diff --git a/scripts/lib/install/apply.js b/scripts/lib/install/apply.js
index fc263b3d0..27906161d 100644
--- a/scripts/lib/install/apply.js
+++ b/scripts/lib/install/apply.js
@@ -451,9 +451,16 @@ function activationIsInactive(kind, operation, content) {
     return content.toString('utf8') === getDisabledOpenCodePluginContent();
   }
   const text = content.toString('utf8');
+  const relativePath = operation.sourceRelativePath || operation.destinationPath;
   // JSONC-tolerant parse so a comment in the user's config does not crash
   // the install; the ownership guard never writes this file (issue #3546).
-  const config = parseJsoncConfig(text, operation.sourceRelativePath || operation.destinationPath);
+  const config = parseJsoncConfig(text, relativePath);
+  // Keep the same shape error the strict parser surfaced via
+  // disableOpenCodeHookPluginRegistration: a non-array plugin must not
+  // silently count as inactive.
+  if (config.plugin !== undefined && !Array.isArray(config.plugin)) {
+    throw new Error(`Invalid ${relativePath}: plugin must be an array`);
+  }
   return !Array.isArray(config.plugin) || !config.plugin.includes('./plugins');
 }
 
diff --git a/scripts/lib/install/hook-consent.js b/scripts/lib/install/hook-consent.js
index 689bd25e6..07cff400e 100644
--- a/scripts/lib/install/hook-consent.js
+++ b/scripts/lib/install/hook-consent.js
@@ -65,6 +65,10 @@ function parseJsoncConfig(content, sourceRelativePath) {
   return config;
 }
 
+function isLineBreak(ch) {
+  return ch === '\n' || ch === '\r';
+}
+
 /**
  * Advance past whitespace and // or /* *\/ comments; returns the index of
  * the next significant character.
@@ -74,12 +78,13 @@ function skipJsoncTrivia(input, start) {
   for (;;) {
     while (j < input.length && /\s/.test(input[j])) j += 1;
     if (input[j] === '/' && input[j + 1] === '/') {
-      while (j < input.length && input[j] !== '\n') j += 1;
+      while (j < input.length && !isLineBreak(input[j])) j += 1;
       continue;
     }
     if (input[j] === '/' && input[j + 1] === '*') {
       j += 2;
       while (j < input.length && !(input[j] === '*' && input[j + 1] === '/')) j += 1;
+      if (j >= input.length) throw new Error('Unterminated block comment');
       j += 2;
       continue;
     }
@@ -110,13 +115,14 @@ function stripJsonc(input) {
       continue;
     }
     if (ch === '/' && input[i + 1] === '/') {
-      while (i < input.length && input[i] !== '\n') i += 1;
+      while (i < input.length && !isLineBreak(input[i])) i += 1;
       out += '\n';
       continue;
     }
     if (ch === '/' && input[i + 1] === '*') {
       i += 2;
       while (i < input.length && !(input[i] === '*' && input[i + 1] === '/')) i += 1;
+      if (i >= input.length) throw new Error('Unterminated block comment');
       i += 1; // consume the closing '/'
       out += ' ';
       continue;
diff --git a/tests/lib/opencode-hook-consent-safety.test.js b/tests/lib/opencode-hook-consent-safety.test.js
index bb4389a25..a068d2a14 100644
--- a/tests/lib/opencode-hook-consent-safety.test.js
+++ b/tests/lib/opencode-hook-consent-safety.test.js
@@ -248,6 +248,20 @@ function runTests() {
       assert.strictEqual(fs.readFileSync(destination, 'utf8'), '{ malformed');
       assert.deepStrictEqual(fs.readFileSync(value.installStatePath), before);
     }));
+    test(`${mode} reports a non-array plugin with source context`, () => fixture(value => {
+      const destination = path.join(value.targetRoot, 'opencode.json');
+      fs.writeFileSync(destination, '{"plugin":"./plugins"}');
+      const before = fs.readFileSync(value.installStatePath);
+      if (mode === 'apply') assert.throws(() => applyInstallPlan(value.declinePlan), /Invalid .*opencode\.json: plugin must be an array/);
+      else if (mode === 'repair') assert.match(repair(value).results[0].error, /plugin must be an array/);
+      else {
+        const result = buildDoctorReport({ repoRoot: value.sourceRoot, homeDir: value.homeDir,
+          projectRoot: value.homeDir, targets: ['opencode'] }).results[0];
+        assert.match(JSON.stringify(result.issues), /plugin must be an array/);
+      }
+      assert.strictEqual(fs.readFileSync(destination, 'utf8'), '{"plugin":"./plugins"}');
+      assert.deepStrictEqual(fs.readFileSync(value.installStatePath), before);
+    }));
   }
   test('apply rejects another enabled writer and repair while holding its target lease', () => fixture(value => {
     let checked = false;
@@ -328,6 +342,16 @@ function runTests() {
       assert.strictEqual(config.endpoint, 'https://example.com/path');
       assert.strictEqual(config.block, '/* not a comment */');
     });
+    test('parseJsoncConfig rejects an unterminated block comment with source context', () => {
+      assert.throws(
+        () => parseJsoncConfig('{"plugin":[]} /* unfinished', 'opencode.json'),
+        /Failed to parse opencode\.json: Unterminated block comment/,
+      );
+    });
+    test('parseJsoncConfig stops line comments at CR-only line endings', () => {
+      const config = parseJsoncConfig('{"plugin":[] // note\r}', 'opencode.json');
+      assert.deepStrictEqual(config.plugin, []);
+    });
     test(`fresh ${consent || 'default'} apply preserves inactive JSONC user config with comments`, () => fixture(value => {
       fs.unlinkSync(value.installStatePath);
       fs.unlinkSync(path.join(value.targetRoot, 'plugins/ecc-hooks.ts'));