browser-automation（浏览器自动化）

Browser Automation

Control a real Chrome browser through MCP tools. The browser launches automatically on first use via a background daemon -- no API keys required for local mode.

Available Tools

Core Workflow

Every browser task follows this loop:

1. Navigate to the target URL with browser_navigate
2. Snapshot the page with browser_snapshot to get the accessibility tree with element refs
3. Act using browser_click, browser_fill, browser_press, browser_select with the refs from the snapshot
4. Verify with browser_screenshot to confirm the action worked
5. Repeat steps 2-4 until the task is complete
6. Close the browser with browser_close when done

How Element Refs Work

Call browser_snapshot -- it returns an accessibility tree where every interactive element has a ref like [0-5]. Use that ref to target the element.

RootWebArea "Example" url="https://example.com"
  [0-0] link "Home"
  [0-1] link "About"
  [0-2] button "Sign In"
  [0-5] textbox "Search"

Then act on elements using their ref:

browser_click({ ref: "@0-2" })        → clicks "Sign In"
browser_fill({ ref: "@0-5", value: "my query" })  → fills the search box

Refs are more reliable than CSS selectors because they're tied to the accessibility tree and work across iframes.

Ref formats (all equivalent)

• @0-5 -- @ prefix
• 0-5 -- plain ref
• ref=0-5 -- explicit prefix

Snapshot also provides maps

The full snapshot output includes:

• xpathMap: Cross-frame XPath selectors
• cssMap: CSS selectors when available
• urlMap: URLs extracted from links

Use the compact flag (-c) for a concise tree without the maps.

Common Patterns

Fill out a form

1. browser_navigate({ url: "https://example.com/signup" })
2. browser_snapshot()
   → Find refs: [0-3] textbox "Email", [0-4] textbox "Password", [0-7] button "Submit"
3. browser_fill({ ref: "@0-3", value: "user@example.com" })
4. browser_fill({ ref: "@0-4", value: "securepassword" })
5. browser_click({ ref: "@0-7" })
6. browser_screenshot()  → Verify success

Extract data from a page

1. browser_navigate({ url: "https://example.com/products" })
2. browser_evaluate({ script: "JSON.stringify(Array.from(document.querySelectorAll('.product')).map(el => ({ name: el.querySelector('h2')?.textContent, price: el.querySelector('.price')?.textContent })))" })

Handle pagination

1. browser_navigate({ url: "https://example.com/results" })
2. browser_evaluate({ script: "..." })  → Extract data from page 1
3. browser_snapshot()  → Find the "Next" button ref
4. browser_click({ ref: "@0-12" })
5. browser_wait({ type: "load" })
6. browser_evaluate({ script: "..." })  → Extract data from page 2

Deal with elements not in view

1. browser_snapshot()  → Target element not found
2. browser_scroll({ x: 0, y: 0, deltaX: 0, deltaY: 500 })
3. browser_snapshot()  → Now the element appears
4. browser_click({ ref: "@0-8" })

Wait for dynamic content

1. browser_click({ ref: "@0-3" })
2. browser_wait({ type: "selector", value: ".new-content", timeout: 10000 })
3. browser_snapshot()  → New elements available

Multi-tab workflow

1. browser_navigate({ url: "https://example.com" })
2. browser_new_tab({ url: "https://other.com" })
3. browser_pages()  → See tab indices
4. browser_switch_tab({ index: 0 })  → Back to first tab
5. browser_close_tab({ index: 1 })  → Close second tab

Keyboard shortcuts

1. browser_press({ key: "Cmd+A" })     → Select all
2. browser_press({ key: "Cmd+C" })     → Copy
3. browser_press({ key: "Tab" })       → Move to next field
4. browser_press({ key: "Enter" })     → Submit
5. browser_press({ key: "Escape" })    → Close modal

Network inspection

1. browser_network({ action: "on" })     → Start capturing
2. browser_navigate({ url: "https://api.example.com" })
3. browser_network({ action: "path" })   → Get capture directory
4. browser_network({ action: "off" })    → Stop capturing

Error Recovery

• Element not found: Call browser_snapshot again -- the page may have changed. Refs update on each snapshot.
• Page not loaded: Use browser_wait({type: "load"}) before interacting.
• Click intercepted: Another element is covering the target. Scroll or close modals first.
• Timeout: Increase the timeout parameter or check if the page requires interaction first.
• Stale page: After navigation or form submission, always snapshot again before acting.
• Daemon crashed: Commands self-heal -- the daemon auto-restarts on the next command.

Tips

• Always navigate first before any other interaction.
• Always snapshot before acting to get current refs -- refs change when the page changes.
• Take screenshots after key actions to verify state.
• Use refs, not CSS selectors -- they are more reliable across iframes and dynamic pages.
• Use browser_fill for form inputs -- it's designed for input fields and presses Enter by default.
• Use browser_type for raw text -- goes to the currently focused element.
• Use browser_press for keyboard shortcuts -- Enter, Tab, Escape, Cmd+A, etc.
• Close the browser when done to free system resources.
• Use browser_evaluate for bulk extraction -- it's faster than scraping element by element.
• Use browser_get for quick info -- url, title, text, html, value, box without a full snapshot.

Environment Modes

The browser tools automatically detect which mode to use. No code changes or extra configuration from the model is needed -- just call the tools normally. The same tools work identically in both modes.

• Local (default): Uses the user's installed Chrome. No API keys needed. A background daemon manages the browser lifecycle.
• Browserbase cloud: Activates automatically when a .env file in the plugin root contains BROWSERBASE_API_KEY and BROWSERBASE_PROJECT_ID. Provides stealth browsing, proxy support, and CAPTCHA solving. The CLI wrapper creates a cloud session and connects the daemon via WebSocket.

The model should NEVER try to configure credentials or environment variables. If the user wants to switch modes, they edit the .env file themselves.