diff --git a/commands/auto-update.md b/commands/auto-update.md
index b1f39d17d..d685bd24a 100644
--- a/commands/auto-update.md
+++ b/commands/auto-update.md
@@ -11,7 +11,7 @@ Update ECC from its upstream repo and regenerate the current context's managed i
 
 ```bash
 # Preview the update without mutating anything
-ECC_ROOT="${CLAUDE_PLUGIN_ROOT:-$(node -e "var r=(function(){var p=require('path'),f=require('fs'),o=require('os');var e=process.env.CLAUDE_PLUGIN_ROOT;if(e&&e.trim())return e.trim();var d=p.join(o.homedir(),'.claude');function L(x){try{return require(p.join(x,'scripts','lib','resolve-ecc-root')).resolveEccRoot()}catch(_){return null}}var r=L(d);if(r)return r;var s=['ecc','ecc@ecc','marketplaces/ecc','everything-claude-code','everything-claude-code@everything-claude-code','marketplaces/everything-claude-code'];for(var i=0;i<s.length;i++){r=L(p.join(d,'plugins',s[i]));if(r)return r}try{var g=['ecc','everything-claude-code'];for(var j=0;j<g.length;j++){var c=p.join(d,'plugins','cache',g[j]);var O=f.readdirSync(c);for(var k=0;k<O.length;k++){var q=p.join(c,O[k]);var V=f.readdirSync(q);for(var m=0;m<V.length;m++){r=L(p.join(q,V[m]));if(r)return r}}}}catch(_){}return d})();console.log(r)")}"
+ECC_ROOT="${CLAUDE_PLUGIN_ROOT:-$(node -e "var r=(function(){var p=require('path'),f=require('fs'),o=require('os');var e=process.env.CLAUDE_PLUGIN_ROOT;if(e&&e.trim())return e.trim();var d=p.join(o.homedir(),'.claude');function L(x){try{return require(p.join(x,'scripts','lib','resolve-ecc-root')).resolveEccRoot({probe:p.join('scripts','auto-update.js')})}catch(_){return null}}var r=L(d);if(r)return r;var s=['ecc','ecc@ecc','marketplaces/ecc','everything-claude-code','everything-claude-code@everything-claude-code','marketplaces/everything-claude-code'];for(var i=0;i<s.length;i++){r=L(p.join(d,'plugins',s[i]));if(r)return r}try{var g=['ecc','everything-claude-code'];for(var j=0;j<g.length;j++){var c=p.join(d,'plugins','cache',g[j]);var O=f.readdirSync(c);for(var k=0;k<O.length;k++){var q=p.join(c,O[k]);var V=f.readdirSync(q);for(var m=0;m<V.length;m++){r=L(p.join(q,V[m]));if(r)return r}}}}catch(_){}return d})();console.log(r)")}"
 node "$ECC_ROOT/scripts/auto-update.js" --dry-run
 
 # Update only Cursor-managed files in the current project
diff --git a/docs/ja-JP/commands/auto-update.md b/docs/ja-JP/commands/auto-update.md
index 74e766346..b5147f502 100644
--- a/docs/ja-JP/commands/auto-update.md
+++ b/docs/ja-JP/commands/auto-update.md
@@ -11,7 +11,7 @@ ECCをアップストリームリポジトリから更新し、元のインス
 
 ```bash
 # 何も変更せずに更新をプレビュー
-ECC_ROOT="${CLAUDE_PLUGIN_ROOT:-$(node -e "var r=(function(){var p=require('path'),f=require('fs'),o=require('os');var e=process.env.CLAUDE_PLUGIN_ROOT;if(e&&e.trim())return e.trim();var d=p.join(o.homedir(),'.claude');function L(x){try{return require(p.join(x,'scripts','lib','resolve-ecc-root')).resolveEccRoot()}catch(_){return null}}var r=L(d);if(r)return r;var s=['ecc','ecc@ecc','marketplaces/ecc','everything-claude-code','everything-claude-code@everything-claude-code','marketplaces/everything-claude-code'];for(var i=0;i<s.length;i++){r=L(p.join(d,'plugins',s[i]));if(r)return r}try{var g=['ecc','everything-claude-code'];for(var j=0;j<g.length;j++){var c=p.join(d,'plugins','cache',g[j]);var O=f.readdirSync(c);for(var k=0;k<O.length;k++){var q=p.join(c,O[k]);var V=f.readdirSync(q);for(var m=0;m<V.length;m++){r=L(p.join(q,V[m]));if(r)return r}}}}catch(_){}return d})();console.log(r)")}"
