MCP Tools Reference

The BAP MCP server exposes 23 tools organized into six categories. With --slim mode, only 5 essential tools are exposed.

navigate

Navigate to a URL. Supports fused observation via the observe parameter.

string

required

The URL to navigate to.

string

default:"load"

When to consider navigation complete: load, domcontentloaded, networkidle.

object

Fuse observation with navigation. Returns page elements alongside the navigation result.

number

default:"50"

Maximum number of elements to return.

string

Response tier: full, interactive, minimal.

navigate({ url: "https://example.com", observe: { maxElements: 20 } })

go_back

Navigate back in browser history.No parameters.

go_forward

Navigate forward in browser history.No parameters.

reload

Reload the current page.No parameters.

Element Interaction

click

Click an element using semantic selectors.

string

required

Element selector (see Selector Formats below).

fill

Fill a form field. Clears existing content first.

string

required

Element selector targeting the input field.

string

required

The value to fill.

type

Type text character by character. First clicks the element, then types. Triggers individual key events.

string

required

Element selector.

string

required

Text to type character by character.

number

Delay in milliseconds between keystrokes.

press

Press keyboard keys (Enter, Tab, shortcuts).

string

required

Key to press (e.g., Enter, Tab, Escape, Control+a).

string

Optional element to focus before pressing.

select

Select an option from a dropdown.

string

required

Element selector targeting the <select> element.

string

required

Option value or visible text to select.

scroll

Scroll the page or a specific element.

string

default:"down"

Scroll direction: up, down, left, right.

number

default:"300"

Pixels to scroll.

string

Optional element to scroll into view.

hover

Hover over an element.

string

required

Element selector.

Observation

observe

AI-optimized page observation. Returns interactive elements with stable refs. Supports incremental diffs and response tiers.

number

default:"50"

Maximum elements to return.

string[]

Filter by ARIA roles (e.g., ["button", "link", "textbox"]).

boolean

default:"false"

Include an annotated screenshot with element refs.

boolean

default:"false"

Return only changes since the last observation: { added, updated, removed }.

string

Response tier: full, interactive, minimal.

boolean

default:"false"

Include tools discovered via the WebMCP standard.

observe({ maxElements: 20, responseTier: "interactive", includeScreenshot: true })

screenshot

Take a screenshot of the current page.

boolean

default:"false"

Capture the entire scrollable page.

aria_snapshot

Token-efficient YAML accessibility snapshot. Approximately 80% fewer tokens than accessibility.No parameters.

Prefer aria_snapshot over accessibility for cost efficiency. Same structure, far fewer tokens.

accessibility

Full accessibility tree.No parameters.

content

Get page text content.

string

default:"text"

Output format: text or markdown.

element

Query element properties: exists, visible, enabled, checked, value.

string

required

Element selector.

AI Agent Methods

act

Execute a sequence of browser actions in a single call. Supports fused pre/post observation.

array

required

Array of action steps. Each step has action, selector, and optionally value.

steps: [
  { action: "action/fill", selector: "label:Email", value: "user@example.com" },
  { action: "action/click", selector: "role:button:Submit" }
]

object

Observe page state before executing steps.

object

Observe page state after executing steps. Contains maxElements, responseTier.

act({
  steps: [
    { action: "action/fill", selector: "@e1", value: "user@example.com" },
    { action: "action/fill", selector: "@e2", value: "password123" },
    { action: "action/click", selector: "role:button:Sign in" }
  ],
  postObserve: { responseTier: "interactive" }
})

extract

Extract structured data from the page using schema and CSS heuristics.

string

Natural language description of what to extract.

string

Extraction mode: single (one object) or list (array of objects).

object

JSON Schema defining the extraction shape.

extract({
  instruction: "Extract product listings",
  mode: "list",
  schema: {
    type: "array",
    items: {
      type: "object",
      properties: {
        name: { type: "string" },
        price: { type: "number" }
      }
    }
  }
})

Page Management

pages

List all open pages/tabs.No parameters.

activate_page

Switch to a different page/tab.

string

required

Page ID from the pages result.

close_page

Close the current page/tab.No parameters.

Discovery

discover_tools

Discover tools that websites expose via the W3C WebMCP standard. Checks for declarative (form-based) and imperative (navigator.modelContext) tool definitions.No parameters.

Selector Formats

All tools that accept a selector parameter support these formats:

role:button:Submit        # ARIA role + accessible name (recommended)
text:Sign in              # Visible text content
label:Email address       # Associated label
testid:submit-button      # data-testid attribute
ref:@submitBtn            # Stable element reference from observe
css:.btn-primary          # CSS selector (fallback)
xpath://button[@type]     # XPath selector (fallback)

Always prefer role: selectors for buttons, links, and inputs. They survive DOM changes. Never copy CSS selectors from browser DevTools.

Resources

The MCP server also exposes 4 resources:

Resource	Description
`bap://page/state`	Current page URL and title
`bap://page/accessibility`	Full accessibility tree
`bap://page/aria-snapshot`	YAML accessibility snapshot
`bap://page/screenshot`	Current page screenshot

​MCP Tools Reference

​Navigation

​Element Interaction

​Observation

​AI Agent Methods

​Page Management

​Discovery

​Selector Formats

​Resources

MCP Tools Reference

Navigation

Element Interaction

Observation

AI Agent Methods

Page Management

Discovery

Selector Formats

Resources