The convergence of bioelectronics and soft material engineering enables the next generation of ingestible devices that are capable of engaging with internal organs with high specificity. This work presents the development of SIRI-BE (Soft Intestinal Retentive Interface for BioElectronics), a minimally invasive flexible system for neural and hormonal modulation in the small intestine. The device integrates kirigami-patterned thin-film polyimide substrates with bioinspired microneedle arrays to achieve mechanical anchoring on mucosal tissues and maintain biocompatibility and the compliance of gastrointestinal biomechanics. Finite-element models combined with ex-vivo and in-vivo characterization demonstrate that kirigami-enabled deformation and controlled buckling enable stable retention without tissue perforation.