diff --git a/psalm.xml b/psalm.xml
index 510148d8..feccc34e 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/Content/Multipart.php b/src/Content/Multipart.php
index 18362691..33effc49 100644
--- a/src/Content/Multipart.php
+++ b/src/Content/Multipart.php
@@ -34,6 +34,7 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function boundary(Boundary $boundary): self
     {
         /** @var Sequence<Data|File> */
@@ -42,6 +43,7 @@ public static function boundary(Boundary $boundary): self
         return new self($boundary, $parts);
     }
 
+    #[\NoDiscard]
     public function with(string $name, string $data): self
     {
         return new self(
@@ -50,6 +52,7 @@ public function with(string $name, string $data): self
         );
     }
 
+    #[\NoDiscard]
     public function withFile(string $name, Binary $file): self
     {
         return new self(
@@ -58,6 +61,7 @@ public function withFile(string $name, Binary $file): self
         );
     }
 
+    #[\NoDiscard]
     public function asContent(): Content
     {
         return Content::ofChunks($this->chunks());
diff --git a/src/Factory/CookiesFactory.php b/src/Factory/CookiesFactory.php
index c2ea570f..5b10e1e6 100644
--- a/src/Factory/CookiesFactory.php
+++ b/src/Factory/CookiesFactory.php
@@ -21,11 +21,13 @@ private function __construct(
     ) {
     }
 
+    #[\NoDiscard]
     public function __invoke(): Cookies
     {
         return ($this->implementation)();
     }
 
+    #[\NoDiscard]
     public static function native(): self
     {
         return new self(Native::new());
@@ -36,6 +38,7 @@ public static function native(): self
      *
      * @param pure-Closure(): Cookies $factory
      */
+    #[\NoDiscard]
     public static function of(\Closure $factory): self
     {
         return new self($factory);
diff --git a/src/Factory/EnvironmentFactory.php b/src/Factory/EnvironmentFactory.php
index aee5dcea..9f417e7c 100644
--- a/src/Factory/EnvironmentFactory.php
+++ b/src/Factory/EnvironmentFactory.php
@@ -21,11 +21,13 @@ private function __construct(
     ) {
     }
 
+    #[\NoDiscard]
     public function __invoke(): Environment
     {
         return ($this->implementation)();
     }
 
+    #[\NoDiscard]
     public static function native(): self
     {
         return new self(Native::new());
@@ -36,6 +38,7 @@ public static function native(): self
      *
      * @param pure-Closure(): Environment $factory
      */
+    #[\NoDiscard]
     public static function of(\Closure $factory): self
     {
         return new self($factory);
diff --git a/src/Factory/FilesFactory.php b/src/Factory/FilesFactory.php
index 5a4a61d1..ad1f13e6 100644
--- a/src/Factory/FilesFactory.php
+++ b/src/Factory/FilesFactory.php
@@ -22,11 +22,13 @@ private function __construct(
     ) {
     }
 
+    #[\NoDiscard]
     public function __invoke(): Files
     {
         return ($this->implementation)();
     }
 
+    #[\NoDiscard]
     public static function native(IO $io): self
     {
         return new self(Native::new($io));
@@ -37,6 +39,7 @@ public static function native(IO $io): self
      *
      * @param pure-Closure(): Files $factory
      */
+    #[\NoDiscard]
     public static function of(\Closure $factory): self
     {
         return new self($factory);
diff --git a/src/Factory/FormFactory.php b/src/Factory/FormFactory.php
index 55022f0e..53e90be3 100644
--- a/src/Factory/FormFactory.php
+++ b/src/Factory/FormFactory.php
@@ -21,11 +21,13 @@ private function __construct(
     ) {
     }
 
+    #[\NoDiscard]
     public function __invoke(): Form
     {
         return ($this->implementation)();
     }
 
+    #[\NoDiscard]
     public static function native(): self
     {
         return new self(Native::new());
@@ -36,6 +38,7 @@ public static function native(): self
      *
      * @param pure-Closure(): Form $factory
      */
+    #[\NoDiscard]
     public static function of(\Closure $factory): self
     {
         return new self($factory);
diff --git a/src/Factory/HeadersFactory.php b/src/Factory/HeadersFactory.php
index 20684443..3a965af0 100644
--- a/src/Factory/HeadersFactory.php
+++ b/src/Factory/HeadersFactory.php
@@ -22,11 +22,13 @@ private function __construct(
     ) {
     }
 
+    #[\NoDiscard]
     public function __invoke(): Headers
     {
         return ($this->implementation)();
     }
 
+    #[\NoDiscard]
     public static function native(Clock $clock): self
     {
         return new self(Native::new($clock));
@@ -37,6 +39,7 @@ public static function native(Clock $clock): self
      *
      * @param pure-Closure(): Headers $factory
      */
+    #[\NoDiscard]
     public static function of(\Closure $factory): self
     {
         return new self($factory);
diff --git a/src/Factory/QueryFactory.php b/src/Factory/QueryFactory.php
index 61ed1bd5..3c54b6de 100644
--- a/src/Factory/QueryFactory.php
+++ b/src/Factory/QueryFactory.php
@@ -21,11 +21,13 @@ private function __construct(
     ) {
     }
 
+    #[\NoDiscard]
     public function __invoke(): Query
     {
         return ($this->implementation)();
     }
 
+    #[\NoDiscard]
     public static function native(): self
     {
         return new self(Native::new());
@@ -36,6 +38,7 @@ public static function native(): self
      *
      * @param pure-Closure(): Query $factory
      */
+    #[\NoDiscard]
     public static function of(\Closure $factory): self
     {
         return new self($factory);
diff --git a/src/Factory/ServerRequestFactory.php b/src/Factory/ServerRequestFactory.php
index 7fb75a38..7cb41ff5 100644
--- a/src/Factory/ServerRequestFactory.php
+++ b/src/Factory/ServerRequestFactory.php
@@ -39,6 +39,7 @@ private function __construct(
     ) {
     }
 
+    #[\NoDiscard]
     public function __invoke(): ServerRequest
     {
         /** @psalm-suppress MixedArgument */
@@ -94,6 +95,7 @@ public function __invoke(): ServerRequest
     /**
      * Return a fully configured factory
      */
+    #[\NoDiscard]
     public static function native(
         Clock $clock,
         ?IO $io = null,
@@ -125,6 +127,7 @@ public static function native(
      * @param \Closure(): Content $bodyFactory
      * @param array<string, string> $server
      */
+    #[\NoDiscard]
     public static function of(
         HeadersFactory $headersFactory,
         \Closure $bodyFactory,
diff --git a/src/Header.php b/src/Header.php
index c594eb64..3d4e7ccd 100644
--- a/src/Header.php
+++ b/src/Header.php
@@ -27,11 +27,13 @@ private function __construct(
      * @psalm-pure
      * @no-named-arguments
      */
+    #[\NoDiscard]
     public static function of(string $name, Value ...$values): self
     {
         return new self($name, Sequence::of(...$values));
     }
 
