This study aims to develop a Gemini AI-based learning medium with structured feedback to improve the writing achievement of speech texts among eighth-grade junior high school students. The study was conducted in the even semester of the 2025/2026 academic year at SMP Budi Murni 2 Medan, using a Research and Development approach with the ADDIE model (Analysis, Design, Development, Implementation, Evaluation). The research subjects consisted of two content experts, two media experts, one eighth-grade Indonesian language teacher, and 30 eighth-grade students as questionnaire respondents and writers of the speech texts analyzed through the medium. Data were collected through expert validation sheets, teacher and student response questionnaires, observation and interview guidelines, and writing tests, then analyzed descriptively using qualitative and quantitative techniques, with Likert-scale scores converted into percentages. The results show that the resulting product is a web-based learning medium accessible at https://mrdatoai.my.id/, consisting of four main menus (Home, Materials, Sample Speeches, Practice) with a three-stage writing flow (Initial Text, Revision, Final Text), each accompanied by automatic feedback based on a seven-aspect assessment rubric. The medium is categorized as Highly Feasible (average 89.55%) and very high (average 89.9%), supported by writing achievement that increased gradually from 74.83 to 88.47 and classical mastery from 40.00% to 83.33%. The medium is declared valid and practical for use as a supporting alternative for teaching speech-text writing in eighth grade.