surf-cli Codebase

Architecture

cli.cjs --socket:/tmp/surf.sock--> host.cjs --native-msg--> service-worker/index.ts --CDP/chrome-APIs--> browser

Add CLI Command

1. Add to TOOLS in native/cli.cjs:158 (args, opts, examples)
2. Add handler in src/service-worker/index.ts:50 handleMessage() switch
3. CDP op? → add method src/cdp/controller.ts:60
4. DOM interaction? → add handler src/content/accessibility-tree.ts:99

Add CDP Operation

1. Add method to CDPController class src/cdp/controller.ts:60
2. Use this.send(tabId, "Domain.method", params)
3. Handle events in handleCDPEvent() if needed

Core Files

src/service-worker/index.ts (~2500L) - Central msg router, CDP ops, screenshot cache, tab registry

• Msg types: EXECUTE_CLICK, EXECUTE_TYPE, READ_PAGE, EXECUTE_SCREENSHOT
• Screenshot cache: generateScreenshotId(), cacheScreenshot(), getScreenshot()
• Tab names: tabNameRegistry Map<name,tabId>

src/cdp/controller.ts (~1000L) - CDP wrapper, CDPController class

• Mouse: click(), rightClick(), doubleClick(), hover(), drag()
• Keyboard: type(), pressKey(), pressKeyChord()
• Screenshots: captureScreenshot(), captureRegion()
• Network/Console: enableNetworkTracking(), getNetworkRequests(), getResponseBody(), subscribeToNetwork(), enableConsoleTracking(), getConsoleMessages()
• Emulation: emulateNetwork(), emulateCPU(), emulateGeolocation()

src/content/accessibility-tree.ts (~1900L) - Content script, generates a11y tree YAML, element interactions

• Handlers: GENERATE_ACCESSIBILITY_TREE, CLICK_ELEMENT, FORM_INPUT, GET_ELEMENT_COORDINATES, WAIT_FOR_ELEMENT, WAIT_FOR_URL
• Element refs: e1, e2... in window.__piRefs for stable references

native/cli.cjs (~2100L) - CLI parser, socket client

• TOOLS: command defs with args/opts
• ALIASES: shortcut→command map
• AUTO_SCREENSHOT_TOOLS: commands that auto-capture
• parseArgs(), sendRequest()

native/host.cjs (~2100L) - Socket server, AI integration

• handleToolRequest(): main dispatcher
• mapToolToMessage(): tool→extension msg converter
• queueAiRequest(): AI request serialization
• AI clients: chatgptClient, geminiClient, perplexityClient

src/native/port-manager.ts - Extension↔native messaging, auto-reconnect, request/response tracking

Message Flow

1. CLI: surf click e5
2. cli.cjs parses → socket → host.cjs
3. host.cjs routes to EXECUTE_CLICK msg
4. Native msg → service-worker/index.ts
5. Service worker: CDP (cdp/controller.ts) or content script (chrome.tabs.sendMessage)
6. Response flows back to CLI

Debug

• Extension logs: chrome://extensions → Service Worker → Console
• Host logs: /tmp/surf-host.log
• CLI raw output: --json flag

Test

npm run build            # Build ext
npm test                 # Run tests
npm run test:coverage    # Coverage

Element Refs

A11y tree assigns e1, e2... during READ_PAGE. Stored window.__piRefs. Reset each read command.

Network Capture

• CDP captures via Network.* events cdp/controller.ts:73
• Storage: /tmp/surf/requests.jsonl
• Formatters: native/formatters/network.cjs:259

Build/Install

npm run dev              # Watch mode
npm run build            # Prod → dist/
# Load dist/ as unpacked ext
surf install             # Register native host; prints the dist/ folder to load

Gotchas

• CDP attach: 100-500ms first time/tab
• chrome:// pages restricted
• Content script needs page refresh on existing tabs
• Screenshots auto-resize 1200px unless --full