+ECC_ROOT="${CLAUDE_PLUGIN_ROOT:-$(node -e "var r=(function(){var p=require('path'),f=require('fs'),o=require('os');var e=process.env.CLAUDE_PLUGIN_ROOT;if(e&&e.trim())return e.trim();var d=p.join(o.homedir(),'.claude');function L(x){try{return require(p.join(x,'scripts','lib','resolve-ecc-root')).resolveEccRoot({probe:p.join('scripts','auto-update.js')})}catch(_){return null}}var r=L(d);if(r)return r;var s=['ecc','ecc@ecc','marketplaces/ecc','everything-claude-code','everything-claude-code@everything-claude-code','marketplaces/everything-claude-code'];for(var i=0;i<s.length;i++){r=L(p.join(d,'plugins',s[i]));if(r)return r}try{var g=['ecc','everything-claude-code'];for(var j=0;j<g.length;j++){var c=p.join(d,'plugins','cache',g[j]);var O=f.readdirSync(c);for(var k=0;k<O.length;k++){var q=p.join(c,O[k]);var V=f.readdirSync(q);for(var m=0;m<V.length;m++){r=L(p.join(q,V[m]));if(r)return r}}}}catch(_){}return d})();console.log(r)")}"
 node "$ECC_ROOT/scripts/auto-update.js" --dry-run
 
 # 現在のプロジェクトのCursor管理ファイルのみ更新
diff --git a/docs/zh-CN/commands/auto-update.md b/docs/zh-CN/commands/auto-update.md
index fd4e018af..da68addfe 100644
--- a/docs/zh-CN/commands/auto-update.md
+++ b/docs/zh-CN/commands/auto-update.md
@@ -11,7 +11,7 @@ disable-model-invocation: true
 
 ```bash
 # Preview the update without mutating anything
-ECC_ROOT="${CLAUDE_PLUGIN_ROOT:-$(node -e "var r=(function(){var p=require('path'),f=require('fs'),o=require('os');var e=process.env.CLAUDE_PLUGIN_ROOT;if(e&&e.trim())return e.trim();var d=p.join(o.homedir(),'.claude');function L(x){try{return require(p.join(x,'scripts','lib','resolve-ecc-root')).resolveEccRoot()}catch(_){return null}}var r=L(d);if(r)return r;var s=['ecc','ecc@ecc','marketplaces/ecc','everything-claude-code','everything-claude-code@everything-claude-code','marketplaces/everything-claude-code'];for(var i=0;i<s.length;i++){r=L(p.join(d,'plugins',s[i]));if(r)return r}try{var g=['ecc','everything-claude-code'];for(var j=0;j<g.length;j++){var c=p.join(d,'plugins','cache',g[j]);var O=f.readdirSync(c);for(var k=0;k<O.length;k++){var q=p.join(c,O[k]);var V=f.readdirSync(q);for(var m=0;m<V.length;m++){r=L(p.join(q,V[m]));if(r)return r}}}}catch(_){}return d})();console.log(r)")}"
+ECC_ROOT="${CLAUDE_PLUGIN_ROOT:-$(node -e "var r=(function(){var p=require('path'),f=require('fs'),o=require('os');var e=process.env.CLAUDE_PLUGIN_ROOT;if(e&&e.trim())return e.trim();var d=p.join(o.homedir(),'.claude');function L(x){try{return require(p.join(x,'scripts','lib','resolve-ecc-root')).resolveEccRoot({probe:p.join('scripts','auto-update.js')})}catch(_){return null}}var r=L(d);if(r)return r;var s=['ecc','ecc@ecc','marketplaces/ecc','everything-claude-code','everything-claude-code@everything-claude-code','marketplaces/everything-claude-code'];for(var i=0;i<s.length;i++){r=L(p.join(d,'plugins',s[i]));if(r)return r}try{var g=['ecc','everything-claude-code'];for(var j=0;j<g.length;j++){var c=p.join(d,'plugins','cache',g[j]);var O=f.readdirSync(c);for(var k=0;k<O.length;k++){var q=p.join(c,O[k]);var V=f.readdirSync(q);for(var m=0;m<V.length;m++){r=L(p.join(q,V[m]));if(r)return r}}}}catch(_){}return d})();console.log(r)")}"
 node "$ECC_ROOT/scripts/auto-update.js" --dry-run
 
 # Update only Cursor-managed files in the current project
diff --git a/tests/lib/command-plugin-root.test.js b/tests/lib/command-plugin-root.test.js
index 9630d087d..287001fe9 100644
--- a/tests/lib/command-plugin-root.test.js
+++ b/tests/lib/command-plugin-root.test.js
@@ -50,6 +50,29 @@ test('instinct-status command uses shared inline resolver (no stale legacy fallb
   );
 });
 
+test('auto-update command probes for the script it runs, not just scripts/lib', () => {
+  // A partial install can carry full resolver evidence (script tree plus
+  // sentinel ECC skill, per #2544/#2577) yet still lack scripts/auto-update.js.
