Add browse tool support.
I reviewed some MCPs (using OpenAI's deep research to help), and it
helped me choose chromedp as the relevant library and helped me come up
with an interface. This commit adds chrome to the Docker image which is
kind of big. (I've noticed that it's smaller on Ubuntu, where it doesn't
pull in X11.) go-playwright was a library contender as well.
Implement browser automation tooling using chromedp
This implementation adds browser automation capabilities to the system via the chromedp library,
enabling Claude to interact with web content effectively.
Key features include:
1. Core browser automation functionality:
- Created new browsertools package in claudetool/browser
- Implemented tools for navigating, clicking, typing, waiting for elements,
getting text, evaluating JavaScript, taking screenshots, and scrolling
- Added lazy browser initialization that defers until first use
- Integrated with the agent to expose these tools to Claude
2. Screenshot handling and display:
- Implemented screenshot storage with UUID-based IDs in /tmp/sketch-screenshots
- Added endpoint to serve screenshots via /screenshot/{id}
- Created dedicated UI component for displaying screenshots
- Ensured proper responsive design with loading states and error handling
- Fixed URL paths for proper rehomed URL support
- Modified tool calls component to auto-expand screenshot results
3. Error handling and reliability:
- Added graceful error handling for browser initialization failures
- Implemented proper cleanup of browser resources
The browser automation tools provide a powerful way for Claude to interact with web content,
making it possible to scrape data, test web applications, and automate web-based tasks.
Co-Authored-By: sketch <hello@sketch.dev>
diff --git a/claudetool/browse/browse.go b/claudetool/browse/browse.go
new file mode 100644
index 0000000..a76cd24
--- /dev/null
+++ b/claudetool/browse/browse.go
@@ -0,0 +1,633 @@
+// Package browse provides browser automation tools for the agent
+package browse
+
+import (
+ "context"
+ "encoding/json"
+ "fmt"
+ "log"
+ "os"
+ "path/filepath"
+ "sync"
+ "time"
+
+ "github.com/chromedp/chromedp"
+ "github.com/google/uuid"
+ "sketch.dev/llm"
+)
+
+// ScreenshotDir is the directory where screenshots are stored
+const ScreenshotDir = "/tmp/sketch-screenshots"
+
+// BrowseTools contains all browser tools and manages a shared browser instance
+type BrowseTools struct {
+ ctx context.Context
+ cancel context.CancelFunc
+ browserCtx context.Context
+ browserCtxCancel context.CancelFunc
+ mux sync.Mutex
+ initOnce sync.Once
+ initialized bool
+ initErr error
+ // Map to track screenshots by ID and their creation time
+ screenshots map[string]time.Time
+ screenshotsMutex sync.Mutex
+}
+
+// NewBrowseTools creates a new set of browser automation tools
+func NewBrowseTools(ctx context.Context) *BrowseTools {
+ ctx, cancel := context.WithCancel(ctx)
+
+ // Ensure the screenshot directory exists
+ if err := os.MkdirAll(ScreenshotDir, 0755); err != nil {
+ log.Printf("Failed to create screenshot directory: %v", err)
+ }
+
+ b := &BrowseTools{
+ ctx: ctx,
+ cancel: cancel,
+ screenshots: make(map[string]time.Time),
+ }
+
+ return b
+}
+
+// Initialize starts the browser if it's not already running
+func (b *BrowseTools) Initialize() error {
+ b.mux.Lock()
+ defer b.mux.Unlock()
+
+ b.initOnce.Do(func() {
+ // ChromeDP.ExecPath has a list of common places to find Chrome...
+ opts := chromedp.DefaultExecAllocatorOptions[:]
+ allocCtx, _ := chromedp.NewExecAllocator(b.ctx, opts...)
