Agent Browser CLI
vercel-labs/agent-browser
Browser automation CLI for AI agents. Use when the user needs to interact with websites, including navigating pages, filling forms, clicking buttons, taking…
Drives desktop Electron apps already installed on your machine, such as Slack, Discord or VS Code, by relaunching them with a debugging port and using the Libretto CLI.
Install External Electron App Automation
$ npx skills add cashew-labs/libretto --skill external-electron-apps -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install cashew-labs/libretto external-electron-apps --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/cashew-labs/libretto.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/external-electron-apps .claude/skills/external-electron-apps && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "external-electron-apps" agent skill from https://github.com/cashew-labs/libretto/tree/main/.agents/skills/external-electron-apps into .claude/skills/external-electron-apps/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "external-electron-apps", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/cashew-labs/libretto/tree/main/.agents/skills/external-electron-appsType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add cashew-labs/libretto --skill external-electron-apps -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install cashew-labs/libretto external-electron-apps --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/cashew-labs/libretto.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/external-electron-apps .agents/skills/external-electron-apps && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "external-electron-apps" agent skill from https://github.com/cashew-labs/libretto/tree/main/.agents/skills/external-electron-apps into .agents/skills/external-electron-apps/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "external-electron-apps", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add cashew-labs/libretto --skill external-electron-apps -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install cashew-labs/libretto external-electron-apps --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/cashew-labs/libretto.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/external-electron-apps .cursor/skills/external-electron-apps && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "external-electron-apps" agent skill from https://github.com/cashew-labs/libretto/tree/main/.agents/skills/external-electron-apps into .cursor/skills/external-electron-apps/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "external-electron-apps", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/cashew-labs/libretto.git --path .agents/skills/external-electron-apps--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add cashew-labs/libretto --skill external-electron-apps -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install cashew-labs/libretto external-electron-apps --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/cashew-labs/libretto.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/external-electron-apps .gemini/skills/external-electron-apps && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "external-electron-apps" agent skill from https://github.com/cashew-labs/libretto/tree/main/.agents/skills/external-electron-apps into .gemini/skills/external-electron-apps/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "external-electron-apps", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install cashew-labs/libretto external-electron-appsInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add cashew-labs/libretto --skill external-electron-apps -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/cashew-labs/libretto.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/external-electron-apps .github/skills/external-electron-apps && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "external-electron-apps" agent skill from https://github.com/cashew-labs/libretto/tree/main/.agents/skills/external-electron-apps into .github/skills/external-electron-apps/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "external-electron-apps", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add cashew-labs/libretto --skill external-electron-apps -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install cashew-labs/libretto external-electron-apps --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/cashew-labs/libretto.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/external-electron-apps .opencode/skills/external-electron-apps && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "external-electron-apps" agent skill from https://github.com/cashew-labs/libretto/tree/main/.agents/skills/external-electron-apps into .opencode/skills/external-electron-apps/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "external-electron-apps", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
external-electron-apps- GitHub stars
- 904
- Token cost
- ~967 tokens
- SKILL.md length
- 272 words
- Files
- 1
- Skills in repo
- 21
- Repo updated
- First seen
- Licence
- MIT
At a glance
Drives desktop Electron apps already installed on your machine, such as Slack, Discord or VS Code, by relaunching them with a debugging port and using the Libretto CLI.
- Works in 7 steps: Quit the app if it is already running. → Relaunch the app with… → Connect with npx libretto connect… → …
- Automating a local desktop app such as Slack or VS Code
- SKILL.md covers Core workflow, Launch examples, Session pattern and Interaction examples, plus 3 more sections
- Calls npx
What it does
This skill is for controlling third-party Electron desktop apps through the Chrome DevTools Protocol, and it tells the agent not to use it for the repository's own Electron app unless asked. The workflow is: quit the app, relaunch it with the remote debugging port flag, connect with npx libretto connect under a named session, list targets with pages, run code with exec, capture evidence with snapshot, and later run a saved workflow file with libretto run and a CDP address.
Launch commands are given for macOS, Linux and Windows, using Slack, VS Code and Discord on separate ports. It recommends one session per app, notes that Electron apps often have several windows and shows how to pick one with the page option, and suggests taking a snapshot or reading the page content when selectors are unstable. The excerpt is cut off before the scripted workflows section.
