Emulation

14 tools in this group.

`browser_get_viewport`

Get the current viewport dimensions

Parameter	Type	Required	Default	Description
`session`	`string`	no		Optional: named session to run this call in (default: current session).

`browser_set_viewport`

Set the browser viewport size. Use browser_reset_viewport to clear the override.

Parameter	Type	Required	Description
`devicePixelRatio`	`number`	no	Device pixel ratio (optional; must be > 0 and at most 10, e.g., 2 for Retina)
`height`	`integer`	yes	Viewport height in pixels (positive integer, maximum 16384)
`session`	`string`	no	Optional: named session to run this call in (default: current session).
`width`	`integer`	yes	Viewport width in pixels (positive integer, maximum 16384)

Reset the viewport size and device pixel ratio overrides for the current page/context, returning control of viewport sizing to the browser (WebDriver BiDi browsingContext.setViewport with viewport: null and devicePixelRatio: null).

Parameter	Type	Required	Default	Description
`session`	`string`	no		Optional: named session to run this call in (default: current session).

`browser_emulate_environment`

Emulate the browsing environment for this session: locale, timezone, user agent, offline network, disabled scripting. Overrides are scoped to the session's user context (new tabs inherit them; other sessions are unaffected) and persist until cleared. At least one setting is required. Note: page_clock_set_timezone sets a per-tab timezone that wins over this session-wide one in that tab.

Parameter	Type	Required	Description
`locale`	`string`	no	BCP 47 language tag (e.g. 'fr-CA'). Empty string clears the override.
`network`	`string`	no	Network conditions: "offline" emulates being offline, "default" restores real connectivity (one of: `offline`, `default`)
`scripting`	`string`	no	Scripting: "disabled" emulates JavaScript disabled for page content, "default" restores it (one of: `disabled`, `default`)
`session`	`string`	no	Optional: named session to run this call in (default: current session).
`timezone`	`string`	no	IANA timezone ID (e.g. 'Asia/Tokyo') or offset string (e.g. '+05:30'). Empty string clears the override.
`userAgent`	`string`	no	User-Agent string. Empty string clears the override.

`browser_emulate_media`

Override CSS media features (color scheme, reduced motion, etc.)

Parameter	Type	Required	Description
`colorScheme`	`string`	no	Color scheme: "light", "dark", or "no-preference" (one of: `light`, `dark`, `no-preference`)
`contrast`	`string`	no	Contrast preference: "more", "less", or "no-preference" (one of: `more`, `less`, `no-preference`)
`forcedColors`	`string`	no	Forced colors: "active" or "none" (one of: `active`, `none`)
`media`	`string`	no	Media type: "screen" or "print" (one of: `screen`, `print`)
`reducedMotion`	`string`	no	Reduced motion: "reduce" or "no-preference" (one of: `reduce`, `no-preference`)
`session`	`string`	no	Optional: named session to run this call in (default: current session).

`browser_set_geolocation`

Override the browser geolocation

Parameter	Type	Required	Default	Description
`accuracy`	`number`	no	`1`	Accuracy in meters (default: 1)
`latitude`	`number`	yes		Latitude (-90 to 90)
`longitude`	`number`	yes		Longitude (-180 to 180)
`session`	`string`	no		Optional: named session to run this call in (default: current session).

`page_clock_install`

Install a fake clock on the page, overriding Date, setTimeout, setInterval, requestAnimationFrame, and performance.now

Parameter	Type	Required	Description
`session`	`string`	no	Optional: named session to run this call in (default: current session).
`time`	`number`	no	Initial time as epoch milliseconds (optional)
`timezone`	`string`	no	IANA timezone ID to override (e.g. 'America/New_York', 'Europe/London')

`page_clock_fast_forward`

Jump the fake clock forward by N milliseconds, firing each due timer at most once

Parameter	Type	Required	Default	Description
`session`	`string`	no		Optional: named session to run this call in (default: current session).
`ticks`	`number`	yes		Number of milliseconds to fast-forward

`page_clock_run_for`

Advance the fake clock by N milliseconds, firing all time-related callbacks systematically

Parameter	Type	Required	Default	Description
`session`	`string`	no		Optional: named session to run this call in (default: current session).
`ticks`	`number`	yes		Number of milliseconds to advance

`page_clock_pause_at`

Jump the fake clock to a specific time and pause — no timers fire until resumed or advanced

Parameter	Type	Required	Default	Description
`session`	`string`	no		Optional: named session to run this call in (default: current session).
`time`	`number`	yes		Time as epoch milliseconds to pause at

`page_clock_resume`

Resume real-time progression from the current fake clock time

Parameter	Type	Required	Default	Description
`session`	`string`	no		Optional: named session to run this call in (default: current session).

`page_clock_set_fixed_time`

Freeze Date.now() at a specific value permanently. Timers still run.

Parameter	Type	Required	Default	Description
`session`	`string`	no		Optional: named session to run this call in (default: current session).
`time`	`number`	yes		Time as epoch milliseconds to freeze at

`page_clock_set_system_time`

Set Date.now() to a specific value without triggering any timers

Parameter	Type	Required	Default	Description
`session`	`string`	no		Optional: named session to run this call in (default: current session).
`time`	`number`	yes		Time as epoch milliseconds to set

`page_clock_set_timezone`

Override the browser timezone. Pass an IANA timezone ID (e.g. 'America/New_York'), or empty string to reset to system default

Parameter	Type	Required	Default	Description
`session`	`string`	no		Optional: named session to run this call in (default: current session).
`timezone`	`string`	yes		IANA timezone ID (e.g. 'America/New_York', 'Europe/London', 'Asia/Tokyo'). Empty string resets to system default.