Every browser workflow starts with browser_start and ends with browser_end.

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Session

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browser_start

Start or reuse a browser session. Must be called before any other browser tools. Reuses existing session if still alive. Parameters: None Returns: 
{
  "sessionId": "string",
  "message": "Browser launched or Connected to <url>"
}
Errors: None Example: 
browser_start

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browser_end

Close the active browser session and release resources. Parameters: None Returns: 
"Session <id> closed."
Errors:
  • No active session (returns "No active session to close." instead of error)
Example: 
browser_end

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Navigation and page state

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browser_navigate

Navigate the browser to a URL. Waits for the page to reach domcontentloaded state. Parameters:
  • url (string, required): The URL to navigate to
Returns: 
{
  "url": "https://example.com",
  "title": "Example Domain"
}
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Navigation timeout after 30 seconds
Example: 
browser_navigate?url=https://example.com

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browser_get_info

Get current page metadata including URL, title, and viewport size. Parameters: None Returns: 
{
  "url": "https://example.com",
  "title": "Example Domain",
  "viewport": { "width": 1280, "height": 720 }
}
Errors:
  • No active session (error: "No active session. Call browser_start first.")
Example: 
browser_get_info

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browser_wait_for

Wait for an element to reach a specific state before proceeding. Useful for dynamic content loading, spinners, or async UI updates. Parameters:
  • selector (string, required): CSS selector to wait for
  • state (string, optional): Element state to wait for (default: "visible")
    • "attached" - Element is present in the DOM (may not be visible)
    • "visible" - Element is in DOM and visible to the user
    • "hidden" - Element is either hidden or removed from DOM
  • timeout (number, optional): Maximum wait time in milliseconds (default: 10000)
Returns: 
"<selector> is now <state>."
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Timeout exceeded before element reached target state
Example: 
browser_wait_for?selector=.loading&state=hidden&timeout=5000

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Interaction

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browser_click

Click an element on the page. Parameters:
  • selector (string, required): CSS selector of the element to click
Returns: 
"Clicked: button.submit"
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Element not found (timeout after 10 seconds)
  • Element is obscured and not clickable
Example: 
browser_click?selector=button[type="submit"]

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browser_fill

Clear and fill an input field directly. Does not trigger keyboard events. Use this for fast form filling without simulating keystrokes. Parameters:
  • selector (string, required): CSS selector of the input field
  • value (string, required): The value to fill
Returns: 
"Filled #email with: user@example.com"
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Element not found or not an input field (timeout after 10 seconds)
Example: 
browser_fill?selector=#email&value=user@example.com

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browser_type

Type text character by character with keyboard events. Clicks the element first to focus. Use this when you need to trigger JavaScript input handlers or autocomplete. Parameters:
  • selector (string, required): CSS selector of the element (will be clicked to focus first)
  • text (string, required): Text to type
  • delay (number, optional): Delay in milliseconds between keystrokes (default: 50)
Returns: 
"Typed \"Hello World\" into #message"
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Element not found (timeout after 10 seconds)
Example: 
browser_type?selector=#message&text=Hello+World&delay=100

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browser_select

Select an option in a <select> dropdown element. Parameters:
  • selector (string, required): CSS selector of the <select> element
  • value (string, required): Value of the option to select (matches the option’s value attribute)
Returns: 
"Selected \"us\" in #country"
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Element not found or not a select element (timeout after 10 seconds)
  • Option value not found in dropdown
Example: 
browser_select?selector=#country&value=us

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browser_hover

Hover the mouse over an element. Useful for triggering dropdown menus, tooltips, or hover effects. Parameters:
  • selector (string, required): CSS selector of the element to hover over
Returns: 
"Hovered over .menu-item"
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Element not found (timeout after 10 seconds)
Example: 
browser_hover?selector=.menu-item

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browser_scroll

Scroll the page or a specific element. Parameters:
  • direction (string, required): Scroll direction
    • "up" - Scroll up by specified pixels
    • "down" - Scroll down by specified pixels
    • "top" - Jump to the top of page/element
    • "bottom" - Jump to the bottom of page/element
  • amount (number, optional): Pixels to scroll for "up"/"down" (default: 500)
  • selector (string, optional): CSS selector of element to scroll (defaults to page)
Returns: 
"Scrolled down by 500px"
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Element not found when selector is specified
Examples: 
# Scroll down
browser_scroll?direction=down&amount=300

# Scroll to top
browser_scroll?direction=top

# Scroll specific element
browser_scroll?direction=bottom&selector=#sidebar

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Observation and extraction

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browser_screenshot

Take a screenshot of the current page or a specific element. Returns a base64-encoded PNG image. Parameters:
  • fullPage (boolean, optional): Capture full scrollable page (default: false, viewport only)
  • selector (string, optional): CSS selector of element to screenshot
Returns: Base64-encoded PNG image (MIME type: image/png) Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Element not found when selector is specified
Examples: 
# Viewport screenshot
browser_screenshot