+ browserCtx, browserCancel := chromedp.NewContext(
+ allocCtx,
+ chromedp.WithLogf(log.Printf),
+ )
+
+ b.browserCtx = browserCtx
+ b.browserCtxCancel = browserCancel
+
+ // Ensure the browser starts
+ if err := chromedp.Run(browserCtx); err != nil {
+ b.initErr = fmt.Errorf("failed to start browser (please apt get chromium or equivalent): %w", err)
+ return
+ }
+ b.initialized = true
+ })
+
+ return b.initErr
+}
+
+// Close shuts down the browser
+func (b *BrowseTools) Close() {
+ b.mux.Lock()
+ defer b.mux.Unlock()
+
+ if b.browserCtxCancel != nil {
+ b.browserCtxCancel()
+ b.browserCtxCancel = nil
+ }
+
+ if b.cancel != nil {
+ b.cancel()
+ }
+
+ b.initialized = false
+ log.Println("Browser closed")
+}
+
+// GetBrowserContext returns the context for browser operations
+func (b *BrowseTools) GetBrowserContext() (context.Context, error) {
+ if err := b.Initialize(); err != nil {
+ return nil, err
+ }
+ return b.browserCtx, nil
+}
+
+// All tools return this as a response when successful
+type baseResponse struct {
+ Status string `json:"status,omitempty"`
+}
+
+func successResponse() string {
+ return `{"status":"success"}`
+}
+
+func errorResponse(err error) string {
+ return fmt.Sprintf(`{"status":"error","error":"%s"}`, err.Error())
+}
+
+// NavigateTool definition
+type navigateInput struct {
+ URL string `json:"url"`
+}
+
+// NewNavigateTool creates a tool for navigating to URLs
+func (b *BrowseTools) NewNavigateTool() *llm.Tool {
+ return &llm.Tool{
+ Name: "browser_navigate",
+ Description: "Navigate the browser to a specific URL and wait for page to load",
+ InputSchema: json.RawMessage(`{
+ "type": "object",
+ "properties": {
+ "url": {
+ "type": "string",
+ "description": "The URL to navigate to"
+ }
+ },
+ "required": ["url"]
+ }`),
+ Run: b.navigateRun,
+ }
+}
+
+func (b *BrowseTools) navigateRun(ctx context.Context, m json.RawMessage) (string, error) {
+ var input navigateInput
+ if err := json.Unmarshal(m, &input); err != nil {
+ return errorResponse(fmt.Errorf("invalid input: %w", err)), nil
+ }
+
+ browserCtx, err := b.GetBrowserContext()
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ err = chromedp.Run(browserCtx,
+ chromedp.Navigate(input.URL),
+ chromedp.WaitReady("body"),
+ )
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ return successResponse(), nil
+}
+
+// ClickTool definition
+type clickInput struct {
+ Selector string `json:"selector"`
+ WaitVisible bool `json:"wait_visible,omitempty"`
+}
+
+// NewClickTool creates a tool for clicking elements
+func (b *BrowseTools) NewClickTool() *llm.Tool {
+ return &llm.Tool{
+ Name: "browser_click",
+ Description: "Click the first element matching a CSS selector",
+ InputSchema: json.RawMessage(`{
+ "type": "object",
+ "properties": {
+ "selector": {
+ "type": "string",
+ "description": "CSS selector for the element to click"
+ },
+ "wait_visible": {
+ "type": "boolean",
+ "description": "Wait for the element to be visible before clicking"
+ }
+ },
+ "required": ["selector"]
+ }`),
+ Run: b.clickRun,
+ }
+}
+
+func (b *BrowseTools) clickRun(ctx context.Context, m json.RawMessage) (string, error) {
+ var input clickInput
+ if err := json.Unmarshal(m, &input); err != nil {
+ return errorResponse(fmt.Errorf("invalid input: %w", err)), nil
+ }
+
+ browserCtx, err := b.GetBrowserContext()
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ actions := []chromedp.Action{
+ chromedp.WaitReady(input.Selector),
+ }
+
+ if input.WaitVisible {
+ actions = append(actions, chromedp.WaitVisible(input.Selector))
+ }
+
+ actions = append(actions, chromedp.Click(input.Selector))
+
+ err = chromedp.Run(browserCtx, actions...)