+    #[\NoDiscard]
     public function name(): string
     {
         return $this->name;
@@ -40,11 +42,13 @@ public function name(): string
     /**
      * @return Sequence<Value>
      */
+    #[\NoDiscard]
     public function values(): Sequence
     {
         return $this->values;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         $values = $this->values->map(static fn($value) => $value->toString());
diff --git a/src/Header/Accept.php b/src/Header/Accept.php
index eee0eaf9..9de079af 100644
--- a/src/Header/Accept.php
+++ b/src/Header/Accept.php
@@ -25,12 +25,14 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(MediaType $first, MediaType ...$values): self
     {
         return new self(Sequence::of($first, ...$values));
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/Accept/Charset.php b/src/Header/Accept/Charset.php
index 324484d2..516852cf 100644
--- a/src/Header/Accept/Charset.php
+++ b/src/Header/Accept/Charset.php
@@ -25,6 +25,7 @@ private function __construct(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $charset, ?Quality $quality = null): Maybe
     {
         $charset = Str::of($charset);
@@ -40,11 +41,13 @@ public static function maybe(string $charset, ?Quality $quality = null): Maybe
         return Maybe::just(new self($charset, $quality ?? Quality::max()));
     }
 
+    #[\NoDiscard]
     public function quality(): Quality
     {
         return $this->quality;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this
diff --git a/src/Header/Accept/Encoding.php b/src/Header/Accept/Encoding.php
index bb0e085c..e44be739 100644
--- a/src/Header/Accept/Encoding.php
+++ b/src/Header/Accept/Encoding.php
@@ -25,6 +25,7 @@ private function __construct(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $coding, ?Quality $quality = null): Maybe
     {
         $coding = Str::of($coding);
@@ -40,11 +41,13 @@ public static function maybe(string $coding, ?Quality $quality = null): Maybe
         return Maybe::just(new self($coding, $quality ?? Quality::max()));
     }
 
+    #[\NoDiscard]
     public function quality(): Quality
     {
         return $this->quality;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this
diff --git a/src/Header/Accept/Language.php b/src/Header/Accept/Language.php
index 3c3aed0e..03a73887 100644
--- a/src/Header/Accept/Language.php
+++ b/src/Header/Accept/Language.php
@@ -25,6 +25,7 @@ private function __construct(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $language, ?Quality $quality = null): Maybe
     {
         $language = Str::of($language);
@@ -40,11 +41,13 @@ public static function maybe(string $language, ?Quality $quality = null): Maybe
         return Maybe::just(new self($language, $quality ?? Quality::max()));
     }
 
+    #[\NoDiscard]
     public function quality(): Quality
     {
         return $this->quality;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this
diff --git a/src/Header/Accept/MediaType.php b/src/Header/Accept/MediaType.php
index 82c701f7..f93767ab 100644
--- a/src/Header/Accept/MediaType.php
+++ b/src/Header/Accept/MediaType.php
@@ -28,6 +28,7 @@ private function __construct(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(
         string $type,
         string $subType,
@@ -57,11 +58,13 @@ public static function maybe(
         return Maybe::just(new self($type, $subType, $map));
     }
 
+    #[\NoDiscard]
     public function type(): string
     {
         return $this->type;
     }
 
+    #[\NoDiscard]
     public function subType(): string
     {
         return $this->subType;
@@ -70,11 +73,13 @@ public function subType(): string
     /**
      * @return Map<string, Parameter>
      */
+    #[\NoDiscard]
     public function parameters(): Map
     {
         return $this->parameters;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         $parameters = $this->parameters->values()->map(
diff --git a/src/Header/AcceptCharset.php b/src/Header/AcceptCharset.php
index f5ffa965..f7ef6cb4 100644
--- a/src/Header/AcceptCharset.php
+++ b/src/Header/AcceptCharset.php
@@ -26,12 +26,14 @@ private function __construct(
      * @psalm-pure
      * @no-named-arguments
      */
+    #[\NoDiscard]
     public static function of(Charset ...$charsets): self
     {
         return new self(Sequence::of(...$charsets));
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/AcceptEncoding.php b/src/Header/AcceptEncoding.php
index bf102f98..7b8c6e39 100644
--- a/src/Header/AcceptEncoding.php
+++ b/src/Header/AcceptEncoding.php
@@ -26,12 +26,14 @@ private function __construct(
      * @psalm-pure
      * @no-named-arguments
      */
+    #[\NoDiscard]
     public static function of(Encoding ...$encodings): self
     {
         return new self(Sequence::of(...$encodings));
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/AcceptLanguage.php b/src/Header/AcceptLanguage.php
index 96f2bcfe..ded5f0cf 100644
--- a/src/Header/AcceptLanguage.php
+++ b/src/Header/AcceptLanguage.php
@@ -26,12 +26,14 @@ private function __construct(
      * @psalm-pure
      * @no-named-arguments
      */
+    #[\NoDiscard]
     public static function of(Language ...$languages): self
     {
         return new self(Sequence::of(...$languages));
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/AcceptRanges.php b/src/Header/AcceptRanges.php
index 80123d41..b125edff 100644
--- a/src/Header/AcceptRanges.php
+++ b/src/Header/AcceptRanges.php
@@ -27,6 +27,7 @@ private function __construct(
      *
      * @throws DomainException
      */
+    #[\NoDiscard]
     public static function of(string $range): self
     {
         return self::maybe($range)->match(
@@ -40,6 +41,7 @@ public static function of(string $range): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $range): Maybe
     {
         return Maybe::just($range)
@@ -49,6 +51,7 @@ public static function maybe(string $range): Maybe
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/Age.php b/src/Header/Age.php
index 6a817739..f3d21470 100644
--- a/src/Header/Age.php
+++ b/src/Header/Age.php
@@ -24,6 +24,7 @@ private function __construct(
      *
      * @param int<0, max> $age
      */
+    #[\NoDiscard]
     public static function of(int $age): self
     {
         return new self($age);
@@ -34,6 +35,7 @@ public static function of(int $age): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(int $age): Maybe
     {
         return Maybe::of(match (true) {
@@ -45,12 +47,14 @@ public static function maybe(int $age): Maybe
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function age(): int
     {
         return $this->age;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of('Age', Value::of((string) $this->age));
diff --git a/src/Header/Allow.php b/src/Header/Allow.php
index 3e177bdf..82ed9f35 100644
--- a/src/Header/Allow.php
+++ b/src/Header/Allow.php
@@ -26,12 +26,14 @@ private function __construct(
      * @psalm-pure
      * @no-named-arguments
      */
+    #[\NoDiscard]
     public static function of(Method ...$methods): self
     {
         return new self(Sequence::of(...$methods));
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/Authorization.php b/src/Header/Authorization.php
index f84996c0..2726bd49 100644
--- a/src/Header/Authorization.php
+++ b/src/Header/Authorization.php
@@ -26,6 +26,7 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(string $scheme, string $parameter): self
     {
         return self::maybe($scheme, $parameter)->match(
@@ -39,6 +40,7 @@ public static function of(string $scheme, string $parameter): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $scheme, string $parameter): Maybe
     {
         return Maybe::just($scheme)
@@ -47,17 +49,20 @@ public static function maybe(string $scheme, string $parameter): Maybe
             ->map(static fn() => new self($scheme, $parameter));
     }
 
+    #[\NoDiscard]
     public function scheme(): string
     {
         return $this->scheme;
     }
 
