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paseo/public-docs/browser-tools.md
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Browser tools The browser_* MCP tools agents use to drive Paseo browser tabs. Tools reference 36 Browser

Browser tools

The browser_* tools are injected into agents alongside the other Paseo MCP tools when browser automation is enabled.

Shared concepts:

  • browserId identifies a tab. It comes from browser_new_tab or browser_list_tabs and is required by every tab-scoped tool.
  • ref identifies an element, e.g. @e3. Refs come from the latest browser_snapshot of the same tab and expire when the page changes — stale refs return an error instead of acting on the wrong element.
  • Every result reports dialogs the page opened during the command (alerts accepted; confirm/prompt/beforeunload dismissed).

Arguments marked ? are optional.

Tabs

Tool Arguments Purpose
browser_list_tabs List open tabs in the agent's workspace across connected hosts.
browser_new_tab url? Open a tab in the background and return its browserId.
browser_close_tab browserId Close a tab and clean up its webview.
browser_resize browserId, width, height Resize the tab's viewport — check a layout at phone or tablet dimensions.

Reading the page

Tool Arguments Purpose
browser_snapshot browserId Return the page as an accessibility tree with element refs.
browser_screenshot browserId, fullPage? Capture a PNG of the viewport, or the full page with fullPage.
browser_logs browserId, maxEntries? Read recent console messages and network timing entries.
browser_wait browserId, text? | url?, timeoutMs? Wait until the page contains text or reaches a URL fragment (exactly one of the two).

Interacting

Tool Arguments Purpose
browser_click browserId, ref, button?, doubleClick?, modifiers? Click an element — left/right/middle, double-click, keyboard modifiers.
browser_fill browserId, ref, value Set the value of an input-like element.
browser_type browserId, text, ref? Type text into an element, or into the focused element when ref is omitted.
browser_keypress browserId, key, ref? Press a key (Enter, Escape, Tab, Space, …) on an element or the focused one.
browser_hover browserId, ref Hover an element — triggers real CSS :hover.
browser_select browserId, ref, value Choose an option in a <select>.
browser_drag browserId, sourceRef, targetRef Drag one element onto another.
browser_upload browserId, ref, filePaths Set files on a file input. Paths must be inside the agent's workspace.
browser_scroll browserId, deltaX, deltaY, ref? Scroll the page, or center the wheel input over an element with ref.

Navigation

Tool Arguments Purpose
browser_navigate browserId, url Go to an http(s) URL.
browser_back browserId Go back — errors when there is no history to go to.
browser_forward browserId Go forward — errors when there is no forward entry.
browser_reload browserId Reload the page.

Scripting

Tool Arguments Purpose
browser_evaluate browserId, function, ref? Run a JavaScript function in the page. With ref, the resolved element is passed as the first argument. Results return as bounded JSON.

Errors

Tools return structured errors rather than failing silently. The ones agents see most:

Code Meaning
browser_disabled Browser tools are turned off on this host.
browser_no_host No browser host (desktop app) is connected. Retryable.
browser_stale_ref The ref no longer matches the page — take a new snapshot.
browser_timeout The element never became actionable, or the wait condition never held.
browser_denied The action isn't allowed — e.g. a non-http(s) URL, or no history to navigate.