---
name: desktop-electron-dev-attach
description: Interactively attach to an already-running Electron app through stable DESKTOP_CDP_PORT for local development or requested desktop happy-path verification with Playwright or OpenCode MCP.
---

# Desktop Electron Dev Attach

Use this guidance only for interactive attachment to an already-running desktop app. Load
`test-layer-fit` instead when designing a scripted Electron suite, its application lifecycle, or its
cleanup ownership.

## Port Contract

- `DESKTOP_DEV_PORT` is the renderer dev server port for `apps/desktop`.
- `DESKTOP_CDP_PORT` is the Electron CDP / remote-debugging attach port for Playwright Electron and
  OpenCode MCP.
- Keep `DESKTOP_CDP_PORT` unique across simultaneously running desktop apps to avoid CDP collisions.
- Concrete port values live in the target repo's `.env`, `.env.example`, nearest app `AGENTS.md`, or
  repo guidance. Read them from the repo; do not hardcode shared values in this skill.
- If a repo has a configured OpenCode Playwright Electron MCP endpoint, it must point at the same
  `http://localhost:<DESKTOP_CDP_PORT>` used by that repo's desktop app.

## Development Attach

- Start or use the already-running desktop app for the target repo before attaching.
- Attach Playwright Electron through the app-window CDP target. Select the app window or tab, not
  DevTools.
- Configured CDP endpoints can exist even when the matching Electron app is not running; treat a
  missing target as an app startup or port mismatch problem, not as proof.
- Do not infer desktop proof from web or mobile evidence.

## E2E Separation

- Stable interactive development attach uses `DESKTOP_CDP_PORT`.
- Scripted desktop E2E launches a Playwright-owned Electron application with isolated user data. It
  does not attach to the stable development CDP target or create a parallel scripted-E2E CDP default.
- Do not repoint automated E2E scripts to the stable development CDP port.

## Repo-Owned Details

Keep these values in the target repo or app guidance, not in this shared skill:

- concrete `DESKTOP_DEV_PORT` and `DESKTOP_CDP_PORT` values
- app slug and token storage key prefixes
- desktop routes and expected final screens
- API origins, auth endpoints, headers, cookies, and storage keys
- Electron preload, IPC, and storage adapter details
- OpenCode MCP endpoint names and workspace-specific configuration paths