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ return successResponse(), nil
+}
+
+// TypeTool definition
+type typeInput struct {
+ Selector string `json:"selector"`
+ Text string `json:"text"`
+ Clear bool `json:"clear,omitempty"`
+}
+
+// NewTypeTool creates a tool for typing into input elements
+func (b *BrowseTools) NewTypeTool() *llm.Tool {
+ return &llm.Tool{
+ Name: "browser_type",
+ Description: "Type text into an input or textarea element",
+ InputSchema: json.RawMessage(`{
+ "type": "object",
+ "properties": {
+ "selector": {
+ "type": "string",
+ "description": "CSS selector for the input element"
+ },
+ "text": {
+ "type": "string",
+ "description": "Text to type into the element"
+ },
+ "clear": {
+ "type": "boolean",
+ "description": "Clear the input field before typing"
+ }
+ },
+ "required": ["selector", "text"]
+ }`),
+ Run: b.typeRun,
+ }
+}
+
+func (b *BrowseTools) typeRun(ctx context.Context, m json.RawMessage) (string, error) {
+ var input typeInput
+ if err := json.Unmarshal(m, &input); err != nil {
+ return errorResponse(fmt.Errorf("invalid input: %w", err)), nil
+ }
+
+ browserCtx, err := b.GetBrowserContext()
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ actions := []chromedp.Action{
+ chromedp.WaitReady(input.Selector),
+ chromedp.WaitVisible(input.Selector),
+ }
+
+ if input.Clear {
+ actions = append(actions, chromedp.Clear(input.Selector))
+ }
+
+ actions = append(actions, chromedp.SendKeys(input.Selector, input.Text))
+
+ err = chromedp.Run(browserCtx, actions...)
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ return successResponse(), nil
+}
+
+// WaitForTool definition
+type waitForInput struct {
+ Selector string `json:"selector"`
+ TimeoutMS int `json:"timeout_ms,omitempty"`
+}
+
+// NewWaitForTool creates a tool for waiting for elements
+func (b *BrowseTools) NewWaitForTool() *llm.Tool {
+ return &llm.Tool{
+ Name: "browser_wait_for",
+ Description: "Wait for an element to be present in the DOM",
+ InputSchema: json.RawMessage(`{
+ "type": "object",
+ "properties": {
+ "selector": {
+ "type": "string",
+ "description": "CSS selector for the element to wait for"
+ },
+ "timeout_ms": {
+ "type": "integer",
+ "description": "Maximum time to wait in milliseconds (default: 30000)"
+ }
+ },
+ "required": ["selector"]
+ }`),
+ Run: b.waitForRun,
+ }
+}
+
+func (b *BrowseTools) waitForRun(ctx context.Context, m json.RawMessage) (string, error) {
+ var input waitForInput
+ if err := json.Unmarshal(m, &input); err != nil {
+ return errorResponse(fmt.Errorf("invalid input: %w", err)), nil
+ }
+
+ timeout := 30000 // default timeout 30 seconds
+ if input.TimeoutMS > 0 {
+ timeout = input.TimeoutMS
+ }
+
+ browserCtx, err := b.GetBrowserContext()
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ timeoutCtx, cancel := context.WithTimeout(browserCtx, time.Duration(timeout)*time.Millisecond)
+ defer cancel()
+
+ err = chromedp.Run(timeoutCtx, chromedp.WaitReady(input.Selector))
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ return successResponse(), nil
+}
+
+// GetTextTool definition
+type getTextInput struct {
+ Selector string `json:"selector"`
+}
+
+type getTextOutput struct {
+ Text string `json:"text"`
+}
+
+// NewGetTextTool creates a tool for getting text from elements
+func (b *BrowseTools) NewGetTextTool() *llm.Tool {
+ return &llm.Tool{
+ Name: "browser_get_text",
+ Description: "Get the innerText of an element",
+ InputSchema: json.RawMessage(`{
+ "type": "object",
+ "properties": {
+ "selector": {
+ "type": "string",
+ "description": "CSS selector for the element to get text from"
+ }
+ },
+ "required": ["selector"]