+    #[\NoDiscard]
     public function parameter(): string
     {
         return $this->parameter;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/CacheControl.php b/src/Header/CacheControl.php
index 02a91838..7e892a64 100644
--- a/src/Header/CacheControl.php
+++ b/src/Header/CacheControl.php
@@ -32,6 +32,7 @@ private function __construct(
      * @psalm-pure
      * @no-named-arguments
      */
+    #[\NoDiscard]
     public static function of(
         Directive|MaxAge|MaxStale|MinimumFresh|NoCache|PrivateCache|SharedMaxAge $first,
         Directive|MaxAge|MaxStale|MinimumFresh|NoCache|PrivateCache|SharedMaxAge ...$values,
@@ -40,6 +41,7 @@ public static function of(
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/CacheControl/Directive.php b/src/Header/CacheControl/Directive.php
index 604f7927..3cc99e13 100644
--- a/src/Header/CacheControl/Directive.php
+++ b/src/Header/CacheControl/Directive.php
@@ -17,6 +17,7 @@ enum Directive
     case proxyRevalidate;
     case public;
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return match ($this) {
diff --git a/src/Header/CacheControl/MaxAge.php b/src/Header/CacheControl/MaxAge.php
index 13840e5c..8d52fe80 100644
--- a/src/Header/CacheControl/MaxAge.php
+++ b/src/Header/CacheControl/MaxAge.php
@@ -21,6 +21,7 @@ private function __construct(
      *
      * @param int<0, max> $age
      */
+    #[\NoDiscard]
     public static function of(int $age): self
     {
         return new self($age);
@@ -29,11 +30,13 @@ public static function of(int $age): self
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function age(): int
     {
         return $this->age;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return \sprintf(
diff --git a/src/Header/CacheControl/MaxStale.php b/src/Header/CacheControl/MaxStale.php
index 021a2e35..860a54ed 100644
--- a/src/Header/CacheControl/MaxStale.php
+++ b/src/Header/CacheControl/MaxStale.php
@@ -21,6 +21,7 @@ private function __construct(
      *
      * @param int<0, max> $age
      */
+    #[\NoDiscard]
     public static function of(int $age): self
     {
         return new self($age);
@@ -29,11 +30,13 @@ public static function of(int $age): self
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function age(): int
     {
         return $this->age;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return \sprintf(
diff --git a/src/Header/CacheControl/MinimumFresh.php b/src/Header/CacheControl/MinimumFresh.php
index 42bc3b3d..a6be4612 100644
--- a/src/Header/CacheControl/MinimumFresh.php
+++ b/src/Header/CacheControl/MinimumFresh.php
@@ -21,6 +21,7 @@ private function __construct(
      *
      * @param int<0, max> $age
      */
+    #[\NoDiscard]
     public static function of(int $age): self
     {
         return new self($age);
@@ -29,11 +30,13 @@ public static function of(int $age): self
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function age(): int
     {
         return $this->age;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return \sprintf(
diff --git a/src/Header/CacheControl/NoCache.php b/src/Header/CacheControl/NoCache.php
index 8936cb55..b0b9e9db 100644
--- a/src/Header/CacheControl/NoCache.php
+++ b/src/Header/CacheControl/NoCache.php
@@ -23,6 +23,7 @@ private function __construct(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $field): Maybe
     {
         if (!Str::of($field)->matches('~^\w*$~')) {
@@ -33,11 +34,13 @@ public static function maybe(string $field): Maybe
         return Maybe::just(new self($field));
     }
 
+    #[\NoDiscard]
     public function field(): string
     {
         return $this->field;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return \sprintf(
diff --git a/src/Header/CacheControl/PrivateCache.php b/src/Header/CacheControl/PrivateCache.php
index 3d1a125c..5bec07a9 100644
--- a/src/Header/CacheControl/PrivateCache.php
+++ b/src/Header/CacheControl/PrivateCache.php
@@ -23,6 +23,7 @@ private function __construct(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $field): Maybe
     {
         if (!Str::of($field)->matches('~^\w*$~')) {
@@ -33,11 +34,13 @@ public static function maybe(string $field): Maybe
         return Maybe::just(new self($field));
     }
 
+    #[\NoDiscard]
     public function field(): string
     {
         return $this->field;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return \sprintf(
diff --git a/src/Header/CacheControl/SharedMaxAge.php b/src/Header/CacheControl/SharedMaxAge.php
index d1320182..95eefab1 100644
--- a/src/Header/CacheControl/SharedMaxAge.php
+++ b/src/Header/CacheControl/SharedMaxAge.php
@@ -21,6 +21,7 @@ private function __construct(
      *
      * @param int<0, max> $age
      */
+    #[\NoDiscard]
     public static function of(int $age): self
     {
         return new self($age);
@@ -29,11 +30,13 @@ public static function of(int $age): self
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function age(): int
     {
         return $this->age;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return \sprintf(
diff --git a/src/Header/Content/Language.php b/src/Header/Content/Language.php
index 60eb17b9..34757197 100644
--- a/src/Header/Content/Language.php
+++ b/src/Header/Content/Language.php
@@ -23,6 +23,7 @@ private function __construct(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $language): Maybe
     {
         if (!Str::of($language)->matches('~^[a-zA-Z0-9]+(-[a-zA-Z0-9]+)*$~')) {
@@ -33,6 +34,7 @@ public static function maybe(string $language): Maybe
         return Maybe::just(new self($language));
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this->language;
diff --git a/src/Header/ContentEncoding.php b/src/Header/ContentEncoding.php
index 8adbf853..8053cf20 100644
--- a/src/Header/ContentEncoding.php
+++ b/src/Header/ContentEncoding.php
@@ -27,6 +27,7 @@ private function __construct(
      *
      * @throws DomainException
      */
+    #[\NoDiscard]
     public static function of(string $encoding): self
     {
         return self::maybe($encoding)->match(
@@ -40,6 +41,7 @@ public static function of(string $encoding): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $encoding): Maybe
     {
         return Maybe::just($encoding)
@@ -49,6 +51,7 @@ public static function maybe(string $encoding): Maybe
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/ContentLanguage.php b/src/Header/ContentLanguage.php
index 75cd28a7..42816259 100644
--- a/src/Header/ContentLanguage.php
+++ b/src/Header/ContentLanguage.php
@@ -26,12 +26,14 @@ private function __construct(
      * @no-named-arguments
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Language ...$languages): self
     {
         return new self(Sequence::of(...$languages));
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/ContentLength.php b/src/Header/ContentLength.php
index 131bc460..1e09474b 100644
--- a/src/Header/ContentLength.php
+++ b/src/Header/ContentLength.php
@@ -24,6 +24,7 @@ private function __construct(
      *
      * @param int<0, max> $length
      */
+    #[\NoDiscard]
     public static function of(int $length): self
     {
         return new self($length);
@@ -34,6 +35,7 @@ public static function of(int $length): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(int $length): Maybe
     {
         return Maybe::of(match (true) {
@@ -45,12 +47,14 @@ public static function maybe(int $length): Maybe
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function length(): int
     {
         return $this->length;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/ContentLocation.php b/src/Header/ContentLocation.php
index a4f65c59..fa17b954 100644
--- a/src/Header/ContentLocation.php
+++ b/src/Header/ContentLocation.php
@@ -19,17 +19,20 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Url $location): self
     {
         return new self($location);
     }
 
