arXiv:2610.27170v1 Announce Type: new Abstract: Agentic systems increasingly carry out complex work, where a single turn routinely runs for minutes. This produces a micro-wait that is too long to watch and too short to leave. In a formative study with 12 daily agent users, we found that staying felt like wasted time, while switching away fragmented attention and forfeited the context needed to re-engage. We introduce Sidecar, a parallel assistant situated in the same interface as the agent, which reads the run and surfaces implicit decisions the agent made, along with task directions worth exploring. In a within-subjects study (N=16), Sidecar helped participants stay focused on their main task, freely workshop unfinished ideas without fear of unwanted action, and recognize under-specification in their own prompts. Together, these findings contribute to designs that help users stay context-aware and engaged during agent micro-waits.