Create SKILL.md for Playwright Go Automation

Added comprehensive guidelines for using Playwright Go for browser automation, including architecture, logging, error handling, and stealth techniques.

skills/go-playwright/SKILL.md

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+---
+name: playwright-go-automation
+description: Expert capability for robust, stealthy, and efficient browser automation using Playwright Go.
+---
+
+# Playwright Go Automation Expert
+
+## Overview
+This skill provides a comprehensive framework for writing high-performance, production-grade browser automation scripts using `github.com/playwright-community/playwright-go`. It enforces architectural best practices (contexts over instances), robust error handling, structured logging (Zap), and advanced human-emulation techniques to bypass anti-bot systems.
+
+## When to Use This Skill
+- Use when the user asks to "scrape," "automate," or "test" a website using Go.
+- Use when the target site has complex dynamic content (SPA, React, Vue) requiring a real browser.
+- Use when the user mentions "stealth," "avoiding detection," "cloudflare," or "human-like" behavior.
+- Use when debugging existing Playwright scripts.
+
+## Strategic Implementation Guidelines
+
+### 1. Architecture: Contexts vs. Browsers
+**CRITICAL:** Never launch a new `Browser` instance for every task.
+- **Pattern:** Launch the `Browser` *once* (singleton). Create a new `BrowserContext` for each distinct session or task.
+- **Why:** Contexts are lightweight and created in milliseconds. Browsers take seconds to launch.
+- **Isolation:** Contexts provide complete isolation (cookies, cache, storage) without the overhead of a new process.
+
+### 2. Logging & Observability
+- **Library:** Use `go.uber.org/zap` exclusively.
+- **Rule:** Do not use `fmt.Println`.
+- **Modes:**
+  - **Dev:** `zap.NewDevelopment()` (Console friendly)
+  - **Prod:** `zap.NewProduction()` (JSON structured)
+- **Traceability:** Log every navigation, click, and input with context fields (e.g., `logger.Info("clicking button", zap.String("selector", sel))`).
+
+### 3. Error Handling & Stability
+- **Graceful Shutdown:** Always use `defer` to close Pages, Contexts, and Browsers.
+- **Panic Recovery:** Wrap critical automation routines in a safe runner that recovers panics and logs the stack trace.
+- **Timeouts:** Never rely on default timeouts. Set explicit timeouts (e.g., `playwright.PageClickOptions{Timeout: playwright.Float(5000)}`).
+
+### 4. Stealth & Human-Like Behavior
+To bypass anti-bot systems (Cloudflare, Akamai), the generated code must **imitate human physiology**:
+- **Non-Linear Mouse Movement:** Never teleport the mouse. Implement a helper that moves the mouse along a Bezier curve with random jitter.
+- **Input Latency:** never use `Fill()`. Use `Type()` with random delays between keystrokes (50ms–200ms).
+- **Viewport Randomization:** Randomize the viewport size slightly (e.g., 1920x1080 ± 15px) to avoid fingerprinting.
+- **Behavioral Noise:** Randomly scroll, focus/unfocus the window, or hover over irrelevant elements ("idling") during long waits.
+- **User-Agent:** Rotate User-Agents for every new Context.
+
+### 5. Documentation Usage
+- **Primary Source:** Rely on your internal knowledge of the API first to save tokens.
+- **Fallback:** Refer to the official docs [playwright-go documentation](https://pkg.go.dev/github.com/playwright-community/playwright-go#section-documentation) ONLY if:
+  - You encounter an unknown error.
+  - You need to implement complex network interception or authentication flows.
+  - The API has changed significantly.
+
+## Code Examples
+
+### Standard Initialization (Headless + Zap)
+```go
+package main
+
+import (
+    "[github.com/playwright-community/playwright-go](https://github.com/playwright-community/playwright-go)"
+    "go.uber.org/zap"
+    "log"
+)
+
+func main() {
+    // 1. Setup Logger
+    logger, _ := zap.NewDevelopment()
+    defer logger.Sync()
+
+    // 2. Start Playwright Driver
+    pw, err := playwright.Run()
+    if err != nil {
+        logger.Fatal("could not start playwright", zap.Error(err))
+    }
+    
+    // 3. Launch Browser (Singleton)
+    // Use Headless: false and SlowMo for Debugging
+    browser, err := pw.Chromium.Launch(playwright.BrowserTypeLaunchOptions{
+        Headless: playwright.Bool(false), 
+        SlowMo:   playwright.Float(100), // Slow actions by 100ms for visibility
+    })
+    if err != nil {
+        logger.Fatal("could not launch browser", zap.Error(err))
+    }
+    defer browser.Close() // Graceful cleanup
+
+    // 4. Create Isolated Context (Session)
+    context, err := browser.NewContext(playwright.BrowserNewContextOptions{
+        UserAgent: playwright.String("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)..."),
+        Viewport: &playwright.Size{Width: 1920, Height: 1080},
+    })
+    if err != nil {
+        logger.Fatal("could not create context", zap.Error(err))
+    }
+    defer context.Close()
+
+    // 5. Open Page
+    page, _ := context.NewPage()
+    
+    // ... Implementation ...
+}
+```
+
+### Human-Like Typing & Interaction
+```go
+import (
+    "math/rand"
+    "time"
+)
+
+// HumanType simulates a user typing with variable speed
+func HumanType(locator playwright.Locator, text string) {
+    // Focus the element first (like a human)
+    locator.Click()
+    
+    for _, char := range text {
+        // Random delay: 50ms to 150ms
+        delay := time.Duration(rand.Intn(100) + 50) * time.Millisecond
+        time.Sleep(delay)
+        locator.Press(string(char))
+    }
+}
+
+// HumanClick adds offset and hesitation
+func HumanClick(page playwright.Page, selector string) {
+    box, _ := page.Locator(selector).BoundingBox()
+    if box == nil {
+        return
+    }
+    
+    // Calculate center with random offset (jitter)
+    x := box.X + box.Width/2 + (rand.Float64()*10 - 5)
+    y := box.Y + box.Height/2 + (rand.Float64()*10 - 5)
+    
+    // Move mouse smoothly (requires custom Bezier implementation or steps)
+    page.Mouse().Move(x, y, playwright.MouseMoveOptions{Steps: playwright.Int(10)})
+    time.Sleep(100 * time.Millisecond) // Hesitate
+    page.Mouse().Click(x, y)
+}
+```
+
+#Session Management (Save/Load Cookies)
+
+```go
+func SaveSession(context playwright.BrowserContext, filepath string) {
+    cookies, _ := context.Cookies()
+    // Serialize cookies to JSON and write to 'filepath'
+}
+
+func LoadSession(context playwright.BrowserContext, filepath string) {
+    // Read JSON from 'filepath' and deserialize
+    // var cookies []playwright.Cookie
+    context.AddCookies(cookies)
+}
+```
+
+### Summary Checklist for Agent
+ - Is Debug Mode on? -> Headless=false, SlowMo=100+.
+ - Is it a new user identity? -> Create NewContext, apply new Proxy, rotate User-Agent.
+ - Is the action critical? -> Wrap in SafeAction with zap logging.
+ - Is the target guarded (Cloudflare/Akamai)? -> Enable HumanType, BezierMouse, and Stealth Scripts.