+  // The command's inline resolver must probe for the script it actually
+  // executes so such roots don't shadow the complete plugin root.
+  const autoUpdateDocs = [
+    path.join(__dirname, '..', '..', 'commands', 'auto-update.md'),
+    path.join(__dirname, '..', '..', 'docs', 'ja-JP', 'commands', 'auto-update.md'),
+    path.join(__dirname, '..', '..', 'docs', 'zh-CN', 'commands', 'auto-update.md'),
+  ];
+  for (const docPath of autoUpdateDocs) {
+    const doc = fs.readFileSync(docPath, 'utf8');
+    assert.strictEqual(
+      (doc.match(/scripts','lib','resolve-ecc-root/g) || []).length, 1,
+      `${docPath} should embed the shared inline resolver`
+    );
+    assert.ok(
+      doc.includes("resolveEccRoot({probe:p.join('scripts','auto-update.js')})"),
+      `${docPath} should probe for scripts/auto-update.js`
+    );
+  }
+});
+
 test('resolveEccRoot module covers current and legacy marketplace plugin roots', () => {
   const { resolveEccRoot } = require('../../scripts/lib/resolve-ecc-root');
   assert.ok(typeof resolveEccRoot === 'function');
diff --git a/tests/lib/resolve-ecc-root.test.js b/tests/lib/resolve-ecc-root.test.js
index 36a8c0c13..25a53773c 100644
--- a/tests/lib/resolve-ecc-root.test.js
+++ b/tests/lib/resolve-ecc-root.test.js
@@ -363,6 +363,37 @@ function runTests() {
     }
   })) passed++; else failed++;
 
+  if (test('custom probe skips a qualifying root that lacks the probed script (auto-update)', () => {
+    // The surviving failure shape after #2544/#2577: a partial install can
+    // carry full resolver evidence (script tree + sentinel ECC skill) yet
+    // still lack the top-level script that auto-update will execute. The
+    // default probe rightly accepts such a root; a caller probing for the
+    // script it runs must skip it and reach the complete plugin root.
+    const homeDir = createTempDir();
+    try {
+      const claudeDir = setupStandardInstall(homeDir);
+      const marketplaceRoot = setupLegacyPluginInstall(homeDir, ['marketplaces', 'ecc']);
+      fs.writeFileSync(path.join(marketplaceRoot, 'scripts', 'auto-update.js'), '// stub');
+
+      assert.strictEqual(
+        resolveEccRoot({ envRoot: '', homeDir }),
+        claudeDir,
+        'default probe accepts a root with full resolver evidence'
+      );
+      assert.strictEqual(
+        resolveEccRoot({
+          envRoot: '',
+          homeDir,
+          probe: path.join('scripts', 'auto-update.js'),
+        }),
+        marketplaceRoot,
+        'auto-update probe must skip roots that lack the script it will execute'
+      );
+    } finally {
+      fs.rmSync(homeDir, { recursive: true, force: true });
+    }
+  })) passed++; else failed++;
+
   // ─── INLINE_RESOLVE ───
 
   if (test('INLINE_RESOLVE is a non-empty string', () => {