browser

name	browser
description	Open, navigate, screenshot, read, click, and type in web pages from an agent. Use when the user asks to open a URL, preview or verify a running web app, check a page's console, fill a form, click through a web flow, or automate anything in a browser, including "open localhost:3000", "screenshot the page", "what does the console say", "click the submit button". Drives the in-app browser pane of a Superset workspace by default and Browser Use for browsers the panes cannot reach.
argument-hint	URL or what to do in the browser
allowed-tools	Bash(superset:*) Bash(curl:*)

Superset Browser Control

Drive web pages through the browser panes inside a Superset workspace with the superset browser commands. Every operation runs in the pane the user can see, against the pane's real, logged-in session. A raw Chrome DevTools Protocol (CDP) endpoint covers anything the high-level verbs don't.

Choose a surface

• If a plain HTTP request or an API can answer (a public page, docs, a JSON endpoint), use curl or your fetch tool and skip the browser.
• Default to the in-app pane whenever the page is, or can be, open in a workspace pane: previewing a dev server, verifying UI the user is watching, clicking through a flow in the app.
• Use Browser Use only when the panes cannot reach the target: a Chrome window outside Superset, a host with no desktop app attached (pane commands error clearly there), or work that needs an isolated or cloud browser. Read references/browser-use.md before using it; it covers install consent, attaching, and cleanup.

Browser Use can also drive a pane, and for three kinds of pane task it's the nicer tool: an open-ended goal to run end to end ("get through this signup"), a long multi-step flow on a shifting UI, or a recorded walkthrough. If one of those fits and Browser Use isn't installed, offer it once ("I can hand this to Browser Use, which drives multi-step flows more cleanly, but it's a one-minute install. Want that, or should I drive the pane directly?"), then respect the answer for the rest of the session, and hand a pane to Browser Use only after the user has said yes (the pane is their signed-in session and its CDP URL carries a token). Don't offer it for a screenshot, one eval, or a plain read; the pane verbs already cover those.

Establish the control surface

1. Run superset browser --help and require list, open, navigate, screenshot, eval, console, and cdp. If absent, run superset update and recheck. The app-bundled CLI (~/.superset/bin/superset) updates only with the desktop app, so if it lacks browser, updating the app is the fix; check type -a superset for another install before giving up.
2. Resolve the workspace. Inside a workspace, use $SUPERSET_WORKSPACE_ID; otherwise superset workspaces list --local --json and pick the target. Pass --host <id> for a remote host.
3. Panes live in the desktop app. A host with no desktop attached (a standalone superset start) has no panes and every command errors clearly; surface that rather than retrying.

Find or open a pane

Every pane has a stable paneId, scoped to its workspace: pass the same --workspace you opened it under or the operation is rejected.

superset browser list --workspace <id> --json
superset browser open --workspace <id> --url https://example.com --json
superset browser open --workspace <id> --url http://localhost:3000 --target new-tab --json

--target new-tab opens a fresh tab and focuses it; the default current-tab reuses the active browser pane. Opening needs the workspace visible in the desktop app (the renderer creates the pane), so if it times out, ask the user to open the workspace.

Drive with the high-level verbs

# Point an existing pane at a new URL
superset browser navigate --workspace <id> --pane <paneId> --url https://…

# Capture a PNG (base64 by default; --out writes a file)
superset browser screenshot --workspace <id> --pane <paneId> --out shot.png

# Read the pane's captured console output
superset browser console --workspace <id> --pane <paneId> --max-lines 100

# Evaluate JavaScript in the page and return the result
superset browser eval --workspace <id> --pane <paneId> \
  --code "document.querySelector('h1')?.textContent"

Screenshot to see state, eval to read structured data (.textContent, .value = …, element.click(), location.href), console to check for page errors. Prefer these over raw CDP unless you need real input events. An eval expression that throws comes back as a command error, not a value. open and navigate accept only http(s) and about: URLs; bare input like localhost:3000 is upgraded, while file://, chrome://, and data: are rejected with a clear error.

