diff --git a/src/DispatchContext.php b/src/DispatchContext.php
index b97a2f5..4b5931b 100644
--- a/src/DispatchContext.php
+++ b/src/DispatchContext.php
@@ -18,6 +18,8 @@
 
 use function in_array;
 use function is_a;
+use function preg_quote;
+use function preg_replace;
 use function rawurldecode;
 use function rtrim;
 use function set_error_handler;
@@ -29,14 +31,12 @@
 final class DispatchContext implements ContainerInterface
 {
     /** @var array<int, mixed> */
-    public array $params = [];
+    public private(set) array $params = [];
 
-    public AbstractRoute|null $route = null;
+    public private(set) AbstractRoute|null $route = null;
 
     /** @var array<string, string> Headers to apply only when the response does not already have them */
-    public array $defaultResponseHeaders = [];
-
-    private RoutinePipeline|null $routinePipeline = null;
+    public private(set) array $defaultResponseHeaders = [];
 
     private Responder|null $responder = null;
 
@@ -49,21 +49,32 @@ final class DispatchContext implements ContainerInterface
 
     private bool $hasStatusOverride = false;
 
-    private string $effectiveMethod = '';
-
-    private string $effectivePath = '';
+    private string $effectiveMethod;
 
-    /** @var array<int, AbstractRoute> */
-    private array $handlers = [];
+    private string $effectivePath;
 
     private Resolver|null $resolver = null;
 
+    /** @param array<int, AbstractRoute> $handlers */
     public function __construct(
-        public ServerRequestInterface $request,
-        public ResponseFactoryInterface&StreamFactoryInterface $factory,
+        public private(set) ServerRequestInterface $request,
+        public private(set) ResponseFactoryInterface&StreamFactoryInterface $factory,
+        private RoutinePipeline $routinePipeline = new RoutinePipeline(),
+        private array $handlers = [],
+        string $basePath = '',
     ) {
-        $this->effectivePath = rtrim(rawurldecode($request->getUri()->getPath()), ' /');
+        $path = rtrim(rawurldecode($request->getUri()->getPath()), ' /');
+        if ($basePath !== '') {
+            $path = preg_replace(
+                '#^' . preg_quote($basePath, '#') . '#',
+                '',
+                $path,
+            ) ?? $path;
+        }
+
+        $this->effectivePath = $path;
         $this->effectiveMethod = strtoupper($request->getMethod());
+        $this->resetHandlerState();
     }
 
     public function method(): string
@@ -76,11 +87,6 @@ public function path(): string
         return $this->effectivePath;
     }
 
-    public function setPath(string $path): void
-    {
-        $this->effectivePath = $path;
-    }
-
     public function hasPreparedResponse(): bool
     {
         return $this->hasPreparedResponse;
@@ -125,6 +131,13 @@ public function prepareResponse(int $status, array $headers = []): void
         }
     }
 
+    /** @param array<int, mixed> $params */
+    public function configureRoute(AbstractRoute $route, array $params = []): void
+    {
+        $this->route = $route;
+        $this->params = $params;
+    }
+
     /** Generates the PSR-7 response from the current route */
     public function response(): ResponseInterface|null
     {
@@ -146,7 +159,7 @@ public function response(): ResponseInterface|null
         $previousErrorHandler = $isHandler ? null : $this->installErrorHandler();
 
         try {
-            $preRoutineResult = $this->routinePipeline()->processBy($this, $route);
+            $preRoutineResult = $this->routinePipeline->processBy($this, $route);
 
             if ($preRoutineResult instanceof AbstractRoute) {
                 return $this->forward($preRoutineResult);
@@ -166,7 +179,7 @@ public function response(): ResponseInterface|null
                 return $this->forward($rawResult);
             }
 
-            $processedResult = $this->routinePipeline()->processThrough($this, $route, $rawResult);
+            $processedResult = $this->routinePipeline->processThrough($this, $route, $rawResult);
 
             if (!$isHandler) {
                 $errorResponse = $this->forwardCollectedErrors();
@@ -192,27 +205,21 @@ public function response(): ResponseInterface|null
         }
     }
 
-    public function forward(AbstractRoute $route): ResponseInterface|null
+    public function withRequest(ServerRequestInterface $request): void
     {
-        $this->route = $route;
-
-        return $this->response();
+        $this->request = $request;
     }
 
-    public function setRoutinePipeline(RoutinePipeline $routinePipeline): void
+    public function setResponder(Responder $responder): void
     {
-        $this->routinePipeline = $routinePipeline;
+        $this->responder = $responder;
     }
 
-    /** @param array<int, AbstractRoute> $handlers */
-    public function setHandlers(array $handlers): void
+    public function forward(AbstractRoute $route): ResponseInterface|null
     {
-        $this->handlers = $handlers;
-    }
+        $this->route = $route;
 
-    public function setResponder(Responder $responder): void
-    {
-        $this->responder = $responder;
+        return $this->response();
     }
 
     public function resolver(): Resolver
@@ -239,7 +246,26 @@ public function get(string $id): mixed
         throw new NotFoundException(sprintf('No entry found for "%s"', $id));
     }
 
