diff --git a/psalm.xml b/psalm.xml
index 510148d..feccc34 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -14,4 +14,7 @@
             <directory name="vendor" />
         </ignoreFiles>
     </projectFiles>
+    <issueHandlers>
+        <UndefinedAttributeClass errorLevel="suppress" />
+    </issueHandlers>
 </psalm>
diff --git a/src/Crontab.php b/src/Crontab.php
index d04acc4..7fd5901 100644
--- a/src/Crontab.php
+++ b/src/Crontab.php
@@ -41,6 +41,7 @@ private function __construct(Command $command, Job ...$jobs)
     /**
      * @return Attempt<SideEffect>
      */
+    #[\NoDiscard]
     public function __invoke(Server $server): Attempt
     {
         $installOn = Script::of($this->command);
@@ -52,6 +53,7 @@ public function __invoke(Server $server): Attempt
      * @no-named-arguments
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function forConnectedUser(Job ...$jobs): self
     {
         return new self(Command::foreground('crontab'), ...$jobs);
@@ -63,6 +65,7 @@ public static function forConnectedUser(Job ...$jobs): self
      *
      * @param non-empty-string $user
      */
+    #[\NoDiscard]
     public static function forUser(string $user, Job ...$jobs): self
     {
         return new self(
diff --git a/src/Job.php b/src/Job.php
index 8f3781e..bb7be70 100644
--- a/src/Job.php
+++ b/src/Job.php
@@ -32,6 +32,7 @@ public function __construct(Schedule $schedule, Command $command)
      *
      * @throws \DomainException
      */
+    #[\NoDiscard]
     public static function of(string $value): self
     {
         return self::attempt($value)->unwrap();
@@ -42,6 +43,7 @@ public static function of(string $value): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $value): Maybe
     {
         return self::attempt($value)->maybe();
@@ -52,6 +54,7 @@ public static function maybe(string $value): Maybe
      *
      * @return Attempt<self>
      */
+    #[\NoDiscard]
     public static function attempt(string $value): Attempt
     {
         $parts = Str::of($value)
@@ -78,6 +81,7 @@ public static function attempt(string $value): Attempt
             )));
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         $command = $this->command->environment()->reduce(
diff --git a/src/Job/Schedule.php b/src/Job/Schedule.php
index 8a43ae3..51fbf2a 100644
--- a/src/Job/Schedule.php
+++ b/src/Job/Schedule.php
@@ -47,6 +47,7 @@ public function __construct(
      *
      * @throws \DomainException
      */
+    #[\NoDiscard]
     public static function of(string $value): self
     {
         return self::maybe($value)->match(
@@ -60,6 +61,7 @@ public static function of(string $value): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $value): Maybe
     {
         $parts = Str::of($value)->split(' ');
@@ -104,6 +106,7 @@ public static function maybe(string $value): Maybe
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function everyMinute(): self
     {
         return new self(
@@ -120,6 +123,7 @@ public static function everyMinute(): self
      *
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function everyHourAt(int $minute): self
     {
         return new self(
@@ -137,6 +141,7 @@ public static function everyHourAt(int $minute): self
      * @param int<0, 23> $hour
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function everyDayAt(int $hour, int $minute): self
     {
         return new self(
@@ -154,6 +159,7 @@ public static function everyDayAt(int $hour, int $minute): self
      * @param int<0, 23> $hour
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function everyMondayAt(int $hour, int $minute): self
     {
         return new self(
@@ -171,6 +177,7 @@ public static function everyMondayAt(int $hour, int $minute): self
      * @param int<0, 23> $hour
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function everyTuesdayAt(int $hour, int $minute): self
     {
         return new self(
@@ -188,6 +195,7 @@ public static function everyTuesdayAt(int $hour, int $minute): self
      * @param int<0, 23> $hour
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function everyWednesdayAt(int $hour, int $minute): self
     {
         return new self(
@@ -205,6 +213,7 @@ public static function everyWednesdayAt(int $hour, int $minute): self
      * @param int<0, 23> $hour
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function everyThursdayAt(int $hour, int $minute): self
     {
         return new self(
@@ -222,6 +231,7 @@ public static function everyThursdayAt(int $hour, int $minute): self
      * @param int<0, 23> $hour
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function everyFridayAt(int $hour, int $minute): self
     {
         return new self(
@@ -239,6 +249,7 @@ public static function everyFridayAt(int $hour, int $minute): self
      * @param int<0, 23> $hour
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function everySaturdayAt(int $hour, int $minute): self
     {
         return new self(
@@ -256,6 +267,7 @@ public static function everySaturdayAt(int $hour, int $minute): self
      * @param int<0, 23> $hour
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function everySundayAt(int $hour, int $minute): self
     {
         return new self(
@@ -267,6 +279,7 @@ public static function everySundayAt(int $hour, int $minute): self
         );
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return \sprintf(
diff --git a/src/Job/Schedule/DaysOfMonth.php b/src/Job/Schedule/DaysOfMonth.php
index 23f1e6c..455e588 100644
--- a/src/Job/Schedule/DaysOfMonth.php
+++ b/src/Job/Schedule/DaysOfMonth.php
@@ -24,6 +24,7 @@ private function __construct(string $value)
      *
      * @throws \DomainException
      */
+    #[\NoDiscard]
     public static function of(string $value): self
     {
         return self::maybe($value)->match(
@@ -37,6 +38,7 @@ public static function of(string $value): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $value): Maybe
