This action research examined the process of integrating students' out-of-school digital literacy into a second language composition class and the role of social mediation in developing learner agency. It involved EFL students with pre-basic and basic proficiency (pre-A1 to A1-A2 on the CEFR level) in a Saudi Arabian university. Using socially mediated view of literacy and learner agency as a theoretical framework, this study reveals the complex ways in which the students composed multimodal texts while relying on their agency to utilize the digital tools. Data sources include interviews with the students, teacher-researcher reflections, and the students' multimodal texts. The data reveal that through three distinct bridging practices, the students skillfully navigated through different reading sources and digital tools when they composed their multimodal texts ("technological bridging"), thus affording the opportunities for them to express themselves authentically ("identity bridging") and to engage with the text that they composed meaningfully ("semiotic bridging"). However, there was a trade-off in terms of the teacher's role in facilitating learner agency and linguistic accuracy. Focus on content lowered the bar on acceptable grammar mistakes. This insight corroborates existing literature on the need for a balanced pedagogical focus on content and accuracy in multimodal composition. This study has implications for teachers who wish to reimagine EFL composition by connecting it to students' literacy practices, particularly to those with pre-basic and basic proficiency.