+ }`),
+ Run: b.getTextRun,
+ }
+}
+
+func (b *BrowseTools) getTextRun(ctx context.Context, m json.RawMessage) (string, error) {
+ var input getTextInput
+ if err := json.Unmarshal(m, &input); err != nil {
+ return errorResponse(fmt.Errorf("invalid input: %w", err)), nil
+ }
+
+ browserCtx, err := b.GetBrowserContext()
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ var text string
+ err = chromedp.Run(browserCtx,
+ chromedp.WaitReady(input.Selector),
+ chromedp.Text(input.Selector, &text),
+ )
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ output := getTextOutput{Text: text}
+ result, err := json.Marshal(output)
+ if err != nil {
+ return errorResponse(fmt.Errorf("failed to marshal response: %w", err)), nil
+ }
+
+ return string(result), nil
+}
+
+// EvalTool definition
+type evalInput struct {
+ Expression string `json:"expression"`
+}
+
+type evalOutput struct {
+ Result any `json:"result"`
+}
+
+// NewEvalTool creates a tool for evaluating JavaScript
+func (b *BrowseTools) NewEvalTool() *llm.Tool {
+ return &llm.Tool{
+ Name: "browser_eval",
+ Description: "Evaluate JavaScript in the browser context",
+ InputSchema: json.RawMessage(`{
+ "type": "object",
+ "properties": {
+ "expression": {
+ "type": "string",
+ "description": "JavaScript expression to evaluate"
+ }
+ },
+ "required": ["expression"]
+ }`),
+ Run: b.evalRun,
+ }
+}
+
+func (b *BrowseTools) evalRun(ctx context.Context, m json.RawMessage) (string, error) {
+ var input evalInput
+ if err := json.Unmarshal(m, &input); err != nil {
+ return errorResponse(fmt.Errorf("invalid input: %w", err)), nil
+ }
+
+ browserCtx, err := b.GetBrowserContext()
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ var result any
+ err = chromedp.Run(browserCtx, chromedp.Evaluate(input.Expression, &result))
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ output := evalOutput{Result: result}
+ response, err := json.Marshal(output)
+ if err != nil {
+ return errorResponse(fmt.Errorf("failed to marshal response: %w", err)), nil
+ }
+
+ return string(response), nil
+}
+
+// ScreenshotTool definition
+type screenshotInput struct {
+ Selector string `json:"selector,omitempty"`
+ Format string `json:"format,omitempty"`
+}
+
+type screenshotOutput struct {
+ ID string `json:"id"`
+}
+
+// NewScreenshotTool creates a tool for taking screenshots
+func (b *BrowseTools) NewScreenshotTool() *llm.Tool {
+ return &llm.Tool{
+ Name: "browser_screenshot",
+ Description: "Take a screenshot of the page or a specific element",
+ InputSchema: json.RawMessage(`{
+ "type": "object",
+ "properties": {
+ "selector": {
+ "type": "string",
+ "description": "CSS selector for the element to screenshot (optional)"
+ },
+ "format": {
+ "type": "string",
+ "description": "Output format ('base64' or 'png'), defaults to 'base64'",
+ "enum": ["base64", "png"]
+ }
+ }
+ }`),
+ Run: b.screenshotRun,
+ }
+}
+
+func (b *BrowseTools) screenshotRun(ctx context.Context, m json.RawMessage) (string, error) {
+ var input screenshotInput
+ if err := json.Unmarshal(m, &input); err != nil {
+ return errorResponse(fmt.Errorf("invalid input: %w", err)), nil
+ }
+
+ browserCtx, err := b.GetBrowserContext()
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ var buf []byte
+ var actions []chromedp.Action
+
+ if input.Selector != "" {
+ // Take screenshot of specific element
+ actions = append(actions,
+ chromedp.WaitReady(input.Selector),
+ chromedp.Screenshot(input.Selector, &buf, chromedp.NodeVisible),
+ )
+ } else {
+ // Take full page screenshot
+ actions = append(actions, chromedp.CaptureScreenshot(&buf))
+ }
+
+ err = chromedp.Run(browserCtx, actions...)
