dsh-cdp-browser

In the DeepSeek Harness sandbox, the traditional approach of spawning a browser process and piping its stdio keeps hitting EPERM/EINVAL because the sandbox forbids pipe operations. dsh-cdp-browser takes a different route: it connects to a Chrome or Edge instance the user has already launched via the Chrome DevTools Protocol. Browser control becomes plain network I/O, sidestepping all child-process and pipe restrictions, and the model no longer needs per-call human approval for visual checks.

The plugin relies solely on Node 22 built-ins—global fetch, WebSocket, and zlib PNG decoding—with zero npm dependencies and no child_process. It ships five tools: list open tabs (cdp_status), open or reuse a page (cdp_open), evaluate page-level JavaScript (cdp_eval), navigate and capture a PNG screenshot (cdp_shot), and the centerpiece, cdp_assert—scripted interaction layered with deterministic pixel, CSS, DOM, and JS assertions that produce a pass/fail report. Pixel checks include gradient-aware sampling and tolerance-based colour matching to avoid false positives in transition zones.

It is aimed at developers who need browser end-to-end verification, visual regression testing, or simply want the model to inspect page rendering inside a confined Harness environment. After the one-time manual step of launching a CDP-enabled browser, every subsequent visual check runs silently with no human involvement.