feat(commands): /update-skills syncs forks with upstream via 3-way merge

Upstream releases fixes worth pulling into the forks (arch-decide, playwright-js, playwright-py) without losing our local modifications. Each fork now has a manifest at upstreams/<name>/ plus a committed baseline snapshot that is the 3-way merge base. scripts/update-skills.py classifies each file's drift and merges to stdout. The command owns per-file confirmation, per-hunk conflict prompts, and every target write.

I centralized manifests under upstreams/ instead of per-skill dotfile dirs because arch-decide is now two flat files in commands/ and can't carry one. A "files" map in its manifest handles the upstream rename of SKILL.md to arch-decide.md.

I seeded baselines from today's upstream HEADs, so pre-existing local modifications classify as local-only from here on. git merge-file signals hard errors as exit 255, which subprocess reports as positive. The guard treats anything 128 and up as an error so a binary-file failure isn't misread as a conflict.

7 files changed, 521 insertions, 0 deletions

diff --git a/upstreams/playwright-py/baseline/LICENSE.txt b/upstreams/playwright-py/baseline/LICENSE.txt
new file mode 100644
index 0000000..4f881c5
--- /dev/null
+++ b/upstreams/playwright-py/baseline/LICENSE.txt
@@ -0,0 +1,202 @@
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diff --git a/upstreams/playwright-py/baseline/SKILL.md b/upstreams/playwright-py/baseline/SKILL.md
new file mode 100644
index 0000000..4726215
--- /dev/null
+++ b/upstreams/playwright-py/baseline/SKILL.md
@@ -0,0 +1,96 @@
+---
+name: webapp-testing
+description: Toolkit for interacting with and testing local web applications using Playwright. Supports verifying frontend functionality, debugging UI behavior, capturing browser screenshots, and viewing browser logs.
+license: Complete terms in LICENSE.txt
+---
+
+# Web Application Testing
+
+To test local web applications, write native Python Playwright scripts.
+
+**Helper Scripts Available**:
+- `scripts/with_server.py` - Manages server lifecycle (supports multiple servers)
+
+**Always run scripts with `--help` first** to see usage. DO NOT read the source until you try running the script first and find that a customized solution is abslutely necessary. These scripts can be very large and thus pollute your context window. They exist to be called directly as black-box scripts rather than ingested into your context window.
+
+## Decision Tree: Choosing Your Approach
+
+```
+User task → Is it static HTML?
+    ├─ Yes → Read HTML file directly to identify selectors
+    │         ├─ Success → Write Playwright script using selectors
+    │         └─ Fails/Incomplete → Treat as dynamic (below)
+    │
+    └─ No (dynamic webapp) → Is the server already running?
+        ├─ No → Run: python scripts/with_server.py --help
+        │        Then use the helper + write simplified Playwright script
+        │
+        └─ Yes → Reconnaissance-then-action:
+            1. Navigate and wait for networkidle
+            2. Take screenshot or inspect DOM
+            3. Identify selectors from rendered state
+            4. Execute actions with discovered selectors
+```
+
+## Example: Using with_server.py
+
+To start a server, run `--help` first, then use the helper:
+
+**Single server:**
+```bash
+python scripts/with_server.py --server "npm run dev" --port 5173 -- python your_automation.py
+```
+
+**Multiple servers (e.g., backend + frontend):**
+```bash
+python scripts/with_server.py \
+  --server "cd backend && python server.py" --port 3000 \
+  --server "cd frontend && npm run dev" --port 5173 \
+  -- python your_automation.py
+```
+
+To create an automation script, include only Playwright logic (servers are managed automatically):
+```python
+from playwright.sync_api import sync_playwright
+
+with sync_playwright() as p:
+    browser = p.chromium.launch(headless=True) # Always launch chromium in headless mode
+    page = browser.new_page()
+    page.goto('http://localhost:5173') # Server already running and ready
+    page.wait_for_load_state('networkidle') # CRITICAL: Wait for JS to execute
+    # ... your automation logic
+    browser.close()
+```
+
+## Reconnaissance-Then-Action Pattern
+
+1. **Inspect rendered DOM**:
+   ```python
+   page.screenshot(path='/tmp/inspect.png', full_page=True)
+   content = page.content()
+   page.locator('button').all()
+   ```
+
+2. **Identify selectors** from inspection results
+
+3. **Execute actions** using discovered selectors
+
+## Common Pitfall
+
+❌ **Don't** inspect the DOM before waiting for `networkidle` on dynamic apps
+✅ **Do** wait for `page.wait_for_load_state('networkidle')` before inspection
+
+## Best Practices
+
