diff --git a/.github/hooks/impeccable.json b/.github/hooks/impeccable.json
index 0e9378094..a909ad43b 100644
--- a/.github/hooks/impeccable.json
+++ b/.github/hooks/impeccable.json
@@ -5,7 +5,7 @@
       {
         "type": "command",
         "matcher": "edit|create|apply_patch",
-        "bash": "node \"$(git rev-parse --show-toplevel)/.github/skills/impeccable/scripts/hook.mjs\"",
+        "bash": "[ ! -f \"$(git rev-parse --show-toplevel)/.github/skills/impeccable/scripts/hook.mjs\" ] || ! node -e \"import('fs')\" 2>/dev/null || node \"$(git rev-parse --show-toplevel)/.github/skills/impeccable/scripts/hook.mjs\"",
         "timeoutSec": 5
       }
     ]
diff --git a/.grok/hooks/impeccable.json b/.grok/hooks/impeccable.json
index 7d007a6fa..48b80bf30 100644
--- a/.grok/hooks/impeccable.json
+++ b/.grok/hooks/impeccable.json
@@ -6,7 +6,7 @@
         "hooks": [
           {
             "type": "command",
-            "command": "node \".grok/skills/impeccable/scripts/hook.mjs\"",
+            "command": "[ ! -f \".grok/skills/impeccable/scripts/hook.mjs\" ] || ! node -e \"import('fs')\" 2>/dev/null || node \".grok/skills/impeccable/scripts/hook.mjs\"",
             "timeout": 5,
             "statusMessage": "Checking UI changes"
           }
@@ -18,7 +18,7 @@
         "hooks": [
           {
             "type": "command",
-            "command": "node \".grok/skills/impeccable/scripts/hook.mjs\"",
+            "command": "[ ! -f \".grok/skills/impeccable/scripts/hook.mjs\" ] || ! node -e \"import('fs')\" 2>/dev/null || node \".grok/skills/impeccable/scripts/hook.mjs\"",
             "timeout": 30,
             "statusMessage": "Design deep pass"
           }
diff --git a/scripts/lib/transformers/hooks.js b/scripts/lib/transformers/hooks.js
index e92ae29d8..443ab2ef3 100644
--- a/scripts/lib/transformers/hooks.js
+++ b/scripts/lib/transformers/hooks.js
@@ -60,10 +60,12 @@ const CLAUDE_PROJECT_HOOK = '${CLAUDE_PROJECT_DIR}/.claude/skills/impeccable/scr
 //
 // `notice` is the shell that reports the dead runtime to the user, and it is
 // passed in rather than baked in because the wire format is per harness. Claude
-// Code reads a `systemMessage` field off stdout on exit 0; what Codex and Cursor
-// do with stdout they did not ask for is unconfirmed, so they take the probe
-// alone and an unsupported runtime stays as quiet there as it was before the
-// probe existed. Adding their shape later is one more argument at the call site.
+// Code reads a `systemMessage` field off stdout on exit 0. Codex expects
+// `hookSpecificOutput` and Cursor a permission-shaped payload, so handing either
+// a Claude response gets it discarded or printed raw; until those shapes are
+// confirmed every non-Claude harness takes the probe alone, and an unsupported
+// runtime stays as quiet there as it was before the probe existed. Adding a
+// shape later is one more argument at that harness's call site.
 const guardedNode = (hookPath, notice = '') => {
   const probe = notice
     ? `! { node -e "import('fs')" 2>/dev/null || { ${notice}; exit 0; }; }`
@@ -156,14 +158,14 @@ export function buildCodexPluginHooksManifest() {
           hooks: [
             {
               type: 'command',
-              command: `node "${CODEX_PLUGIN_HOOK}"`,
+              command: guardedNode(CODEX_PLUGIN_HOOK),
               timeout: TIMEOUT_SECONDS,
               statusMessage: STATUS_MESSAGE,
             },
           ],
         },
       ],
-      Stop: [stopEntry(`node "${CODEX_PLUGIN_HOOK}"`)],
+      Stop: [stopEntry(guardedNode(CODEX_PLUGIN_HOOK))],
     },
   };
 }
@@ -226,7 +228,7 @@ export function buildGitHubHooksManifest() {
         {
           type: 'command',
           matcher: 'edit|create|apply_patch',
-          bash: `node "${GITHUB_PROJECT_HOOK}"`,
+          bash: guardedNode(GITHUB_PROJECT_HOOK),
           timeoutSec: TIMEOUT_SECONDS,
         },
       ],
@@ -248,14 +250,14 @@ export function buildGrokHooksManifest() {
           hooks: [
             {
               type: 'command',
-              command: `node "${GROK_PROJECT_HOOK}"`,
+              command: guardedNode(GROK_PROJECT_HOOK),
               timeout: TIMEOUT_SECONDS,
               statusMessage: STATUS_MESSAGE,
             },
           ],
         },
       ],
-      Stop: [stopEntry(`node "${GROK_PROJECT_HOOK}"`)],
+      Stop: [stopEntry(guardedNode(GROK_PROJECT_HOOK))],
     },
   };
 }
diff --git a/tests/hook-build.test.mjs b/tests/hook-build.test.mjs
index 937610775..3e8754f32 100644
--- a/tests/hook-build.test.mjs
+++ b/tests/hook-build.test.mjs
@@ -28,8 +28,9 @@ function readJson(rel) {
 function expectCommand(command, expectedPath) {
   assert.equal(typeof command, 'string');
   // node-command providers carry the missing-file guard (issue #399: exits 0
-  // when absent, preserves node's exit code when present); github/grok keep
-  // their own portable unguarded forms.
+  // when absent, preserves node's exit code when present) plus the runtime probe
+  // (issue #410: exits 0 when node cannot load ESM). GitHub's portable
+  // `$(git rev-parse)` form is guarded too, so it lands in the same branch.
   if (command.startsWith('[ ! -f "')) {
     assert.match(command, /\|\| node "/);
   } else {