diff --git a/CHANGELOG.md b/CHANGELOG.md
index 14a633a5..8f222d9c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@ Latest
 ## Changes
 * [#90](https://github.com/cleverage/process-bundle/issues/90) Installation documentation: describe the Symfony Flex recipe ([symfony/recipes-contrib#2081](https://github.com/symfony/recipes-contrib/pull/2081)), which registers the bundle and creates `config/packages/clever_age_process.yaml` importing the `config/packages/process/` directory, and the manual setup without Flex.
 
+## Fixes
+* [#327](https://github.com/cleverage/process-bundle/issues/327) `ContextualOptionResolver`: quote the context keys in the pattern of the `{{ key }}` placeholders (a key containing `/` made every string option fail, a key containing a regex character matched other placeholders), and leave the options as is with an empty context (`{{ }}` matched an empty key).
+
 v5.4
 -----
 
diff --git a/src/Context/ContextualOptionResolver.php b/src/Context/ContextualOptionResolver.php
index f4d67677..4e066f8c 100644
--- a/src/Context/ContextualOptionResolver.php
+++ b/src/Context/ContextualOptionResolver.php
@@ -31,8 +31,11 @@ public function contextualizeOption(mixed $value, array $context): mixed
             return $this->contextualizeOptions($value, $context);
         }
 
-        if (\is_string($value)) {
-            $pattern = \sprintf('/{{[ ]*(%s){1}[ ]*}}/', implode('|', array_keys($context)));
+        // Without context, there is nothing to replace ("{{ }}" would match an empty key)
+        if (\is_string($value) && [] !== $context) {
+            // The keys are free (console, process_executor, UI...): quoted, they cannot alter the pattern
+            $keys = array_map(static fn (int|string $key): string => preg_quote((string) $key, '/'), array_keys($context));
+            $pattern = \sprintf('/{{[ ]*(%s){1}[ ]*}}/', implode('|', $keys));
 
             $matches = [];
             $result = preg_match($pattern, $value, $matches);
diff --git a/tests/Context/ContextualOptionResolverTest.php b/tests/Context/ContextualOptionResolverTest.php
new file mode 100644
index 00000000..0024086f
--- /dev/null
+++ b/tests/Context/ContextualOptionResolverTest.php
@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the CleverAge/ProcessBundle package.
+ *
+ * Copyright (c) Clever-Age
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace CleverAge\ProcessBundle\Tests\Context;
+
+use CleverAge\ProcessBundle\Context\ContextualOptionResolver;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+
+#[CoversClass(ContextualOptionResolver::class)]
+class ContextualOptionResolverTest extends TestCase
+{
+    public function testExactMatchReturnsTheContextValue(): void
+    {
+        self::assertSame(['a', 'b'], (new ContextualOptionResolver())->contextualizeOption('{{ ids }}', ['ids' => ['a', 'b']]));
+    }
+
+    public function testPlaceholdersAreReplacedInStrings(): void
+    {
+        self::assertSame(
+            ['path' => 'var/data/books.csv', 'other' => 'no placeholder', 'books' => 1],
+            (new ContextualOptionResolver())->contextualizeOptions(
+                ['path' => 'var/{{dir}}/{{ name }}.csv', 'other' => 'no placeholder', '{{ name }}' => 1],
+                ['dir' => 'data', 'name' => 'books']
+            )
+        );
+    }
+
+    /**
+     * The context keys are free (console, process_executor, UI...): they must not alter the pattern.
+     */
+    public function testContextKeysAreQuoted(): void
+    {
+        $resolver = new ContextualOptionResolver();
+
+        // A "/" made the pattern invalid, for every string option
+        self::assertSame('value', $resolver->contextualizeOption('{{ a/b }}', ['a/b' => 'value']));
+        self::assertSame('no placeholder', $resolver->contextualizeOption('no placeholder', ['a/b' => 'value']));
+        // "x." matched "{{ x }}"
+        self::assertSame('{{ x }}', $resolver->contextualizeOption('{{ x }}', ['x.' => 'value']));
+        self::assertSame('value', $resolver->contextualizeOption('{{ x. }}', ['x.' => 'value']));
+    }
+
+    public function testEmptyContext(): void
+    {
+        // "{{ }}" matched an empty key
+        self::assertSame('{{ }} {{ name }}', (new ContextualOptionResolver())->contextualizeOption('{{ }} {{ name }}', []));
+    }
+
+    public function testNonStringValuesAreKept(): void
+    {
+        self::assertSame(12, (new ContextualOptionResolver())->contextualizeOption(12, ['name' => 'books']));
+    }
+}