diff --git a/src/scheduler/AsyncPool.php b/src/scheduler/AsyncPool.php
index 5ac526afc0..a33740bb3d 100644
--- a/src/scheduler/AsyncPool.php
+++ b/src/scheduler/AsyncPool.php
@@ -57,7 +57,10 @@ class AsyncPool{
 	/** @var int[] */
 	private $workerLastUsed = [];
 
-	/** @var \Closure[] */
+	/**
+	 * @var \Closure[]
+	 * @phpstan-var (\Closure(int $workerId) : void)[]
+	 */
 	private $workerStartHooks = [];
 
 	public function __construct(int $size, int $workerMemoryLimit, \ClassLoader $classLoader, \ThreadedLogger $logger){
@@ -88,6 +91,8 @@ class AsyncPool{
 	 * The signature should be `function(int $worker) : void`
 	 *
 	 * This function will call the hook for every already-running worker.
+	 *
+	 * @phpstan-param \Closure(int $workerId) : void $hook
 	 */
 	public function addWorkerStartHook(\Closure $hook) : void{
 		Utils::validateCallableSignature(function(int $worker) : void{}, $hook);
@@ -99,6 +104,8 @@ class AsyncPool{
 
 	/**
 	 * Removes a previously-registered callback listening for workers being started.
+	 *
+	 * @phpstan-param \Closure(int $workerId) : void $hook
 	 */
 	public function removeWorkerStartHook(\Closure $hook) : void{
 		unset($this->workerStartHooks[spl_object_id($hook)]);
diff --git a/src/scheduler/ClosureTask.php b/src/scheduler/ClosureTask.php
index f306143d27..6152469c05 100644
--- a/src/scheduler/ClosureTask.php
+++ b/src/scheduler/ClosureTask.php
@@ -38,11 +38,15 @@ use pocketmine\utils\Utils;
  */
 class ClosureTask extends Task{
 
-	/** @var \Closure */
+	/**
+	 * @var \Closure
+	 * @phpstan-var \Closure(int) : void
+	 */
 	private $closure;
 
 	/**
 	 * @param \Closure $closure Must accept only ONE parameter, $currentTick
+	 * @phpstan-param \Closure(int) : void $closure
 	 */
 	public function __construct(\Closure $closure){
 		Utils::validateCallableSignature(function(int $currentTick){}, $closure);
diff --git a/src/utils/Internet.php b/src/utils/Internet.php
index c2ce7c14ed..fd9bc92fd2 100644
--- a/src/utils/Internet.php
+++ b/src/utils/Internet.php
@@ -183,6 +183,7 @@ class Internet{
 	 * @param string[]      $extraHeaders extra headers to send as a plain string array
 	 * @param array         $extraOpts extra CURLOPT_* to set as an [opt => value] map
 	 * @param \Closure|null $onSuccess function to be called if there is no error. Accepts a resource argument as the cURL handle.
+	 * @phpstan-param (\Closure(resource) : void)|null $onSuccess
 	 *
 	 * @return array a plain array of three [result body : string, headers : array[], HTTP response code : int]. Headers are grouped by requests with strtolower(header name) as keys and header value as values
 	 *