

Digital Contracts and the Maintenance of the Classic Structure

Digital contracts, despite their technological clothing, remain anchored in the traditional foundations of Contract Law. Its formation requires the presence of essential elements, among which the valid consent of the parties, free of defects, stands out.

In this sense, the doctrine emphasizes that the agreement of wills continues to be the driving element of the legal relationship, and it is essential that there is coincidence between the volitional manifestations of the contracting parties regarding the existence, object and contractual clauses.

From this perspective, digital contracts can be understood as typical contracts signed in a virtual environment, with no change in their legal nature.

However, technological innovation allows the emergence of new contractual dynamics, in which, in certain cases, automated systems and algorithms start to play a relevant role in the formation and execution of the contract, and may even assume functions traditionally attributed to human will.

This reality imposes a broadening of the legal debate, especially with regard to the imputation of responsibility and the very understanding of consent.

The Erosion of Consent in the Digital Environment

The growing use of digital adhesion contracts, such as terms of use, privacy policies and general conditions of services, shows a practical weakening of consent.

Although formally existing, user consent is often limited to the automatic acceptance of extensive, complex and technically dense clauses, without an effective understanding of their content.

In this scenario, the so-called informed consent, understood as an expression of qualified private autonomy, becomes an ideal that is difficult to achieve. The complexity of technological systems, combined with the opacity of their internal mechanisms, makes it difficult for the user to be fully aware of the risks, criteria and consequences involved in contracting.

The situation worsens when considering systems based on Artificial Intelligence, whose decision-making logic is often presented as a true “black box”, inaccessible to the understanding of the average user.

Thus, consent ceases to be substantial and becomes merely formal, compromising the very validity of the legal transaction.

Defects of Consent: Substantial Error and Intent by Omission

The validity of the legal transaction requires that the will be manifested freely and consciously, without the incidence of defects. The Brazilian Civil Code provides, among the defects of the legal transaction, error and willful misconduct, capable of making the act voidable.

In the context of digital contracts mediated by Artificial Intelligence, the relevance of algorithmic opacity as a factor potentially generating consent defects is highlighted.

1. Erro Substancial

The lack of transparency regarding the operation of the systems may constitute a substantial error, under the terms of article 139, I, of the Civil Code, especially when it falls on the nature of the business or its main purpose.

The user, when contracting a digital service, presumes to be adhering to objective and understandable criteria. However, in practice, it is subject to automated decisions based on complex, potentially biased and unpredictable algorithms.

This discrepancy between the perception of the contractor and the reality of the contracted service compromises the valid formation of will.

2. Intent by Omission

In addition, the occurrence of intent by omission (article 147 of the Civil Code) can be considered when the supplier, aware of the risks inherent in the use of Artificial Intelligence, fails to inform such aspects adequately.

Intentional silence on relevant elements, which could influence the user’s decision, constitutes a violation of the duty of transparency and objective good faith, making consent legally vitiated.

The problem gains even more relevant contours in light of the General Data Protection Law (LGPD), which requires that consent for the processing of personal data be free, informed, and unequivocal, prohibiting generic or obscure practices.

Emblematic cases of massive and non-transparent data collection demonstrate the fragility of consent in the digital environment, showing that the user is often not even aware of the risks to which he is subjecting.

Defect of Consent and Civil Liability

The analysis of digital contracts reveals a close interdependence between the validity of the formation of the contract and the attribution of civil liability.

When the contract is entered into under a defect of consent, especially due to technological opacity, there is no need to speak of legitimate transfer of risks to the user.

Unlike parity contracts, in which the parties can deliberately allocate risks, digital adhesion contracts often impose such risks unilaterally and non-transparently.

In this case, the risk of the activity remains in the legal sphere of the supplier, who has control over the technology used.

Such a finding has direct implications in the analysis of the causal link, ruling out any allegations of risk assumption by the user and reinforcing the possibility of strict liability of the supplier for damages resulting from systemic failures or automated decisions.

Thus, the defect in the formation of the will not only compromises the validity of the contract, but also grounds the imputation of liability in terms of default and reparation of damages.

Conclusion

Digital contracts, although formally inserted in the classic structure of Contract Law, reveal profound transformations in their internal dynamics, especially in the face of the incorporation of complex technologies such as Artificial Intelligence.

The algorithmic opacity, the massification of adhesion contracts, and the informational asymmetry between supplier and user call into question the very notion of consent as a legitimate expression of private autonomy.

In this scenario, contractual dogmatics is challenged to reinterpret its fundamental institutes, in order to ensure not only the formal validity of contracts, but the effective protection of the will and dignity of the contracting party.

More than ever, it is essential to recognize that technological innovation cannot serve as an instrument to empty legal guarantees, and it is the duty of the Law to rebalance these relations, ensuring transparency, responsibility and justice in the new forms of contracting.

After all, if the contract continues to be the expression of the will, it is imperative that this will remains free, conscious and, above all, truly informed, under penalty of becoming a mere legal fiction in the face of the complexity of the digital world.

Bárbara Rita Lamarca Escapin – Lawyer, graduated in Law from Faculdades Integradas Rio Branco – Fundação de Rotarianos de São Paulo, registered with the Brazilian Bar Association, São Paulo Section (OAB/SP). Degree in Executive Education/Compliance from Fundação Getúlio Vargas. Postgraduate degree in Business Law from Fundação Getúlio Vargas. Attending the Advanced MBA in Business Management at FIA Business School. Author of articles. Lawyer and Chief Off Staff at TM Associados.

Gabriela Pelucio Winck – Lawyer, registered with the Brazilian Bar Association, São Paulo Section (OAB/SP). Master’s student in Comparative Civil Law at the Pontifical Catholic University of São Paulo, Post-Graduate in Contract Law, as well as in Administrative and Constitutional Law, both at Escola Paulista de Direito, Graduated in Law from the Pontifical Catholic University of São Paulo. Degree in Succession Planning from the Pontifical Catholic University of Paraná. Author of articles. Lawyer at TM Associados.

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