+- **Use bundled scripts as black boxes** - To accomplish a task, consider whether one of the scripts available in `scripts/` can help. These scripts handle common, complex workflows reliably without cluttering the context window. Use `--help` to see usage, then invoke directly. 
+- Use `sync_playwright()` for synchronous scripts
+- Always close the browser when done
+- Use descriptive selectors: `text=`, `role=`, CSS selectors, or IDs
+- Add appropriate waits: `page.wait_for_selector()` or `page.wait_for_timeout()`
+
+## Reference Files
+
+- **examples/** - Examples showing common patterns:
+  - `element_discovery.py` - Discovering buttons, links, and inputs on a page
+  - `static_html_automation.py` - Using file:// URLs for local HTML
+  - `console_logging.py` - Capturing console logs during automation
\ No newline at end of file
diff --git a/upstreams/playwright-py/baseline/examples/console_logging.py b/upstreams/playwright-py/baseline/examples/console_logging.py
new file mode 100644
index 0000000..9329b5e
--- /dev/null
+++ b/upstreams/playwright-py/baseline/examples/console_logging.py
@@ -0,0 +1,35 @@
+from playwright.sync_api import sync_playwright
+
+# Example: Capturing console logs during browser automation
+
+url = 'http://localhost:5173'  # Replace with your URL
+
+console_logs = []
+
+with sync_playwright() as p:
+    browser = p.chromium.launch(headless=True)
+    page = browser.new_page(viewport={'width': 1920, 'height': 1080})
+
+    # Set up console log capture
+    def handle_console_message(msg):
+        console_logs.append(f"[{msg.type}] {msg.text}")
+        print(f"Console: [{msg.type}] {msg.text}")
+
+    page.on("console", handle_console_message)
+
+    # Navigate to page
+    page.goto(url)
+    page.wait_for_load_state('networkidle')
+
+    # Interact with the page (triggers console logs)
+    page.click('text=Dashboard')
+    page.wait_for_timeout(1000)
+
+    browser.close()
+
+# Save console logs to file
+with open('/mnt/user-data/outputs/console.log', 'w') as f:
+    f.write('\n'.join(console_logs))
+
+print(f"\nCaptured {len(console_logs)} console messages")
+print(f"Logs saved to: /mnt/user-data/outputs/console.log")
\ No newline at end of file
diff --git a/upstreams/playwright-py/baseline/examples/element_discovery.py b/upstreams/playwright-py/baseline/examples/element_discovery.py
new file mode 100644
index 0000000..917ba72
--- /dev/null
+++ b/upstreams/playwright-py/baseline/examples/element_discovery.py
@@ -0,0 +1,40 @@
+from playwright.sync_api import sync_playwright
+
+# Example: Discovering buttons and other elements on a page
+
+with sync_playwright() as p:
+    browser = p.chromium.launch(headless=True)
+    page = browser.new_page()
+
+    # Navigate to page and wait for it to fully load
+    page.goto('http://localhost:5173')
+    page.wait_for_load_state('networkidle')
+
+    # Discover all buttons on the page
+    buttons = page.locator('button').all()
+    print(f"Found {len(buttons)} buttons:")
+    for i, button in enumerate(buttons):
+        text = button.inner_text() if button.is_visible() else "[hidden]"
+        print(f"  [{i}] {text}")
+
+    # Discover links
+    links = page.locator('a[href]').all()
+    print(f"\nFound {len(links)} links:")
+    for link in links[:5]:  # Show first 5
+        text = link.inner_text().strip()
+        href = link.get_attribute('href')
+        print(f"  - {text} -> {href}")
+
+    # Discover input fields
+    inputs = page.locator('input, textarea, select').all()
+    print(f"\nFound {len(inputs)} input fields:")
+    for input_elem in inputs:
+        name = input_elem.get_attribute('name') or input_elem.get_attribute('id') or "[unnamed]"
+        input_type = input_elem.get_attribute('type') or 'text'
+        print(f"  - {name} ({input_type})")
+
+    # Take screenshot for visual reference
+    page.screenshot(path='/tmp/page_discovery.png', full_page=True)
+    print("\nScreenshot saved to /tmp/page_discovery.png")
+
+    browser.close()
\ No newline at end of file
diff --git a/upstreams/playwright-py/baseline/examples/static_html_automation.py b/upstreams/playwright-py/baseline/examples/static_html_automation.py
new file mode 100644
index 0000000..90bbedc
--- /dev/null
+++ b/upstreams/playwright-py/baseline/examples/static_html_automation.py
@@ -0,0 +1,33 @@
+from playwright.sync_api import sync_playwright
+import os
+
+# Example: Automating interaction with static HTML files using file:// URLs
+
+html_file_path = os.path.abspath('path/to/your/file.html')
+file_url = f'file://{html_file_path}'
+
+with sync_playwright() as p:
+    browser = p.chromium.launch(headless=True)
+    page = browser.new_page(viewport={'width': 1920, 'height': 1080})
+
+    # Navigate to local HTML file
+    page.goto(file_url)
+
+    # Take screenshot
+    page.screenshot(path='/mnt/user-data/outputs/static_page.png', full_page=True)
+
+    # Interact with elements
+    page.click('text=Click Me')
+    page.fill('#name', 'John Doe')