+    #[\NoDiscard]
     public function url(): Url
     {
         return $this->url;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/ContentRange.php b/src/Header/ContentRange.php
index a4a2b681..c1c9b6d1 100644
--- a/src/Header/ContentRange.php
+++ b/src/Header/ContentRange.php
@@ -33,6 +33,7 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(
         string $unit,
         int $firstPosition,
@@ -50,6 +51,7 @@ public static function of(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(
         string $unit,
         int $firstPosition,
@@ -76,6 +78,7 @@ public static function maybe(
         ));
     }
 
+    #[\NoDiscard]
     public function unit(): string
     {
         return $this->unit;
@@ -84,6 +87,7 @@ public function unit(): string
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function firstPosition(): int
     {
         return $this->firstPosition;
@@ -92,6 +96,7 @@ public function firstPosition(): int
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function lastPosition(): int
     {
         return $this->lastPosition;
@@ -100,12 +105,14 @@ public function lastPosition(): int
     /**
      * @return Maybe<int<0, max>>
      */
+    #[\NoDiscard]
     public function length(): Maybe
     {
         return Maybe::of($this->length);
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/ContentType.php b/src/Header/ContentType.php
index fef87233..dda090c3 100644
--- a/src/Header/ContentType.php
+++ b/src/Header/ContentType.php
@@ -20,17 +20,20 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(MediaType $content): self
     {
         return new self($content);
     }
 
+    #[\NoDiscard]
     public function content(): MediaType
     {
         return $this->content;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         $mediaType = MediaType::from(
diff --git a/src/Header/ContentType/Boundary.php b/src/Header/ContentType/Boundary.php
index d23db904..331f3321 100644
--- a/src/Header/ContentType/Boundary.php
+++ b/src/Header/ContentType/Boundary.php
@@ -32,6 +32,7 @@ private function __construct(
      *
      * @throws DomainException
      */
+    #[\NoDiscard]
     public static function of(string $value): self
     {
         return self::maybe($value)->match(
@@ -45,6 +46,7 @@ public static function of(string $value): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $value): Maybe
     {
         return Str::of($value)
@@ -55,16 +57,19 @@ public static function maybe(string $value): Maybe
             ->map(static fn($value) => new self($value->toString()));
     }
 
+    #[\NoDiscard]
     public static function uuid(): self
     {
         return self::of(Uuid::uuid4()->toString());
     }
 
+    #[\NoDiscard]
     public function value(): string
     {
         return $this->value;
     }
 
+    #[\NoDiscard]
     public function toHeader(): ContentType
     {
         return ContentType::of(MediaType\MediaType::from(
@@ -78,6 +83,7 @@ public function toHeader(): ContentType
         ));
     }
 
+    #[\NoDiscard]
     public function toParameter(): Parameter
     {
         return Parameter::of('boundary', $this->value);
diff --git a/src/Header/Cookie.php b/src/Header/Cookie.php
index f42e43d4..2bd2d548 100644
--- a/src/Header/Cookie.php
+++ b/src/Header/Cookie.php
@@ -26,6 +26,7 @@ private function __construct(
      * @no-named-arguments
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Parameter ...$parameters): self
     {
         /** @var Map<string, Parameter> */
@@ -44,12 +45,14 @@ public static function of(Parameter ...$parameters): self
     /**
      * @return Map<string, Parameter>
      */
+    #[\NoDiscard]
     public function parameters(): Map
     {
         return $this->parameters;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         $parameters = $this->parameters->values()->map(
diff --git a/src/Header/Date.php b/src/Header/Date.php
index f7664f95..c8efbbcc 100644
--- a/src/Header/Date.php
+++ b/src/Header/Date.php
@@ -25,17 +25,20 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Point $point): self
     {
         return new self($point);
     }
 
+    #[\NoDiscard]
     public function date(): Point
     {
         return $this->point;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/Expires.php b/src/Header/Expires.php
index 2dc62fd1..6ef558ea 100644
--- a/src/Header/Expires.php
+++ b/src/Header/Expires.php
@@ -25,17 +25,20 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Point $point): self
     {
         return new self($point);
     }
 
+    #[\NoDiscard]
     public function date(): Point
     {
         return $this->point;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/Host.php b/src/Header/Host.php
index 740216e1..a002ef6c 100644
--- a/src/Header/Host.php
+++ b/src/Header/Host.php
@@ -23,22 +23,26 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(UrlHost $host, Port $port): self
     {
         return new self($host, $port);
     }
 
+    #[\NoDiscard]
     public function host(): UrlHost
     {
         return $this->host;
     }
 
+    #[\NoDiscard]
     public function port(): Port
     {
         return $this->port;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/IfModifiedSince.php b/src/Header/IfModifiedSince.php
index 19cc8226..6ca7c84d 100644
--- a/src/Header/IfModifiedSince.php
+++ b/src/Header/IfModifiedSince.php
@@ -25,17 +25,20 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Point $point): self
     {
         return new self($point);
     }
 
+    #[\NoDiscard]
     public function date(): Point
     {
         return $this->point;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/IfUnmodifiedSince.php b/src/Header/IfUnmodifiedSince.php
index 3110fd8d..a61d03be 100644
--- a/src/Header/IfUnmodifiedSince.php
+++ b/src/Header/IfUnmodifiedSince.php
@@ -25,17 +25,20 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Point $point): self
     {
         return new self($point);
     }
 
+    #[\NoDiscard]
     public function date(): Point
     {
         return $this->point;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/LastModified.php b/src/Header/LastModified.php
index 81d49edd..526fe45d 100644
--- a/src/Header/LastModified.php
+++ b/src/Header/LastModified.php
@@ -25,17 +25,20 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Point $point): self
     {
         return new self($point);
     }
 
+    #[\NoDiscard]
     public function date(): Point
     {
         return $this->point;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/Link.php b/src/Header/Link.php
index 0de9a5ae..73ee6cf2 100644
--- a/src/Header/Link.php
+++ b/src/Header/Link.php
@@ -26,12 +26,14 @@ private function __construct(
      * @psalm-pure
      * @no-named-arguments
      */
+    #[\NoDiscard]
     public static function of(Relationship ...$relationships): self
     {
         return new self(Sequence::of(...$relationships));
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/Link/Relationship.php b/src/Header/Link/Relationship.php
index a5bda622..20cb84bf 100644
--- a/src/Header/Link/Relationship.php
+++ b/src/Header/Link/Relationship.php
@@ -31,6 +31,7 @@ private function __construct(
      *
      * @param ?non-empty-string $rel
      */
+    #[\NoDiscard]
     public static function of(
         Url $url,
         ?string $rel = null,
@@ -49,11 +50,13 @@ public static function of(
         return new self($url, $rel ?? 'related', $map);
     }
 
+    #[\NoDiscard]
     public function url(): Url
     {
         return $this->url;
     }
 
+    #[\NoDiscard]
     public function kind(): string
     {
         return $this->rel;
@@ -62,11 +65,13 @@ public function kind(): string
     /**
      * @return Map<string, Parameter>
      */
+    #[\NoDiscard]
     public function parameters(): Map
     {
         return $this->parameters;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         $parameters = $this->parameters->values()->map(
diff --git a/src/Header/Location.php b/src/Header/Location.php
index c4ff2d7f..e2cdc2b2 100644
--- a/src/Header/Location.php
+++ b/src/Header/Location.php
@@ -19,17 +19,20 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Url $location): self
     {
         return new self($location);
     }
 
