refactor: extract command registry to commands.ts, add SNAPSHOT_FLAGS metadata

- NEW: browse/src/commands.ts — command sets + COMMAND_DESCRIPTIONS + load-time validation (zero side effects)
- server.ts imports from commands.ts instead of declaring sets inline
- snapshot.ts: SNAPSHOT_FLAGS array drives parseSnapshotArgs (metadata-driven, no duplication)
- All 186 existing tests pass

browse/src/commands.ts

@@ -0,0 +1,107 @@
+/**
+ * Command registry — single source of truth for all browse commands.
+ *
+ * Dependency graph:
+ *   commands.ts ──▶ server.ts (runtime dispatch)
+ *                ──▶ gen-skill-docs.ts (doc generation)
+ *                ──▶ skill-parser.ts (validation)
+ *                ──▶ skill-check.ts (health reporting)
+ *
+ * Zero side effects. Safe to import from build scripts and tests.
+ */
+
+export const READ_COMMANDS = new Set([
+  'text', 'html', 'links', 'forms', 'accessibility',
+  'js', 'eval', 'css', 'attrs',
+  'console', 'network', 'cookies', 'storage', 'perf',
+  'dialog', 'is',
+]);
+
+export const WRITE_COMMANDS = new Set([
+  'goto', 'back', 'forward', 'reload',
+  'click', 'fill', 'select', 'hover', 'type', 'press', 'scroll', 'wait',
+  'viewport', 'cookie', 'cookie-import', 'cookie-import-browser', 'header', 'useragent',
+  'upload', 'dialog-accept', 'dialog-dismiss',
+]);
+
+export const META_COMMANDS = new Set([
+  'tabs', 'tab', 'newtab', 'closetab',
+  'status', 'stop', 'restart',
+  'screenshot', 'pdf', 'responsive',
+  'chain', 'diff',
+  'url', 'snapshot',
+]);
+
+export const ALL_COMMANDS = new Set([...READ_COMMANDS, ...WRITE_COMMANDS, ...META_COMMANDS]);
+
+export const COMMAND_DESCRIPTIONS: Record<string, { category: string; description: string; usage?: string }> = {
+  // Navigation
+  'goto':    { category: 'Navigation', description: 'Navigate to URL', usage: 'goto <url>' },
+  'back':    { category: 'Navigation', description: 'History back' },
+  'forward': { category: 'Navigation', description: 'History forward' },
+  'reload':  { category: 'Navigation', description: 'Reload page' },
+  'url':     { category: 'Navigation', description: 'Print current URL' },
+  // Reading
+  'text':    { category: 'Reading', description: 'Cleaned page text' },
+  'html':    { category: 'Reading', description: 'innerHTML', usage: 'html [selector]' },
+  'links':   { category: 'Reading', description: 'All links as "text → href"' },
+  'forms':   { category: 'Reading', description: 'Form fields as JSON' },
+  'accessibility': { category: 'Reading', description: 'Full ARIA tree' },
+  // Inspection
+  'js':      { category: 'Inspection', description: 'Run JavaScript', usage: 'js <expr>' },
+  'eval':    { category: 'Inspection', description: 'Run JS file', usage: 'eval <file>' },
+  'css':     { category: 'Inspection', description: 'Computed CSS value', usage: 'css <sel> <prop>' },
+  'attrs':   { category: 'Inspection', description: 'Element attributes as JSON', usage: 'attrs <sel>' },
+  'is':      { category: 'Inspection', description: 'State check', usage: 'is <prop> <sel>' },
+  'console': { category: 'Inspection', description: 'Console messages', usage: 'console [--clear|--errors]' },
+  'network': { category: 'Inspection', description: 'Network requests', usage: 'network [--clear]' },
+  'dialog':  { category: 'Inspection', description: 'Dialog messages', usage: 'dialog [--clear]' },
+  'cookies': { category: 'Inspection', description: 'All cookies as JSON' },
+  'storage': { category: 'Inspection', description: 'localStorage + sessionStorage', usage: 'storage [set k v]' },
+  'perf':    { category: 'Inspection', description: 'Page load timings' },
+  // Interaction
+  'click':   { category: 'Interaction', description: 'Click element', usage: 'click <sel>' },
+  'fill':    { category: 'Interaction', description: 'Fill input', usage: 'fill <sel> <val>' },
+  'select':  { category: 'Interaction', description: 'Select dropdown option', usage: 'select <sel> <val>' },
+  'hover':   { category: 'Interaction', description: 'Hover element', usage: 'hover <sel>' },
+  'type':    { category: 'Interaction', description: 'Type into focused element', usage: 'type <text>' },
+  'press':   { category: 'Interaction', description: 'Press key', usage: 'press <key>' },
+  'scroll':  { category: 'Interaction', description: 'Scroll element into view', usage: 'scroll [sel]' },
+  'wait':    { category: 'Interaction', description: 'Wait for element/condition', usage: 'wait <sel|--networkidle|--load>' },
+  'upload':  { category: 'Interaction', description: 'Upload file(s)', usage: 'upload <sel> <file...>' },
+  'viewport':{ category: 'Interaction', description: 'Set viewport size', usage: 'viewport <WxH>' },
+  'cookie':  { category: 'Interaction', description: 'Set cookie' },
+  'cookie-import': { category: 'Interaction', description: 'Import cookies from JSON file', usage: 'cookie-import <json>' },
+  'cookie-import-browser': { category: 'Interaction', description: 'Import cookies from real browser', usage: 'cookie-import-browser [browser] [--domain d]' },
+  'header':  { category: 'Interaction', description: 'Set custom request header', usage: 'header <name> <value>' },
+  'useragent': { category: 'Interaction', description: 'Set user agent', usage: 'useragent <string>' },
+  'dialog-accept': { category: 'Interaction', description: 'Auto-accept next dialog', usage: 'dialog-accept [text]' },
+  'dialog-dismiss': { category: 'Interaction', description: 'Auto-dismiss next dialog' },
+  // Visual
+  'screenshot': { category: 'Visual', description: 'Save screenshot', usage: 'screenshot [path]' },
+  'pdf':     { category: 'Visual', description: 'Save as PDF', usage: 'pdf [path]' },
+  'responsive': { category: 'Visual', description: 'Mobile/tablet/desktop screenshots', usage: 'responsive [prefix]' },
+  'diff':    { category: 'Visual', description: 'Text diff between pages', usage: 'diff <url1> <url2>' },
+  // Tabs
+  'tabs':    { category: 'Tabs', description: 'List open tabs' },
+  'tab':     { category: 'Tabs', description: 'Switch to tab', usage: 'tab <id>' },
+  'newtab':  { category: 'Tabs', description: 'Open new tab', usage: 'newtab [url]' },
+  'closetab':{ category: 'Tabs', description: 'Close tab', usage: 'closetab [id]' },
+  // Server
+  'status':  { category: 'Server', description: 'Health check' },
+  'stop':    { category: 'Server', description: 'Shutdown server' },
+  'restart': { category: 'Server', description: 'Restart server' },
+  // Meta
+  'snapshot':{ category: 'Snapshot', description: 'Accessibility tree with @refs', usage: 'snapshot [flags]' },
+  'chain':   { category: 'Meta', description: 'Multi-command from JSON stdin' },
+};
+
+// Load-time validation: descriptions must cover exactly the command sets
+const allCmds = new Set([...READ_COMMANDS, ...WRITE_COMMANDS, ...META_COMMANDS]);
+const descKeys = new Set(Object.keys(COMMAND_DESCRIPTIONS));
+for (const cmd of allCmds) {
+  if (!descKeys.has(cmd)) throw new Error(`COMMAND_DESCRIPTIONS missing entry for: ${cmd}`);
+}
+for (const key of descKeys) {
+  if (!allCmds.has(key)) throw new Error(`COMMAND_DESCRIPTIONS has unknown command: ${key}`);
+}

