Smart Contracts, Contractual Principles and Contractual Justice: Self-Executability, Good Faith and Revisional Remedies in Brazilian Law

Abstract

This article examines the structural tension between the self-enforceability of smart contracts and the contractual principles enshrined in Brazilian civil law, as systematized by Orlando Gomes: party autonomy, consensualism, binding force, good faith, contractual economic equilibrium, and the social function of contract. It is argued that smart contracts, regardless of the platform on which they operate, constitute juridical acts (negócios jurídicos) under Brazilian law and, as such, are fully subject to the legal regime governing contracts. The article advances two converging theses. The first, pertaining to the law of obligations, demonstrates that algorithmic self-enforceability, while maximizing efficiency in securing the genetic synallagma, is structurally incompatible with revisionary remedies, notably the doctrine of unforeseen circumstances (Teoria da Imprevisão) and relief from excessive onerousness, unless opening mechanisms allowing for human intervention are programmed into the contract. The second thesis, of a principle-based nature, argues that algorithmic trust does not eliminate contractual good faith but rather reconfigures it: it renders good faith simultaneously more necessary, given the informational asymmetries created by technical opacity, and more difficult to operationalize, given the deterministic rigidity of code. This demands a displacement of its incidence toward the stages of contract design and subsequent judicial review. Good faith thus emerges as the normative instrument that enables the effective justice arising from the dynamic synallagma in smart contracts, the concept that reopens the possibility of correction that self-enforceability tends to foreclose. The institutional setting of the Drex project, whose blockchain platform was shut down by the Central Bank of Brazil in November 2025 due to technical infeasibility in meeting the non-waivable requirements of the national financial system, confirms, at the level of monetary policy, the article's central thesis: when algorithmic self-enforceability collides with non-waivable legal principles, it is the technology that must yield until a solution compatible with the legal principles of the system is found.