+    #[\NoDiscard]
     public function url(): Url
     {
         return $this->location;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/Parameter.php b/src/Header/Parameter.php
index ce9adb6f..c5247c3c 100644
--- a/src/Header/Parameter.php
+++ b/src/Header/Parameter.php
@@ -31,21 +31,25 @@ private function __construct(string $name, string $value)
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(string $name, string $value): self
     {
         return new self($name, $value);
     }
 
+    #[\NoDiscard]
     public function name(): string
     {
         return $this->name;
     }
 
+    #[\NoDiscard]
     public function value(): string
     {
         return $this->value;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return \sprintf(
diff --git a/src/Header/Parameter/Quality.php b/src/Header/Parameter/Quality.php
index 33c6ae55..df022953 100644
--- a/src/Header/Parameter/Quality.php
+++ b/src/Header/Parameter/Quality.php
@@ -24,6 +24,7 @@ private function __construct(
      *
      * @param int<0, 100> $percent
      */
+    #[\NoDiscard]
     public static function of(int $percent): self
     {
         return new self($percent);
@@ -32,11 +33,13 @@ public static function of(int $percent): self
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function max(): self
     {
         return new self(100);
     }
 
+    #[\NoDiscard]
     public function toParameter(): Parameter
     {
         $value = Str::of(\sprintf(
diff --git a/src/Header/Range.php b/src/Header/Range.php
index 14041dfd..a7a5b500 100644
--- a/src/Header/Range.php
+++ b/src/Header/Range.php
@@ -33,6 +33,7 @@ private function __construct(
      *
      * @throws DomainException
      */
+    #[\NoDiscard]
     public static function of(
         string $unit,
         int $firstPosition,
@@ -49,6 +50,7 @@ public static function of(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(
         string $unit,
         int $firstPosition,
@@ -67,6 +69,7 @@ public static function maybe(
         return Maybe::just(new self($unit, $firstPosition, $lastPosition));
     }
 
+    #[\NoDiscard]
     public function unit(): string
     {
         return $this->unit;
@@ -75,6 +78,7 @@ public function unit(): string
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function firstPosition(): int
     {
         return $this->firstPosition;
@@ -83,12 +87,14 @@ public function firstPosition(): int
     /**
      * @return int<0, max>
      */
+    #[\NoDiscard]
     public function lastPosition(): int
     {
         return $this->lastPosition;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/Referrer.php b/src/Header/Referrer.php
index 207f0259..49037ced 100644
--- a/src/Header/Referrer.php
+++ b/src/Header/Referrer.php
@@ -19,17 +19,20 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Url $referrer): self
     {
         return new self($referrer);
     }
 
+    #[\NoDiscard]
     public function referrer(): Url
     {
         return $this->referrer;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/SetCookie.php b/src/Header/SetCookie.php
index fd7397f1..6fdc62bc 100644
--- a/src/Header/SetCookie.php
+++ b/src/Header/SetCookie.php
@@ -36,6 +36,7 @@ private function __construct(
      * @no-named-arguments
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(
         string $name,
         string $value,
@@ -48,6 +49,7 @@ public static function of(
         );
     }
 
+    #[\NoDiscard]
     public function and(self $cookie): self
     {
         return new self(
@@ -57,11 +59,13 @@ public function and(self $cookie): self
         );
     }
 
+    #[\NoDiscard]
     public function name(): string
     {
         return $this->value->name();
     }
 
+    #[\NoDiscard]
     public function value(): string
     {
         return $this->value->value();
@@ -70,6 +74,7 @@ public function value(): string
     /**
      * @return Sequence<Directive|Domain|Expires|MaxAge|Path>
      */
+    #[\NoDiscard]
     public function parameters(): Sequence
     {
         return $this->parameters;
@@ -78,12 +83,14 @@ public function parameters(): Sequence
     /**
      * @return Sequence<self>
      */
+    #[\NoDiscard]
     public function cookies(): Sequence
     {
         return Sequence::of($this)->append($this->others);
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/SetCookie/Directive.php b/src/Header/SetCookie/Directive.php
index 84fa5e2f..a0cfb86b 100644
--- a/src/Header/SetCookie/Directive.php
+++ b/src/Header/SetCookie/Directive.php
@@ -15,6 +15,7 @@ enum Directive
     case secure;
     case httpOnly;
 
+    #[\NoDiscard]
     public function toParameter(): Parameter
     {
         return match ($this) {
diff --git a/src/Header/SetCookie/Domain.php b/src/Header/SetCookie/Domain.php
index 8516a9cb..ea1cd2af 100644
--- a/src/Header/SetCookie/Domain.php
+++ b/src/Header/SetCookie/Domain.php
@@ -19,16 +19,19 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Host $host): self
     {
         return new self($host);
     }
 
+    #[\NoDiscard]
     public function host(): Host
     {
         return $this->host;
     }
 
+    #[\NoDiscard]
     public function toParameter(): Parameter
     {
         return Parameter::of('Domain', $this->host->toString());
diff --git a/src/Header/SetCookie/Expires.php b/src/Header/SetCookie/Expires.php
index 93d67878..2840577b 100644
--- a/src/Header/SetCookie/Expires.php
+++ b/src/Header/SetCookie/Expires.php
@@ -25,16 +25,19 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function at(Point $date): self
     {
         return new self($date->changeOffset(Offset::utc()));
     }
 
+    #[\NoDiscard]
     public function date(): Point
     {
         return $this->date;
     }
 
+    #[\NoDiscard]
     public function toParameter(): Parameter
     {
         return Parameter::of(
diff --git a/src/Header/SetCookie/MaxAge.php b/src/Header/SetCookie/MaxAge.php
index bf1af28f..5b11fc0a 100644
--- a/src/Header/SetCookie/MaxAge.php
+++ b/src/Header/SetCookie/MaxAge.php
@@ -23,6 +23,7 @@ private function __construct(
      *
      * @param int<1, max> $age
      */
+    #[\NoDiscard]
     public static function of(int $age): self
     {
         return new self($age);
@@ -31,11 +32,13 @@ public static function of(int $age): self
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function expire(): self
     {
         return new self(null);
     }
 
+    #[\NoDiscard]
     public function toInt(): int
     {
         return match ($this->age) {
@@ -44,6 +47,7 @@ public function toInt(): int
         };
     }
 
+    #[\NoDiscard]
     public function toParameter(): Parameter
     {
         return Parameter::of('Max-Age', (string) $this->toInt());
diff --git a/src/Header/SetCookie/Path.php b/src/Header/SetCookie/Path.php
index b5eabb93..4f198d83 100644
--- a/src/Header/SetCookie/Path.php
+++ b/src/Header/SetCookie/Path.php
@@ -19,16 +19,19 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(UrlPath $path): self
     {
         return new self($path);
     }
 
+    #[\NoDiscard]
     public function path(): UrlPath
     {
         return $this->path;
     }
 