+    page.fill('#email', 'john@example.com')
+
+    # Submit form
+    page.click('button[type="submit"]')
+    page.wait_for_timeout(500)
+
+    # Take final screenshot
+    page.screenshot(path='/mnt/user-data/outputs/after_submit.png', full_page=True)
+
+    browser.close()
+
+print("Static HTML automation completed!")
\ No newline at end of file
diff --git a/upstreams/playwright-py/baseline/scripts/with_server.py b/upstreams/playwright-py/baseline/scripts/with_server.py
new file mode 100755
index 0000000..431f2eb
--- /dev/null
+++ b/upstreams/playwright-py/baseline/scripts/with_server.py
@@ -0,0 +1,106 @@
+#!/usr/bin/env python3
+"""
+Start one or more servers, wait for them to be ready, run a command, then clean up.
+
+Usage:
+    # Single server
+    python scripts/with_server.py --server "npm run dev" --port 5173 -- python automation.py
+    python scripts/with_server.py --server "npm start" --port 3000 -- python test.py
+
+    # Multiple servers
+    python scripts/with_server.py \
+      --server "cd backend && python server.py" --port 3000 \
+      --server "cd frontend && npm run dev" --port 5173 \
+      -- python test.py
+"""
+
+import subprocess
+import socket
+import time
+import sys
+import argparse
+
+def is_server_ready(port, timeout=30):
+    """Wait for server to be ready by polling the port."""
+    start_time = time.time()
+    while time.time() - start_time < timeout:
+        try:
+            with socket.create_connection(('localhost', port), timeout=1):
+                return True
+        except (socket.error, ConnectionRefusedError):
+            time.sleep(0.5)
+    return False
+
+
+def main():
+    parser = argparse.ArgumentParser(description='Run command with one or more servers')
+    parser.add_argument('--server', action='append', dest='servers', required=True, help='Server command (can be repeated)')
+    parser.add_argument('--port', action='append', dest='ports', type=int, required=True, help='Port for each server (must match --server count)')
+    parser.add_argument('--timeout', type=int, default=30, help='Timeout in seconds per server (default: 30)')
+    parser.add_argument('command', nargs=argparse.REMAINDER, help='Command to run after server(s) ready')
+
+    args = parser.parse_args()
+
+    # Remove the '--' separator if present
+    if args.command and args.command[0] == '--':
+        args.command = args.command[1:]
+
+    if not args.command:
+        print("Error: No command specified to run")
+        sys.exit(1)
+
+    # Parse server configurations
+    if len(args.servers) != len(args.ports):
+        print("Error: Number of --server and --port arguments must match")
+        sys.exit(1)
+
+    servers = []
+    for cmd, port in zip(args.servers, args.ports):
+        servers.append({'cmd': cmd, 'port': port})
+
+    server_processes = []
+
+    try:
+        # Start all servers
+        for i, server in enumerate(servers):
+            print(f"Starting server {i+1}/{len(servers)}: {server['cmd']}")
+
+            # Use shell=True to support commands with cd and &&
+            process = subprocess.Popen(
+                server['cmd'],
+                shell=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE
+            )
+            server_processes.append(process)
+
+            # Wait for this server to be ready
+            print(f"Waiting for server on port {server['port']}...")
+            if not is_server_ready(server['port'], timeout=args.timeout):
+                raise RuntimeError(f"Server failed to start on port {server['port']} within {args.timeout}s")
+
+            print(f"Server ready on port {server['port']}")
+
+        print(f"\nAll {len(servers)} server(s) ready")
+
+        # Run the command
+        print(f"Running: {' '.join(args.command)}\n")
+        result = subprocess.run(args.command)
+        sys.exit(result.returncode)
+
+    finally:
+        # Clean up all servers
+        print(f"\nStopping {len(server_processes)} server(s)...")
+        for i, process in enumerate(server_processes):
+            try:
+                process.terminate()
+                process.wait(timeout=5)
+            except subprocess.TimeoutExpired:
+                process.kill()
+                process.wait()
+            print(f"Server {i+1} stopped")
+        print("All servers stopped")
+
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file
diff --git a/upstreams/playwright-py/manifest.json b/upstreams/playwright-py/manifest.json
new file mode 100644
index 0000000..4b1f98d
--- /dev/null
+++ b/upstreams/playwright-py/manifest.json
@@ -0,0 +1,9 @@
+{
+  "name": "playwright-py",
+  "url": "https://github.com/anthropics/skills",
+  "ref": "main",
+  "subpath": "skills/webapp-testing",
+  "target": "playwright-py",
+  "license": "Apache-2.0",
+  "last_synced_commit": "57546260929473d4e0d1c1bb75297be2fdfa1949"
+}