This paper demonstrates how agency emerges as the teaching team members of three social science and humanities massive open online courses (MOOCs) reflexively discuss the affordances and limitations offered by edX. Special attention goes to the entanglement of forums within their courses. We examine the edX platform as a discursive-material knot, a dispositif that can be partially configured by teaching team members. The interviewees interpretively articulate institutional pressures, the technological characteristics of edX, perceived learner behaviours, and pedagogic theories and preferences constitutive of their MOOCs. We identify six forms of agency: catalyst, surveillance-based, expertise-oriented, socializing, guiding, and humanizing. We demonstrate that agency emerges due to the complex and interpretive articulations of material and discussive elements.