Import logins from another browser

import-login copies a system browser's cookies into the pane so it's signed in to the sites the user already uses. It imports every cookie that profile has on disk, not just the one site, and panes share a profile, so say that when offering and run it only with the user's go-ahead. Offering it is how most users discover it: when a pane hits a login wall for a site the user uses in their own browser, suggest importing that login instead of stopping. The user always picks the source browser; people run several Chromium browsers (Chrome, Edge, Brave, Arc, Dia, Comet) and only they know which holds the session. macOS only; it reads the browser's Keychain key (first run prompts them to allow it) and never modifies the source browser.

1. List the installed browsers and let the user choose: superset browser import-login --workspace <id> --pane <paneId>
2. Import from their choice, then reload the pane: superset browser import-login --workspace <id> --pane <paneId> --from Comet followed by superset browser navigate …. --profile <name> disambiguates a browser with several profiles; an ambiguous --from errors and lists them.

Only cookies written to disk can import. Many sites keep auth in session cookies that live in browser memory, so have the user quit the source browser first to flush its logins. imported: 0, keyUnavailable: true means the Keychain prompt was denied; ask them to allow it and retry.

Full interaction over raw CDP

For clicking, typing, scrolling, waiting on selectors, or any Playwright-class flow, get the pane's CDP WebSocket endpoint:

superset browser cdp --workspace <id> --pane <paneId> --json

The printed url speaks CDP directly (Page, Runtime, DOM, Input, Network, …). It embeds an auth token, so treat it as a secret and keep it out of shared logs. Minimal pattern (Node 22+ / Bun):

const ws = new WebSocket(cdpUrl);
let id = 0;
const send = (method, params) =>
  new Promise((resolve) => {
    const myId = ++id;
    const h = (e) => {
      const m = JSON.parse(e.data);
      if (m.id !== myId) return;
      ws.removeEventListener("message", h);
      resolve(m.result);
    };
    ws.addEventListener("message", h);
    ws.send(JSON.stringify({ id: myId, method, params }));
  });

await new Promise((r) => ws.addEventListener("open", r, { once: true }));
await send("Page.enable");
await send("Runtime.enable");
await send("DOM.enable");

// Focus a text field by resolving its center, then dispatching a real click.
 sel = ;
 { result } =  (, {
  : ,
  : ,
});
 (!result.)   ();
 { x, y } = result.;
 (, { : , x, y, : , :  });
 (, { : , x, y, : , :  });


 focused =  (, {
  : ,
  : ,
});
 (focused..)  (, { :  });

Gotchas that keep CDP flows reliable:

• One CDP session per pane. A second concurrent attach is rejected with close code 1013 until the first disconnects; close the socket when done, then retry.
• After a click that should focus a field, verify document.activeElement before Input.insertText, and poll a selector or state check after each action rather than sleeping a fixed time; the guest repaints slowly when the window is backgrounded.
• To submit with Enter, the keyDown must carry the character: {type: "keyDown", key: "Enter", code: "Enter", text: "\r", unmodifiedText: "\r", windowsVirtualKeyCode: 13} then the matching keyUp. Without text: "\r" no char is generated and forms silently don't submit.
• Page.navigate obeys the same scheme allowlist as the CLI.

Verify

Confirm outcomes from the page itself, not from the fact a command returned: read back location.href, the DOM via eval, or a screenshot after each meaningful step, and check the console for page errors before declaring success.

Safety

• In-app panes share one browser profile, so eval and CDP reach whatever the user is logged into in any pane (GitHub, dashboards, …). Never read cookies, tokens, or credentials, exfiltrate session data, or act on authenticated sites beyond the task.
• Confirm with the user before a step that submits a form, makes a purchase, or takes another consequential action.
• Login walls stay with the user: never enter passwords or MFA yourself. At a login wall you may offer import-login (above) rather than only stopping.
• Never install Browser Use, enable Chrome remote debugging, attach to the user's signed-in profile, or start a billed cloud browser without explicit consent. If consent is refused, report what you couldn't do rather than working around it.
• Pane operations are scoped to the pane's workspace; don't reach panes in another workspace.
• Leave state clean. Navigating away from what the user was viewing is itself a change, so prefer --target new-tab for a scratch surface, and don't close their tabs or clear history unless asked.