+    #[\NoDiscard]
     public function toParameter(): Parameter
     {
         return Parameter::of('Path', $this->path->toString());
diff --git a/src/Header/Value.php b/src/Header/Value.php
index 13f98323..d46ce5bf 100644
--- a/src/Header/Value.php
+++ b/src/Header/Value.php
@@ -16,11 +16,13 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(string $value): self
     {
         return new self($value);
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this->value;
diff --git a/src/Header/WWWAuthenticate.php b/src/Header/WWWAuthenticate.php
index c688cd2f..79fa82f0 100644
--- a/src/Header/WWWAuthenticate.php
+++ b/src/Header/WWWAuthenticate.php
@@ -26,12 +26,14 @@ private function __construct(
      * @psalm-pure
      * @no-named-arguments
      */
+    #[\NoDiscard]
     public static function of(Challenge ...$challenges): self
     {
         return new self(Sequence::of(...$challenges));
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function normalize(): Header
     {
         return Header::of(
diff --git a/src/Header/WWWAuthenticate/Challenge.php b/src/Header/WWWAuthenticate/Challenge.php
index 991dd59e..ced0bb89 100644
--- a/src/Header/WWWAuthenticate/Challenge.php
+++ b/src/Header/WWWAuthenticate/Challenge.php
@@ -25,6 +25,7 @@ private function __construct(
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $scheme, string $realm): Maybe
     {
         $scheme = Str::of($scheme);
@@ -37,16 +38,19 @@ public static function maybe(string $scheme, string $realm): Maybe
         return Maybe::just(new self($scheme->toString(), $realm));
     }
 
+    #[\NoDiscard]
     public function scheme(): string
     {
         return $this->scheme;
     }
 
+    #[\NoDiscard]
     public function realm(): string
     {
         return $this->realm;
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return Str::of($this->scheme)
diff --git a/src/Headers.php b/src/Headers.php
index fe202991..65c8424c 100644
--- a/src/Headers.php
+++ b/src/Headers.php
@@ -25,6 +25,7 @@ private function __construct(
     ) {
     }
 
+    #[\NoDiscard]
     public function __invoke(Header|Header\Custom $header): self
     {
         $name = self::normalize(match (true) {
@@ -39,6 +40,7 @@ public function __invoke(Header|Header\Custom $header): self
      * @no-named-arguments
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(Header|Header\Custom ...$headers): self
     {
         return Sequence::of(...$headers)->reduce(
@@ -52,6 +54,7 @@ public static function of(Header|Header\Custom ...$headers): self
      *
      * @return Maybe<Header>
      */
+    #[\NoDiscard]
     public function get(string $name): Maybe
     {
         $normalized = self::normalize($name);
@@ -72,6 +75,7 @@ public function get(string $name): Maybe
      *
      * @return Maybe<T>
      */
+    #[\NoDiscard]
     public function find(string $type): Maybe
     {
         return $this
@@ -86,6 +90,7 @@ public function find(string $type): Maybe
      *
      * @param string $name Case insensitive
      */
+    #[\NoDiscard]
     public function contains(string $name): bool
     {
         return $this->get($name)->match(
@@ -97,6 +102,7 @@ public function contains(string $name): bool
     /**
      * @param callable(Header): bool $filter
      */
+    #[\NoDiscard]
     public function filter(callable $filter): self
     {
         return new self($this->headers->filter(static fn($_, $header) => match (true) {
@@ -108,6 +114,7 @@ public function filter(callable $filter): self
     /**
      * @param callable(Header|Header\Custom): void $function
      */
+    #[\NoDiscard]
     public function foreach(callable $function): SideEffect
     {
         return $this->headers->values()->foreach($function);
@@ -121,12 +128,14 @@ public function foreach(callable $function): SideEffect
      *
      * @return R
      */
+    #[\NoDiscard]
     public function reduce($carry, callable $reducer)
     {
         return $this->all()->reduce($carry, $reducer);
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function count(): int
     {
         return $this->headers->size();
@@ -135,6 +144,7 @@ public function count(): int
     /**
      * @return Sequence<Header>
      */
+    #[\NoDiscard]
     public function all(): Sequence
     {
         return $this->headers->values()->map(static fn($header) => match (true) {
diff --git a/src/Method.php b/src/Method.php
index 6a2d66d0..9746585b 100644
--- a/src/Method.php
+++ b/src/Method.php
@@ -26,6 +26,7 @@ enum Method
      * @psalm-pure
      * @throws \UnhandledMatchError
      */
+    #[\NoDiscard]
     public static function of(string $method): self
     {
         return match ($method) {
@@ -48,6 +49,7 @@ public static function of(string $method): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(string $method): Maybe
     {
         try {
@@ -58,6 +60,7 @@ public static function maybe(string $method): Maybe
         }
     }
 
+    #[\NoDiscard]
     public function safe(): bool
     {
         return match ($this) {
@@ -75,6 +78,7 @@ public function safe(): bool
         };
     }
 
+    #[\NoDiscard]
     public function idempotent(): bool
     {
         return match ($this) {
@@ -92,6 +96,7 @@ public function idempotent(): bool
         };
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return match ($this) {
diff --git a/src/ProtocolVersion.php b/src/ProtocolVersion.php
index 3e6cad02..17caa18e 100644
--- a/src/ProtocolVersion.php
+++ b/src/ProtocolVersion.php
@@ -19,6 +19,7 @@ enum ProtocolVersion
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(int $major, int $minor): Maybe
     {
         /** @var Maybe<self> */
@@ -33,6 +34,7 @@ public static function maybe(int $major, int $minor): Maybe
     /**
      * @return non-empty-string
      */
+    #[\NoDiscard]
     public function toString(): string
     {
         return match ($this) {
diff --git a/src/Request.php b/src/Request.php
index 877e5010..6ea4e0f6 100644
--- a/src/Request.php
+++ b/src/Request.php
@@ -23,6 +23,7 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(
         Url $url,
         Method $method,
@@ -39,26 +40,31 @@ public static function of(
         );
     }
 
+    #[\NoDiscard]
     public function url(): Url
     {
         return $this->url;
     }
 
+    #[\NoDiscard]
     public function method(): Method
     {
         return $this->method;
     }
 
+    #[\NoDiscard]
     public function protocolVersion(): ProtocolVersion
     {
         return $this->protocolVersion;
     }
 
+    #[\NoDiscard]
     public function headers(): Headers
     {
         return $this->headers;
     }
 
+    #[\NoDiscard]
     public function body(): Content
     {
         return $this->body;
diff --git a/src/Request/Stringable.php b/src/Request/Stringable.php
index 520c66b7..04592e95 100644
--- a/src/Request/Stringable.php
+++ b/src/Request/Stringable.php
@@ -19,6 +19,7 @@ private function __construct()
     {
     }
 
+    #[\NoDiscard]
     public function __invoke(Request $request): Content
     {
         $status = Str::of("%s %s HTTP/%s\n")->sprintf(
@@ -48,6 +49,7 @@ public function __invoke(Request $request): Content
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function new(): self
     {
         return new self;
diff --git a/src/Response.php b/src/Response.php
index 432d6c67..5d461f0b 100644
--- a/src/Response.php
+++ b/src/Response.php
@@ -22,6 +22,7 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(
         StatusCode $statusCode,
         ProtocolVersion $protocolVersion,
@@ -36,21 +37,25 @@ public static function of(
         );
     }
 
+    #[\NoDiscard]
     public function protocolVersion(): ProtocolVersion
     {
         return $this->protocolVersion;
     }
 
