diff --git a/.github/workflows/harness.yml b/.github/workflows/harness.yml
index 623ab53..ad6e301 100644
--- a/.github/workflows/harness.yml
+++ b/.github/workflows/harness.yml
@@ -14,6 +14,6 @@ permissions: {}
 
 jobs:
   harness:
-    uses: Pollora/harness/.github/workflows/php-package.yml@v0.1.6
+    uses: Pollora/harness/.github/workflows/php-package.yml@v0.1.8
     permissions:
       contents: read
diff --git a/.harness.json b/.harness.json
index cf53aca..8d7459b 100644
--- a/.harness.json
+++ b/.harness.json
@@ -7,8 +7,5 @@
     "ratchet": {
         "phpstan_level": 8,
         "phpstan_baseline": 0
-    },
-    "observed": [
-        "Rector"
-    ]
+    }
 }
diff --git a/composer.json b/composer.json
index f2a9324..26c7069 100644
--- a/composer.json
+++ b/composer.json
@@ -26,7 +26,7 @@
         "mockery/mockery": "^1.6",
         "pestphp/pest": "^3.8",
         "phpstan/phpstan": "^2.1",
-        "pollora/harness": "^0.1.6"
+        "pollora/harness": "^0.1.8"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/Factory/PendingAbility.php b/src/Factory/PendingAbility.php
index bbe7ffd..919429f 100644
--- a/src/Factory/PendingAbility.php
+++ b/src/Factory/PendingAbility.php
@@ -50,7 +50,7 @@ final class PendingAbility
     /**
      * Builder holding the declared input properties.
      */
-    private SchemaBuilder $schema;
+    private readonly SchemaBuilder $schema;
 
     /**
      * JSON Schema of the returned value, or null to leave the output undescribed.