browse/src/server.ts

@@ -110,28 +110,9 @@ const idleCheckInterval = setInterval(() => {
   }
 }, 60_000);
 
-// ─── Command Sets (exported for chain command) ──────────────────
+// ─── Command Sets (from commands.ts — single source of truth) ───
-export const READ_COMMANDS = new Set([
+import { READ_COMMANDS, WRITE_COMMANDS, META_COMMANDS } from './commands';
-  'text', 'html', 'links', 'forms', 'accessibility',
+export { READ_COMMANDS, WRITE_COMMANDS, META_COMMANDS };
-  'js', 'eval', 'css', 'attrs',
-  'console', 'network', 'cookies', 'storage', 'perf',
-  'dialog', 'is',
-]);
-
-export const WRITE_COMMANDS = new Set([
-  'goto', 'back', 'forward', 'reload',
-  'click', 'fill', 'select', 'hover', 'type', 'press', 'scroll', 'wait',
-  'viewport', 'cookie', 'cookie-import', 'cookie-import-browser', 'header', 'useragent',
-  'upload', 'dialog-accept', 'dialog-dismiss',
-]);
-
-export const META_COMMANDS = new Set([
-  'tabs', 'tab', 'newtab', 'closetab',
-  'status', 'stop', 'restart',
-  'screenshot', 'pdf', 'responsive',
-  'chain', 'diff',
-  'url', 'snapshot',
-]);
 