+    #[\NoDiscard]
     public function headers(): Headers
     {
         return $this->headers;
     }
 
+    #[\NoDiscard]
     public function body(): Content
     {
         return $this->body;
     }
 
+    #[\NoDiscard]
     public function statusCode(): StatusCode
     {
         return $this->statusCode;
diff --git a/src/Response/Sender.php b/src/Response/Sender.php
index ded01009..a8f6dc0d 100644
--- a/src/Response/Sender.php
+++ b/src/Response/Sender.php
@@ -14,5 +14,6 @@ interface Sender
     /**
      * @return Attempt<SideEffect>
      */
+    #[\NoDiscard]
     public function __invoke(Response $response): Attempt;
 }
diff --git a/src/Response/Sender/Native.php b/src/Response/Sender/Native.php
index 77404969..16a5f63d 100644
--- a/src/Response/Sender/Native.php
+++ b/src/Response/Sender/Native.php
@@ -82,6 +82,7 @@ public function __invoke(Response $response): Attempt
         return Attempt::result(SideEffect::identity());
     }
 
+    #[\NoDiscard]
     public static function of(Clock $clock): self
     {
         return new self($clock);
diff --git a/src/Response/StatusCode.php b/src/Response/StatusCode.php
index 42959778..2395dc2b 100644
--- a/src/Response/StatusCode.php
+++ b/src/Response/StatusCode.php
@@ -90,6 +90,7 @@ enum StatusCode: int
      *
      * @throws \UnhandledMatchError
      */
+    #[\NoDiscard]
     public static function of(int $code): self
     {
         return match ($code) {
@@ -175,6 +176,7 @@ public static function of(int $code): self
      *
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public static function maybe(int $code): Maybe
     {
         try {
@@ -185,6 +187,7 @@ public static function maybe(int $code): Maybe
         }
     }
 
+    #[\NoDiscard]
     public function toInt(): int
     {
         return $this->value;
@@ -193,11 +196,13 @@ public function toInt(): int
     /**
      * @return non-empty-string
      */
+    #[\NoDiscard]
     public function toString(): string
     {
         return (string) $this->toInt();
     }
 
+    #[\NoDiscard]
     public function range(): StatusCode\Range
     {
         return match ($this) {
@@ -278,26 +283,31 @@ public function range(): StatusCode\Range
         };
     }
 
+    #[\NoDiscard]
     public function informational(): bool
     {
         return $this->range() === StatusCode\Range::informational;
     }
 
+    #[\NoDiscard]
     public function successful(): bool
     {
         return $this->range() === StatusCode\Range::successful;
     }
 
+    #[\NoDiscard]
     public function redirection(): bool
     {
         return $this->range() === StatusCode\Range::redirection;
     }
 
+    #[\NoDiscard]
     public function clientError(): bool
     {
         return $this->range() === StatusCode\Range::clientError;
     }
 
+    #[\NoDiscard]
     public function serverError(): bool
     {
         return $this->range() === StatusCode\Range::serverError;
@@ -306,6 +316,7 @@ public function serverError(): bool
     /**
      * @return non-empty-string
      */
+    #[\NoDiscard]
     public function reasonPhrase(): string
     {
         return match ($this) {
diff --git a/src/Response/Stringable.php b/src/Response/Stringable.php
index 8c09f281..89a3b2a4 100644
--- a/src/Response/Stringable.php
+++ b/src/Response/Stringable.php
@@ -19,6 +19,7 @@ private function __construct()
     {
     }
 
+    #[\NoDiscard]
     public function __invoke(Response $response): Content
     {
         $status = Str::of("HTTP/%s %s %s\n")->sprintf(
@@ -48,6 +49,7 @@ public function __invoke(Response $response): Content
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function new(): self
     {
         return new self;
diff --git a/src/ServerRequest.php b/src/ServerRequest.php
index 5d3e187c..2a0beb1a 100644
--- a/src/ServerRequest.php
+++ b/src/ServerRequest.php
@@ -35,6 +35,7 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(
         Url $url,
         Method $method,
@@ -61,51 +62,61 @@ public static function of(
         );
     }
 
+    #[\NoDiscard]
     public function protocolVersion(): ProtocolVersion
     {
         return $this->protocolVersion;
     }
 
+    #[\NoDiscard]
     public function headers(): Headers
     {
         return $this->headers;
     }
 
+    #[\NoDiscard]
     public function body(): Content
     {
         return $this->body;
     }
 
+    #[\NoDiscard]
     public function url(): Url
     {
         return $this->url;
     }
 
+    #[\NoDiscard]
     public function method(): Method
     {
         return $this->method;
     }
 
+    #[\NoDiscard]
     public function environment(): Environment
     {
         return $this->environment;
     }
 
+    #[\NoDiscard]
     public function cookies(): Cookies
     {
         return $this->cookies;
     }
 
+    #[\NoDiscard]
     public function query(): Query
     {
         return $this->query;
     }
 
+    #[\NoDiscard]
     public function form(): Form
     {
         return $this->form;
     }
 
+    #[\NoDiscard]
     public function files(): Files
     {
         return $this->files;
diff --git a/src/ServerRequest/Cookies.php b/src/ServerRequest/Cookies.php
index 9a44fc3d..639983fa 100644
--- a/src/ServerRequest/Cookies.php
+++ b/src/ServerRequest/Cookies.php
@@ -33,6 +33,7 @@ private function __construct(?Map $cookies = null)
      *
      * @param Map<string, string>|null $cookies
      */
+    #[\NoDiscard]
     public static function of(?Map $cookies = null): self
     {
         return new self($cookies);
@@ -41,11 +42,13 @@ public static function of(?Map $cookies = null): self
     /**
      * @return Maybe<string>
      */
+    #[\NoDiscard]
     public function get(string $name): Maybe
     {
         return $this->cookies->get($name);
     }
 
+    #[\NoDiscard]
     public function contains(string $name): bool
     {
         return $this->cookies->contains($name);
@@ -54,6 +57,7 @@ public function contains(string $name): bool
     /**
      * @param callable(string, string): void $function
      */
+    #[\NoDiscard]
     public function foreach(callable $function): SideEffect
     {
         return $this->cookies->foreach($function);
@@ -67,12 +71,14 @@ public function foreach(callable $function): SideEffect
      *
      * @return R
      */
+    #[\NoDiscard]
     public function reduce($carry, callable $reducer)
     {
         return $this->cookies->reduce($carry, $reducer);
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function count(): int
     {
         return $this->cookies->size();
diff --git a/src/ServerRequest/Environment.php b/src/ServerRequest/Environment.php
index 2c803a4e..2c3c87a9 100644
--- a/src/ServerRequest/Environment.php
+++ b/src/ServerRequest/Environment.php
@@ -33,6 +33,7 @@ private function __construct(?Map $variables = null)
      *
      * @param Map<string, string>|null $variables
      */
+    #[\NoDiscard]
     public static function of(?Map $variables = null): self
     {
         return new self($variables);
@@ -41,11 +42,13 @@ public static function of(?Map $variables = null): self
     /**
      * @return Maybe<string>
      */
+    #[\NoDiscard]
     public function get(string $name): Maybe
     {
         return $this->variables->get($name);
     }
 
