<![CDATA[Vocabulary learning is a gradual process that requires students' autonomy to support their vocabulary development. Metacognitive strategies encourage students to plan, monitor, and evaluate their learning progress. Furthermore, in the digital era, AI-assisted tools can support students to maintain self-regulated learning. Using a case study design, this inquiry uses interviews and questionnaires to collect data from a group of senior high school students. Twenty students participated in the investigation during a four-week implementation of a metacognitive strategy in a narrow reading program. The questionnaire was distributed before and after the program. To capture students' experiences during the program, students were instructed to write a reading journal. All data sources were analyzed descriptively. The results show that most senior high school students are familiar with using ChatGPT and Google Gemini. Indeed, in the context of vocabulary lookup, they have utilized the combination of Google Lens and Google Translate. The way students use AI-assisted tools has varied according to their level of proficiency. Students with limited vocabulary coverage used AI tools to improve their comprehension. Conversely, students with a sufficient vocabulary level used AI as a partner to enrich their knowledge and learn vocabulary productively. These findings yield two instructional implications: first, teachers need to guide students in using AI responsibly while integrating it into the learning process. Second, having access to AI tools is not enough; students must be prepared to become autonomous learners so they become lifelong learners.]]>