# Full page screenshot
browser_screenshot?fullPage=true

# Element screenshot
browser_screenshot?selector=header

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browser_get_content

Extract text or HTML content from the page. Useful for data extraction and reading page content. Parameters:
  • type (string, optional): Content type to extract (default: "text")
    • "text" - Visible text content
    • "html" - Raw HTML markup
  • selector (string, optional): CSS selector to scope extraction (defaults to full page)
Returns: Extracted content as text (truncated to 100,000 characters if too large) Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Element not found when selector is specified
Examples: 
# Get all page text
browser_get_content?type=text

# Get HTML of specific element
browser_get_content?type=html&selector=main

# Get text from element
browser_get_content?selector=h1

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browser_evaluate

Execute JavaScript code in the browser page context. Use for extracting structured data, accessing browser APIs, or performing complex operations not available through other tools. Parameters:
  • script (string, required): JavaScript code to execute (use arrow function for expressions: () => document.title)
Returns: Result of the evaluation (JSON-serializable), returned as text (JSON formatted if object/array) Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • JavaScript execution error (syntax error, runtime error, etc.)
Examples: 
# Get page title
browser_evaluate?script=document.title

# Extract structured data
browser_evaluate?script=Array.from(document.querySelectorAll('a')).map(a=>({text:a.innerText,href:a.href}))

# Get computed style
browser_evaluate?script=getComputedStyle(document.body).backgroundColor

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Tab management

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browser_new_tab

Open a new browser tab and optionally navigate to a URL. Automatically switches to the new tab. Parameters:
  • url (string, optional): URL to navigate to in the new tab
Returns: 
{
  "url": "https://example.com",
  "title": "Example Domain",
  "tabsCount": 2
}
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Navigation timeout if url is specified
Example: 
browser_new_tab?url=https://example.com

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browser_list_tabs

List all open tabs in the current browser session. Parameters: None Returns: 
[
  {"index": 0, "url": "https://example.com", "title": "Example", "isActive": false},
  {"index": 1, "url": "https://google.com", "title": "Google", "isActive": true}
]
Errors:
  • No active session (error: "No active session. Call browser_start first.")
Example: 
browser_list_tabs

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browser_switch_tab

Switch to a different tab by index. Parameters:
  • index (number, required): Tab index (0-based, as shown by browser_list_tabs)
Returns: 
{
  "url": "https://example.com",
  "title": "Example Domain",
  "index": 0
}
Errors:
  • No active session (error: "No active session. Call browser_start first.")
  • Tab index out of range (error: "Tab index <n> out of range (0-<max>)")
Example: 
browser_switch_tab?index=0

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Shader and animation control

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browser_disable_shaders

Inject a script that blocks WebGL, throttles requestAnimationFrame, and freezes CSS animations. Use on heavy shader-rendered pages (Three.js, WebGL dashboards) to reduce GPU load. Call BEFORE navigating to the target page for best results. Parameters:
  • webgl (boolean, optional): Block WebGL context creation (default: true)
  • animations (boolean, optional): Freeze CSS animations and transitions (default: true)
  • raf (boolean, optional): Throttle requestAnimationFrame to ~1 FPS (default: true)
Returns: 
{
  "message": "Shader killer injected: WebGL blocked, requestAnimationFrame throttled, CSS animations frozen",
  "disabled": ["WebGL blocked", "requestAnimationFrame throttled to ~1 FPS", "CSS animations/transitions frozen"]
}
Errors:
  • No active session (error: "No active session. Call browser_start first.")
Example: 
browser_disable_shaders?webgl=true&animations=true&raf=true

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browser_restore_shaders

Restore WebGL, requestAnimationFrame, and CSS animations that were disabled by browser_disable_shaders. Removes the injected style element. Note: WebGL and RAF require page reload for full restoration. Parameters: None Returns: 
{
  "message": "Restored: CSS animations restored; WebGL requires page reload to fully restore",
  "note": "For full WebGL/RAF restoration, navigate or reload the page."
}
Errors:
  • No active session (error: "No active session. Call browser_start first.")
Example: 
browser_restore_shaders

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Practical guidance

  • Prefer browser_fill over browser_type for form inputs unless you need keyboard events
  • Use browser_wait_for on dynamic pages before clicking or filling elements
  • Use browser_get_content for data extraction; use screenshots for visual verification
  • Call browser_disable_shaders before navigation for best results on heavy pages
  • Always call browser_end when done to free resources
  • Use browser_list_tabs to check tab state before switching in multi-tab workflows