When your agent uses it
- Automating a local desktop app such as Slack or VS Code
- Connecting to an Electron app through its remote debugging port
- Inspecting a desktop app's page content when selectors are unreliable
- Turning a manual desktop app task into a reusable Libretto workflow
Example prompts
- “Relaunch my Slack desktop app with a debugging port and search for incident-123.”
- “Connect to the VS Code window with Libretto and list the pages it exposes.”
- “Take a snapshot of the Discord desktop app and tell me what is on screen.”
- “Save the Notion desktop steps we just ran as a workflow file I can rerun.”
Requirements
- Node.js with `npx` to run the Libretto CLI
- The target Electron app installed locally
Workflow steps
7 steps, taken from the first numbered list in SKILL.md.
- Quit the app if it is already running.
- Relaunch the app with --remote-debugging-port=.
- Connect with npx libretto connect http://127.0.0.1: --session .
- Verify targets with npx libretto pages --session .
- Run interactions with npx libretto exec "" --session .
- Capture evidence with npx libretto snapshot --session .
- When a reusable workflow file is ready, execute it with npx libretto run ./workflow.ts --cdp http://127.0.0.1: (optional --page page-N).
What it can do on your machine
Read from SKILL.md and the folder at commit 41ab782. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
npx
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use npx, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
External Electron App Automation loads about 967 tokens when it runs. Until then it costs about 102 tokens; SKILL.md has 272 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from cashew-labs/libretto at commit 41ab782, republished under its MIT licence (© cashew-labs). 272 words, ~967 tokens.
Download SKILL.mdSave it as
.claude/skills/external-electron-apps/SKILL.md (or your agent's skills folder).- name
- external-electron-apps
- description
- Automate user-installed Electron desktop apps (Slack, Discord, VS Code, Notion, Figma, Spotify, etc.) via CDP using this repo's Libretto CLI. Use when the task is to control a local desktop app on the user's machine, not this repo's own Electron app. Triggers: "desktop Slack app", "connect to Electron app", "remote-debugging-port", "CDP desktop app", "automate VS Code desktop app".
External Electron App Automation
Use this skill for external Electron desktop apps running on the user's machine. Do not default to this for this repository's own Electron app unless the user explicitly asks.
Core workflow
- Quit the app if it is already running.
- Relaunch the app with
--remote-debugging-port=<port>. - Connect with
npx libretto connect http://127.0.0.1:<port> --session <session>. - Verify targets with
npx libretto pages --session <session>. - Run interactions with
npx libretto exec "<code>" --session <session>. - Capture evidence with
npx libretto snapshot --session <session>. - When a reusable workflow file is ready, execute it with
npx libretto run ./workflow.ts --cdp http://127.0.0.1:<port>(optional--page page-N).
Launch examples
macOS
open -a "Slack" --args --remote-debugging-port=9222
open -a "Visual Studio Code" --args --remote-debugging-port=9223
open -a "Discord" --args --remote-debugging-port=9224Linux
slack --remote-debugging-port=9222
code --remote-debugging-port=9223
discord --remote-debugging-port=9224Windows
"C:\Users\%USERNAME%\AppData\Local\slack\slack.exe" --remote-debugging-port=9222
"C:\Users\%USERNAME%\AppData\Local\Programs\Microsoft VS Code\Code.exe" --remote-debugging-port=9223Session pattern
Use one session per app:
npx libretto connect http://127.0.0.1:9222 --session slack-desktop
npx libretto pages --session slack-desktop
npx libretto exec "return await page.title()" --session slack-desktop
npx libretto snapshot --session slack-desktopInteraction examples
npx libretto exec "await page.locator('button:has-text(\"Search\")').click()" --session slack-desktop
npx libretto exec "await page.keyboard.type('incident-123')" --session slack-desktop
npx libretto exec "await page.keyboard.press('Enter')" --session slack-desktopWhen selectors are unstable, inspect first:
npx libretto snapshot --session slack-desktop
npx libretto exec "return await page.content()" --session slack-desktopMultiple pages
Electron apps often have multiple windows/pages. Use pages to list them and --page to target a specific one:
npx libretto pages --session slack-desktop
npx libretto exec --session slack-desktop --page <page-id> "return await page.url()"
npx libretto snapshot --session slack-desktop --page <page-id>Scripted workflows
After interactive discovery, run a default-exported workflow() against the same CDP endpoint. Libretto attaches to the selected page without navigating to workflow startUrl, so leave the app on the target screen first (or navigate in the handler). Closing the Libretto session does not quit the Electron app.
npx libretto run ./slack-workflow.ts --cdp http://127.0.0.1:9222
npx libretto run ./slack-workflow.ts --cdp http://127.0.0.1:9222 --page page-1Troubleshooting
- If connection fails, make sure the app was launched with
--remote-debugging-portand relaunch it. - Prefer
127.0.0.1overlocalhostin CDP URLs. - If no pages are listed right after launch, wait 2-5 seconds and retry
pages. - If a session is stale, run
connectagain with the same--session.