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ // Save the screenshot and get its ID
+ id := b.SaveScreenshot(buf)
+ if id == "" {
+ return errorResponse(fmt.Errorf("failed to save screenshot")), nil
+ }
+
+ // Return the ID in the response
+ output := screenshotOutput{ID: id}
+ response, err := json.Marshal(output)
+ if err != nil {
+ return errorResponse(fmt.Errorf("failed to marshal response: %w", err)), nil
+ }
+
+ return string(response), nil
+}
+
+// ScrollIntoViewTool definition
+type scrollIntoViewInput struct {
+ Selector string `json:"selector"`
+}
+
+// NewScrollIntoViewTool creates a tool for scrolling elements into view
+func (b *BrowseTools) NewScrollIntoViewTool() *llm.Tool {
+ return &llm.Tool{
+ Name: "browser_scroll_into_view",
+ Description: "Scroll an element into view if it's not visible",
+ InputSchema: json.RawMessage(`{
+ "type": "object",
+ "properties": {
+ "selector": {
+ "type": "string",
+ "description": "CSS selector for the element to scroll into view"
+ }
+ },
+ "required": ["selector"]
+ }`),
+ Run: b.scrollIntoViewRun,
+ }
+}
+
+func (b *BrowseTools) scrollIntoViewRun(ctx context.Context, m json.RawMessage) (string, error) {
+ var input scrollIntoViewInput
+ if err := json.Unmarshal(m, &input); err != nil {
+ return errorResponse(fmt.Errorf("invalid input: %w", err)), nil
+ }
+
+ browserCtx, err := b.GetBrowserContext()
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ script := fmt.Sprintf(`
+ const el = document.querySelector('%s');
+ if (el) {
+ el.scrollIntoView({behavior: 'smooth', block: 'center'});
+ return true;
+ }
+ return false;
+ `, input.Selector)
+
+ var result bool
+ err = chromedp.Run(browserCtx,
+ chromedp.WaitReady(input.Selector),
+ chromedp.Evaluate(script, &result),
+ )
+ if err != nil {
+ return errorResponse(err), nil
+ }
+
+ if !result {
+ return errorResponse(fmt.Errorf("element not found: %s", input.Selector)), nil
+ }
+
+ return successResponse(), nil
+}
+
+// GetAllTools returns all browser tools
+func (b *BrowseTools) GetAllTools() []*llm.Tool {
+ return []*llm.Tool{
+ b.NewNavigateTool(),
+ b.NewClickTool(),
+ b.NewTypeTool(),
+ b.NewWaitForTool(),
+ b.NewGetTextTool(),
+ b.NewEvalTool(),
+ b.NewScreenshotTool(),
+ b.NewScrollIntoViewTool(),
+ }
+}
+
+// SaveScreenshot saves a screenshot to disk and returns its ID
+func (b *BrowseTools) SaveScreenshot(data []byte) string {
+ // Generate a unique ID
+ id := uuid.New().String()
+
+ // Save the file
+ filePath := filepath.Join(ScreenshotDir, id+".png")
+ if err := os.WriteFile(filePath, data, 0644); err != nil {
+ log.Printf("Failed to save screenshot: %v", err)
+ return ""
+ }
+
+ // Track this screenshot
+ b.screenshotsMutex.Lock()
+ b.screenshots[id] = time.Now()
+ b.screenshotsMutex.Unlock()
+
+ return id
+}
+
+// GetScreenshotPath returns the full path to a screenshot by ID
+func GetScreenshotPath(id string) string {
+ return filepath.Join(ScreenshotDir, id+".png")
+}