 // ─── Server ────────────────────────────────────────────────────
 const browserManager = new BrowserManager();

browse/src/snapshot.ts

@@ -40,6 +40,30 @@ interface SnapshotOptions {
   cursorInteractive?: boolean; // -C / --cursor-interactive: scan cursor:pointer etc.
 }
 
+/**
+ * Snapshot flag metadata — single source of truth for CLI parsing and doc generation.
+ *
+ * Imported by:
+ *   - gen-skill-docs.ts (generates {{SNAPSHOT_FLAGS}} tables)
+ *   - skill-parser.ts (validates flags in SKILL.md examples)
+ */
+export const SNAPSHOT_FLAGS: Array<{
+  short: string;
+  long: string;
+  description: string;
+  takesValue?: boolean;
+  optionKey: keyof SnapshotOptions;
+}> = [
+  { short: '-i', long: '--interactive', description: 'Interactive elements only', optionKey: 'interactive' },
+  { short: '-c', long: '--compact', description: 'Remove empty structural elements', optionKey: 'compact' },
+  { short: '-d', long: '--depth', description: 'Limit tree depth', takesValue: true, optionKey: 'depth' },
+  { short: '-s', long: '--selector', description: 'Scope to CSS selector', takesValue: true, optionKey: 'selector' },
+  { short: '-D', long: '--diff', description: 'Diff against previous snapshot', optionKey: 'diff' },
+  { short: '-a', long: '--annotate', description: 'Annotated screenshot with ref labels', optionKey: 'annotate' },
+  { short: '-o', long: '--output', description: 'Output path for annotated screenshot', takesValue: true, optionKey: 'outputPath' },
+  { short: '-C', long: '--cursor-interactive', description: 'Scan cursor:pointer/onclick/tabindex elements', optionKey: 'cursorInteractive' },
+];
+
 interface ParsedNode {
   indent: number;
   role: string;
@@ -50,49 +74,24 @@ interface ParsedNode {
 }
 
 /**
- * Parse CLI args into SnapshotOptions
+ * Parse CLI args into SnapshotOptions — driven by SNAPSHOT_FLAGS metadata.
  */
 export function parseSnapshotArgs(args: string[]): SnapshotOptions {
   const opts: SnapshotOptions = {};
   for (let i = 0; i < args.length; i++) {
-    switch (args[i]) {
+    const flag = SNAPSHOT_FLAGS.find(f => f.short === args[i] || f.long === args[i]);
-      case '-i':
+    if (!flag) throw new Error(`Unknown snapshot flag: ${args[i]}`);
-      case '--interactive':
+    if (flag.takesValue) {
-        opts.interactive = true;
+      const value = args[++i];
-        break;
+      if (!value) throw new Error(`Usage: snapshot ${flag.short} <value>`);
-      case '-c':
+      if (flag.optionKey === 'depth') {
-      case '--compact':
+        (opts as any)[flag.optionKey] = parseInt(value, 10);
-        opts.compact = true;
-        break;
-      case '-d':
-      case '--depth':
-        opts.depth = parseInt(args[++i], 10);
         if (isNaN(opts.depth!)) throw new Error('Usage: snapshot -d <number>');
-        break;
+      } else {
-      case '-s':
+        (opts as any)[flag.optionKey] = value;
-      case '--selector':
+      }
-        opts.selector = args[++i];
+    } else {
-        if (!opts.selector) throw new Error('Usage: snapshot -s <selector>');
+      (opts as any)[flag.optionKey] = true;
-        break;
-      case '-D':
-      case '--diff':
-        opts.diff = true;
-        break;
-      case '-a':
-      case '--annotate':
-        opts.annotate = true;
-        break;
-      case '-o':
-      case '--output':
-        opts.outputPath = args[++i];
-        if (!opts.outputPath) throw new Error('Usage: snapshot -o <path>');
-        break;
-      case '-C':
-      case '--cursor-interactive':
-        opts.cursorInteractive = true;
-        break;
-      default:
-        throw new Error(`Unknown snapshot flag: ${args[i]}`);
     }
   }
   return opts;