Use npx libretto close --session <session> to clear the session. This does not terminate the external app — it only removes the session state so Libretto stops tracking it.
© cashew-labs, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in .agents/skills/external-electron-apps of cashew-labs/libretto.
Open the folder on GitHubat commit 41ab782
Compare with similar skills
External Electron App Automation next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| External Electron App Automation this skillcashew-labs/libretto | 904 | — | ~967 | Automated safety check: Pass | MIT | |
| Agent Browser CLIvercel-labs/agent-browser | 44k | 24 repos | ~864 | Automated safety check: Pass | Apache-2.0 | |
| Electron App Automationvercel-labs/agent-browser | 44k | 5 repos | ~1.7k | Automated safety check: Pass | Apache-2.0 | |
| ComposioComposioHQ/composio | 30k | 1 repos | ~1.7k | Automated safety check: Pass | MIT | |
| Connect Apps with ComposioComposioHQ/awesome-claude-skills | 77k | 3 repos | ~557 | Automated safety check: Pass | None | |
| Openloomi Connectorsmelandlabs/openloomi | 1k | — | ~3.3k | Automated safety check: Pass | Apache-2.0 |
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Categories
Questions about External Electron App Automation
What does External Electron App Automation do?
Drives desktop Electron apps already installed on your machine, such as Slack, Discord or VS Code, by relaunching them with a debugging port and using the Libretto CLI. This skill is for controlling third-party Electron desktop apps through the Chrome DevTools Protocol, and it tells the agent not to use it for the repository's own Electron app unless asked. The workflow is: quit the app, relaunch it with the remote debugging port flag, connect with npx libretto connect under a named session, list targets with pages, run code with exec, capture evidence with snapshot, and later run a saved workflow file with libretto run and a CDP address.
When should I use External Electron App Automation?
External Electron App Automation fits situations like: automating a local desktop app such as Slack or VS Code; connecting to an Electron app through its remote debugging port; inspecting a desktop app's page content when selectors are unreliable; turning a manual desktop app task into a reusable Libretto workflow.
How do I install External Electron App Automation in Claude Code?
Run `npx skills add cashew-labs/libretto --skill external-electron-apps -a claude-code`. Or copy the skill folder (.agents/skills/external-electron-apps in cashew-labs/libretto) into .claude/skills/external-electron-apps in your project. Claude Code loads it when a task matches its description.
How do I install External Electron App Automation in Codex?
Run `npx skills add cashew-labs/libretto --skill external-electron-apps -a codex`. Or copy the skill folder (.agents/skills/external-electron-apps in cashew-labs/libretto) into .agents/skills/external-electron-apps in your project. Codex loads it when a task matches its description.
Can I use External Electron App Automation in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add cashew-labs/libretto --skill external-electron-apps -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/external-electron-apps, .gemini/skills/external-electron-apps, .github/skills/external-electron-apps and .opencode/skills/external-electron-apps in your project.
What does External Electron App Automation need to run?
Going by SKILL.md and its folder, External Electron App Automation needs the command-line tools its instructions call (npx). Our summary lists: Node.js with `npx` to run the Libretto CLI; The target Electron app installed locally.
Does External Electron App Automation access the network?
SKILL.md contains no URLs. Its commands use npx, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is External Electron App Automation safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does External Electron App Automation use?
External Electron App Automation is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does External Electron App Automation use?
About 967 tokens (SKILL.md is roughly 3.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to External Electron App Automation?
Skills that share tags, products or a category with External Electron App Automation: Agent Browser CLI (vercel-labs/agent-browser, 44k stars), Electron App Automation (vercel-labs/agent-browser, 44k stars), Composio (ComposioHQ/composio, 30k stars) and Connect Apps with Composio (ComposioHQ/awesome-claude-skills, 77k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains External Electron App Automation?
cashew-labs (a GitHub organization) maintains it in cashew-labs/libretto, which has 904 GitHub stars. The repository holds 21 skills in this directory. The repository was last updated on August 21, 2026.
Source: cashew-labs/libretto on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.