This article substantiates the institutional design of the Institute of State Innovation Support (IDIS) as a concrete embodiment of the entrepreneurial state concept (Mazzucato) adapted for the post-conflict governance context of Ukraine. Drawing on New Public Governance theory (Osborne), transaction cost economics (Coase, Williamson) and governance network theory (Rhodes), the article proposes a governance architecture in which IDIS operates as a hybrid public agency: combining a public strategic mandate with market-discipline mechanisms. The governance architecture is structured across five layers: strategic (parliamentary mandate and sunset review), oversight (independent supervisory board), operational (standardised package development), digital verification (ProZorro-principle platform + e-hryvnia DLT registry), and market discipline (differentiated guarantee deposit). A comparative analysis with Innovate UK, EIC Accelerator, DARPA/ARPA-E and Israel's Yozma programme confirms that IDIS is unique in simultaneously combining self-sustainability (revolving fund), market discipline and sector neutrality. A typological comparison across seven criteria demonstrates IDIS's structural advantages over classic subsidies, PPPs and grants. Scientific novelty: the article introduces the concept of «accountability by design» as the defining architectural principle of a new class of post-conflict public innovation institutions.