+    #[\NoDiscard]
     public function contains(string $name): bool
     {
         return $this->variables->contains($name);
@@ -54,6 +57,7 @@ public function contains(string $name): bool
     /**
      * @param callable(string, string): void $function
      */
+    #[\NoDiscard]
     public function foreach(callable $function): SideEffect
     {
         return $this->variables->foreach($function);
@@ -67,12 +71,14 @@ public function foreach(callable $function): SideEffect
      *
      * @return R
      */
+    #[\NoDiscard]
     public function reduce($carry, callable $reducer)
     {
         return $this->variables->reduce($carry, $reducer);
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function count(): int
     {
         return $this->variables->size();
diff --git a/src/ServerRequest/Files.php b/src/ServerRequest/Files.php
index 284463f1..42379d06 100644
--- a/src/ServerRequest/Files.php
+++ b/src/ServerRequest/Files.php
@@ -23,6 +23,7 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(array $files): self
     {
         return new self($files);
@@ -33,6 +34,7 @@ public static function of(array $files): self
      *
      * @return Either<Status, File>
      */
+    #[\NoDiscard]
     public function get(int|string $key): Either
     {
         if (!\array_key_exists($key, $this->files)) {
@@ -62,6 +64,7 @@ public function get(int|string $key): Either
     /**
      * @param non-empty-string $name
      */
+    #[\NoDiscard]
     public function under(string $name): self
     {
         /** @var mixed */
@@ -81,6 +84,7 @@ public function under(string $name): self
      *
      * @return Sequence<File>
      */
+    #[\NoDiscard]
     public function list(string $name): Sequence
     {
         /** @var mixed */
diff --git a/src/ServerRequest/Form.php b/src/ServerRequest/Form.php
index e0c0fc71..f07009a1 100644
--- a/src/ServerRequest/Form.php
+++ b/src/ServerRequest/Form.php
@@ -18,6 +18,7 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(array $data): self
     {
         return new self($data);
@@ -26,6 +27,7 @@ public static function of(array $data): self
     /**
      * @return Maybe<string|array>
      */
+    #[\NoDiscard]
     public function get(int|string $key): Maybe
     {
         if (!\array_key_exists($key, $this->data)) {
@@ -40,6 +42,7 @@ public function get(int|string $key): Maybe
     /**
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public function list(int|string $key): Maybe
     {
         /** @psalm-suppress InvalidArgument Psalm doesn't understand the filters */
@@ -53,6 +56,7 @@ public function list(int|string $key): Maybe
     /**
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public function dictionary(int|string $key): Maybe
     {
         /** @psalm-suppress InvalidArgument Psalm doesn't understand the filters */
@@ -63,6 +67,7 @@ public function dictionary(int|string $key): Maybe
             ->map(static fn(array $data) => new self($data));
     }
 
+    #[\NoDiscard]
     public function contains(int|string $key): bool
     {
         return $this->get($key)->match(
@@ -71,12 +76,14 @@ public function contains(int|string $key): bool
         );
     }
 
+    #[\NoDiscard]
     public function data(): array
     {
         return $this->data;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function count(): int
     {
         return \count($this->data);
diff --git a/src/ServerRequest/Query.php b/src/ServerRequest/Query.php
index daf08563..b03795d6 100644
--- a/src/ServerRequest/Query.php
+++ b/src/ServerRequest/Query.php
@@ -19,6 +19,7 @@ private function __construct(
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function of(array $data): self
     {
         return new self($data);
@@ -27,6 +28,7 @@ public static function of(array $data): self
     /**
      * @return Maybe<string|array>
      */
+    #[\NoDiscard]
     public function get(int|string $key): Maybe
     {
         if (!\array_key_exists($key, $this->data)) {
@@ -41,6 +43,7 @@ public function get(int|string $key): Maybe
     /**
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public function list(int|string $key): Maybe
     {
         /** @psalm-suppress InvalidArgument Psalm doesn't understand the filters */
@@ -54,6 +57,7 @@ public function list(int|string $key): Maybe
     /**
      * @return Maybe<self>
      */
+    #[\NoDiscard]
     public function dictionary(int|string $key): Maybe
     {
         /** @psalm-suppress InvalidArgument Psalm doesn't understand the filters */
@@ -64,6 +68,7 @@ public function dictionary(int|string $key): Maybe
             ->map(static fn(array $data) => new self($data));
     }
 
+    #[\NoDiscard]
     public function contains(int|string $key): bool
     {
         return $this->get($key)->match(
@@ -72,12 +77,14 @@ public function contains(int|string $key): bool
         );
     }
 
+    #[\NoDiscard]
     public function data(): array
     {
         return $this->data;
     }
 
     #[\Override]
+    #[\NoDiscard]
     public function count(): int
     {
         return \count($this->data);
diff --git a/src/ServerRequest/Stringable.php b/src/ServerRequest/Stringable.php
index ded46eda..a1706281 100644
--- a/src/ServerRequest/Stringable.php
+++ b/src/ServerRequest/Stringable.php
@@ -19,6 +19,7 @@ private function __construct()
     {
     }
 
+    #[\NoDiscard]
     public function __invoke(ServerRequest $request): Content
     {
         $status = Str::of("%s %s%s HTTP/%s\n")->sprintf(
@@ -48,6 +49,7 @@ public function __invoke(ServerRequest $request): Content
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function new(): self
     {
         return new self;
diff --git a/src/Time/Format/Http.php b/src/Time/Format/Http.php
index 506a29c8..050cdea7 100644
--- a/src/Time/Format/Http.php
+++ b/src/Time/Format/Http.php
@@ -10,6 +10,7 @@ final class Http
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function new(): Format
     {
         return Format::of('D, d M Y H:i:s \G\M\T');
diff --git a/tests/Header/ContentType/BoundaryTest.php b/tests/Header/ContentType/BoundaryTest.php
index ed817b11..ee00436c 100644
--- a/tests/Header/ContentType/BoundaryTest.php
+++ b/tests/Header/ContentType/BoundaryTest.php
@@ -34,7 +34,7 @@ public function testThrowWhenRandomString()
             ))
             ->then(function($random) {
                 try {
-                    Boundary::of($random);
+                    $_ = Boundary::of($random);
                     $this->fail('it should throw');
                 } catch (DomainException $e) {
                     $this->assertSame($random, $e->getMessage());
diff --git a/tests/MethodTest.php b/tests/MethodTest.php
index cf328bea..03f5ce42 100644
--- a/tests/MethodTest.php
+++ b/tests/MethodTest.php
@@ -30,7 +30,7 @@ public function testThrowWhenInvalidMethod()
     {
         $this->expectException(\UnhandledMatchError::class);
 
-        Method::of('get');
+        $_ = Method::of('get');
     }
 
     public function methods(): Set
diff --git a/tests/Response/StatusCodeTest.php b/tests/Response/StatusCodeTest.php
index 08ea0b93..8b327596 100644
--- a/tests/Response/StatusCodeTest.php
+++ b/tests/Response/StatusCodeTest.php
@@ -24,7 +24,7 @@ public function testInterface()
     public function testThrowWhenInvalidStatusCode()
     {
         try {
-            StatusCode::of(42); //sadly
+            $_ = StatusCode::of(42); //sadly
 
             $this->fail('it should throw');
         } catch (\Throwable $e) {