     {
         return Maybe::just($value)
@@ -47,6 +49,7 @@ public static function maybe(string $value): Maybe
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function each(): self
     {
         return new self('*');
@@ -57,11 +60,13 @@ public static function each(): self
      *
      * @param int<1, 31> $day
      */
+    #[\NoDiscard]
     public static function at(int $day): self
     {
         return new self((string) $day);
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this->value;
diff --git a/src/Job/Schedule/DaysOfWeek.php b/src/Job/Schedule/DaysOfWeek.php
index 0361dbf..337062c 100644
--- a/src/Job/Schedule/DaysOfWeek.php
+++ b/src/Job/Schedule/DaysOfWeek.php
@@ -24,6 +24,7 @@ private function __construct(string $value)
      *
      * @throws \DomainException
      */
+    #[\NoDiscard]
     public static function of(string $value): self
     {
         return self::maybe($value)->match(
@@ -37,6 +38,7 @@ public static function of(string $value): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $value): Maybe
     {
         return Maybe::just($value)
@@ -47,6 +49,7 @@ public static function maybe(string $value): Maybe
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function each(): self
     {
         return new self('*');
@@ -57,11 +60,13 @@ public static function each(): self
      *
      * @param int<0, 6> $day
      */
+    #[\NoDiscard]
     public static function at(int $day): self
     {
         return new self((string) $day);
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this->value;
diff --git a/src/Job/Schedule/Hours.php b/src/Job/Schedule/Hours.php
index d8d5ca8..3b12a32 100644
--- a/src/Job/Schedule/Hours.php
+++ b/src/Job/Schedule/Hours.php
@@ -24,6 +24,7 @@ private function __construct(string $value)
      *
      * @throws \DomainException
      */
+    #[\NoDiscard]
     public static function of(string $value): self
     {
         return self::maybe($value)->match(
@@ -37,6 +38,7 @@ public static function of(string $value): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $value): Maybe
     {
         return Maybe::just($value)
@@ -47,6 +49,7 @@ public static function maybe(string $value): Maybe
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function each(): self
     {
         return new self('*');
@@ -57,11 +60,13 @@ public static function each(): self
      *
      * @param int<0, 23> $hour
      */
+    #[\NoDiscard]
     public static function at(int $hour): self
     {
         return new self((string) $hour);
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this->value;
diff --git a/src/Job/Schedule/Minutes.php b/src/Job/Schedule/Minutes.php
index e504485..b4da411 100644
--- a/src/Job/Schedule/Minutes.php
+++ b/src/Job/Schedule/Minutes.php
@@ -24,6 +24,7 @@ private function __construct(string $value)
      *
      * @throws \DomainException
      */
+    #[\NoDiscard]
     public static function of(string $value): self
     {
         return self::maybe($value)->match(
@@ -37,6 +38,7 @@ public static function of(string $value): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $value): Maybe
     {
         return Maybe::just($value)
@@ -47,6 +49,7 @@ public static function maybe(string $value): Maybe
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function each(): self
     {
         return new self('*');
@@ -57,11 +60,13 @@ public static function each(): self
      *
      * @param int<0, 59> $minute
      */
+    #[\NoDiscard]
     public static function at(int $minute): self
     {
         return new self((string) $minute);
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this->value;
diff --git a/src/Job/Schedule/Months.php b/src/Job/Schedule/Months.php
index 5976024..9c527d9 100644
--- a/src/Job/Schedule/Months.php
+++ b/src/Job/Schedule/Months.php
@@ -24,6 +24,7 @@ private function __construct(string $value)
      *
      * @throws \DomainException
      */
+    #[\NoDiscard]
     public static function of(string $value): self
     {
         return self::maybe($value)->match(
@@ -37,6 +38,7 @@ public static function of(string $value): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $value): Maybe
     {
         return Maybe::just($value)
@@ -47,6 +49,7 @@ public static function maybe(string $value): Maybe
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function each(): self
     {
         return new self('*');
@@ -57,11 +60,13 @@ public static function each(): self
      *
      * @param int<1, 12> $month
      */
+    #[\NoDiscard]
     public static function at(int $month): self
     {
         return new self((string) $month);
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this->value;
diff --git a/src/Job/Schedule/Range.php b/src/Job/Schedule/Range.php
index 72e34ca..8e147f7 100644
--- a/src/Job/Schedule/Range.php
+++ b/src/Job/Schedule/Range.php
@@ -18,6 +18,7 @@ public function __construct(string $pattern)
         $this->pattern = $pattern;
     }
 
+    #[\NoDiscard]
     public function __invoke(string $value): bool
     {
         if ($value === '*') {
diff --git a/src/Read.php b/src/Read.php
index de25d8d..4ba0a13 100644
--- a/src/Read.php
+++ b/src/Read.php
@@ -26,6 +26,7 @@ private function __construct(Command $command)
     /**
      * @return Attempt<Sequence<Job>>
      */
+    #[\NoDiscard]
     public function __invoke(Server $server): Attempt
     {
         return $server
@@ -59,6 +60,7 @@ public function __invoke(Server $server): Attempt
         );
     }
 
+    #[\NoDiscard]
     public static function forConnectedUser(): self
     {
         return new self(
@@ -70,6 +72,7 @@ public static function forConnectedUser(): self
     /**
      * @param non-empty-string $user
      */
+    #[\NoDiscard]
     public static function forUser(string $user): self
     {
         return new self(