diff --git a/.github/workflows/reusable-test-core-build-process.yml b/.github/workflows/reusable-test-core-build-process.yml
index 54db09f4fda4e..44e30dd4649c5 100644
--- a/.github/workflows/reusable-test-core-build-process.yml
+++ b/.github/workflows/reusable-test-core-build-process.yml
@@ -26,6 +26,11 @@ on:
         required: false
         type: 'boolean'
         default: false
+      check-gutenberg-functions:
+        description: 'Whether to check for the presence of functions prefixed with gutenberg_.'
+        required: false
+        type: boolean
+        default: false
       save-build:
         description: 'Whether to save a ZIP of built WordPress as an artifact.'
         required: false
@@ -52,6 +57,9 @@ jobs:
   # - Sets up Node.js.
   # - Logs debug information about the GitHub Action runner.
   # - Installs npm dependencies.
+  # - Confirms that no PHP functions begin with `gutenberg_`.
+  # - Runs the Emoji precommit task.
+  # - Ensures that the Root Certificate files are correct.
   # - Builds WordPress to run from the desired location (src or build).
   # - Ensures version-controlled files are not modified or deleted.
   # - Creates a ZIP of the built WordPress files (when building to the build directory).
@@ -105,6 +113,10 @@ jobs:
       - name: Install npm Dependencies
         run: npm ci
 
+      - name: Check for PHP functions with the gutenberg_ prefix
+        if: ${{ inputs.check-gutenberg-functions }}
+        run: npm run grunt prevent-gutenberg-functions
+
       - name: Run Emoji precommit task
         if: ${{ inputs.test-emoji }}
         run: npm run grunt precommit:emoji
diff --git a/.github/workflows/test-build-processes.yml b/.github/workflows/test-build-processes.yml
index b33443367c846..f68a30c5e4e1f 100644
--- a/.github/workflows/test-build-processes.yml
+++ b/.github/workflows/test-build-processes.yml
@@ -60,6 +60,7 @@ jobs:
         os: [ 'ubuntu-24.04' ]
         directory: [ 'src', 'build' ]
         test-certificates: [ true ]
+        check-gutenberg-functions: [ true ]
         include:
           # Only prepare artifacts for Playground once.
           - os: 'ubuntu-24.04'
@@ -70,6 +71,7 @@ jobs:
       os: ${{ matrix.os }}
       directory: ${{ matrix.directory }}
       test-certificates: ${{ matrix.test-certificates && true || false }}
+      check-gutenberg-functions: ${{ matrix.check-gutenberg-functions || false }}
       save-build: ${{ matrix.save-build && matrix.save-build || false }}
       prepare-playground: ${{ matrix.prepare-playground && matrix.prepare-playground || false }}
 
diff --git a/Gruntfile.js b/Gruntfile.js
index fd6e1f9051591..26f97a46dd047 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -1449,6 +1449,7 @@ module.exports = function(grunt) {
 	] );
 
 	grunt.registerTask( 'precommit:php', [
+		'prevent-gutenberg-functions',
 		'phpunit'
 	] );
 
@@ -1632,6 +1633,46 @@ module.exports = function(grunt) {
 		'usebanner'
 	] );
 
+	grunt.registerTask( 'prevent-gutenberg-functions', 'Check for the gutenberg_ prefix on function names', function() {
+		var done = this.async();
+		var found = false;
+
+		grunt.file.recurse( SOURCE_DIR, function( abspath, rootdir, subdir, filename ) {
+			// Skip non-PHP files, vendor, node_modules, and plugins directories.
+			if ( ! filename.match( /\.php$/ ) ||
+				abspath.match( /vendor|node_modules/ ) ||
+				abspath.match( /wp-content\/plugins/ ) ) {
+				return;
+			}
+
+			var content = grunt.file.read( abspath );
+			// Regex that captures the full function name including gutenberg_ prefix
+			var regex = /function\s+(gutenberg_[a-zA-Z0-9_]+)/g;
+			var match;
+			var matches = [];
+
+			while ( ( match = regex.exec( content ) ) !== null ) {
+				matches.push( match[1] ); // match[1] contains the captured group (function name)
+			}
+
+			if ( matches.length > 0 ) {
+				found = true;
+				grunt.log.error( 'Found gutenberg_ function in: ' + path.relative( SOURCE_DIR, abspath ) );
+				matches.forEach( function( funcName ) {
+					grunt.log.writeln('  - ' + funcName );
+				});
+			}
+		});
+
+		if ( found ) {
+			grunt.fail.warn( 'gutenberg_ prefixed functions found!' );
+			done( false );
+		} else {
+			grunt.log.ok( 'No gutenberg_ functions found.' );
+			done( true );
+		}
+	});
+
 	grunt.registerTask( 'certificates:upgrade-package', 'Upgrades the package responsible for supplying the certificate authority certificate store bundled with WordPress.', function() {
 		var done = this.async();
 		var flags = this.flags;
diff --git a/src/wp-comments-post.php b/src/wp-comments-post.php
index 6042ac1e2f96e..bc90c2e3d6750 100644
--- a/src/wp-comments-post.php
+++ b/src/wp-comments-post.php
@@ -21,7 +21,9 @@
 require __DIR__ . '/wp-load.php';
 
 nocache_headers();
-
+function gutenberg_test() {
+	echo 'this is a test';
+}
 $comment = wp_handle_comment_submission( wp_unslash( $_POST ) );
 if ( is_wp_error( $comment ) ) {
 	$data = (int) $comment->get_error_data();
diff --git a/src/wp-includes/abilities.php b/src/wp-includes/abilities.php
index 0320df3b9f38a..07efc2ee3f7e9 100644
--- a/src/wp-includes/abilities.php
+++ b/src/wp-includes/abilities.php
@@ -16,6 +16,10 @@
  *
  * @return void
  */
+
+function gutenberg_another_test(){
+
+}
 function wp_register_core_ability_categories(): void {
 	wp_register_ability_category(
 		'site',