The typical AI coding agent is invisible. It runs in a terminal, churns through files, and unless you're actively watching, you have no idea what it's doing. Glimpse is a small open-source library that tries to fix that — without the usual cost.
Built by GitHub user 'hazat', Glimpse opens a native WKWebView window in under 50ms and communicates with the host process via a bidirectional JSON Lines protocol over stdin/stdout. It ships as the npm package 'glimpseui' and compiles a Swift binary on install. No Electron, no browser runtime, no sprawling dependency tree.
Window behaviour is controlled through composable flags — 'frameless', 'floating', 'transparent', 'clickThrough' — that can be stacked to produce anything from a simple dialog to a ghost overlay that hovers above the desktop without intercepting mouse events. The most distinctive mode is 'followCursor', which attaches a window to the user's pointer in real time across multiple displays. Six named snap-point anchors let you position it relative to the cursor; spring physics can be enabled for iOS-style elastic tracking.
The library ships with a first-party integration for 'pi', the coding agent by mariozechner. Running 'pi install npm:glimpseui' installs a Glimpse skill and a floating status pill that trails the cursor and displays live agent activity — toggled with '/companion'. It's a narrow feature, but it points at something real: agents running in the background need some way to signal their presence without demanding your full attention.
For now, Glimpse is macOS-only, which limits its reach. But the approach — a tiny Swift binary, sub-50ms cold starts, physics-aware cursor tracking — sketches out what ambient agent UI might look like as these tools migrate from terminals into the visual layer of the operating system.