-    /** @return callable|null The previous error handler, or null if no ErrorHandler is registered */
+    private function resetHandlerState(): void
+    {
+        foreach ($this->handlers as $handler) {
+            if ($handler instanceof ErrorHandler) {
+                $handler->errors = [];
+            } elseif ($handler instanceof ExceptionHandler) {
+                $handler->exception = null;
+            }
+        }
+    }
+
+    /**
+     * Safe only when requests are guaranteed not to overlap within the same PHP process
+     * (for example: PHP-FPM, Swoole workers, FrankenPHP workers, or ReactPHP when
+     * request handling/dispatch is strictly serialized). Not safe for coroutine- or
+     * event-loop-concurrent request handling within a single PHP process, since
+     * set_error_handler is global state.
+     *
+     * @return callable|null The previous error handler, or null if no ErrorHandler is registered
+     */
     private function installErrorHandler(): callable|null
     {
         foreach ($this->handlers as $handler) {
@@ -303,7 +329,7 @@ private function forwardToStatusRoute(ResponseInterface $preparedResponse): Resp
 
                 // Run routine negotiation (e.g. Accept) before forwarding,
                 // since the normal route-selection phase was skipped
-                $this->routinePipeline()->matches($this, $handler, $this->params);
+                $this->routinePipeline->matches($this, $handler, $this->params);
 
                 $result = $this->forward($handler);
 
@@ -327,27 +353,14 @@ private function finalizeResponse(mixed $response): ResponseInterface
         );
     }
 
-    private function routinePipeline(): RoutinePipeline
-    {
-        return $this->routinePipeline ??= new RoutinePipeline();
-    }
-
     private function responder(): Responder
     {
-        if ($this->responder !== null) {
-            return $this->responder;
-        }
-
-        return $this->responder = new Responder($this->factory);
+        return $this->responder ??= new Responder($this->factory);
     }
 
     private function ensureResponseDraft(): ResponseInterface
     {
-        if ($this->responseDraft !== null) {
-            return $this->responseDraft;
-        }
-
-        return $this->responseDraft = $this->factory->createResponse();
+        return $this->responseDraft ??= $this->factory->createResponse();
     }
 
     public function __toString(): string
diff --git a/src/DispatchEngine.php b/src/DispatchEngine.php
index bedb724..cd58491 100644
--- a/src/DispatchEngine.php
+++ b/src/DispatchEngine.php
@@ -4,7 +4,6 @@
 
 namespace Respect\Rest;
 
-use Closure;
 use Psr\Http\Message\ResponseFactoryInterface;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
@@ -19,28 +18,32 @@
 use function count;
 use function implode;
 use function iterator_to_array;
-use function preg_quote;
-use function preg_replace;
 use function stripos;
 
 final class DispatchEngine implements RequestHandlerInterface
 {
     private RoutinePipeline $routinePipeline;
 
-    /** @param (Closure(DispatchContext): void)|null $onContextReady */
     public function __construct(
         private RouteProvider $routeProvider,
         private ResponseFactoryInterface&StreamFactoryInterface $factory,
-        private Closure|null $onContextReady = null,
     ) {
         $this->routinePipeline = new RoutinePipeline();
     }
 
+    public function routinePipeline(): RoutinePipeline
+    {
+        return $this->routinePipeline;
+    }
+
     public function dispatch(ServerRequestInterface $serverRequest): DispatchContext
     {
         $context = new DispatchContext(
             $serverRequest,
             $this->factory,
+            $this->routinePipeline,
+            $this->routeProvider->getHandlers(),
+            $this->routeProvider->getBasePath(),
         );
 
         return $this->dispatchContext($context);
@@ -55,13 +58,6 @@ public function handle(ServerRequestInterface $request): ResponseInterface
 
     public function dispatchContext(DispatchContext $context): DispatchContext
     {
-        if ($this->onContextReady !== null) {
-            ($this->onContextReady)($context);
-        }
-
-        $context->setRoutinePipeline($this->routinePipeline);
-        $context->setHandlers($this->routeProvider->getHandlers());
-
         if (!$this->isRoutelessDispatch($context) && $context->route === null) {
             $this->routeDispatch($context);
         }
@@ -120,8 +116,6 @@ private function isRoutelessDispatch(DispatchContext $context): bool
 
     private function routeDispatch(DispatchContext $context): void
     {
-        $this->applyBasePath($context);
-
         $matchedByPath = $this->getMatchedRoutesByPath($context);
         /** @var array<int, AbstractRoute> $matchedArray */
         $matchedArray = iterator_to_array($matchedByPath);
@@ -140,30 +134,13 @@ private function routeDispatch(DispatchContext $context): void
         }
     }
 
-    private function applyBasePath(DispatchContext $context): void
-    {
-        $basePath = $this->routeProvider->getBasePath();
-        if ($basePath === '') {
-            return;
-        }
-
-        $context->setPath(
-            preg_replace(
-                '#^' . preg_quote($basePath) . '#',
-                '',
-                $context->path(),
-            ) ?? $context->path(),
-        );
-    }
-
     /** @param array<int, mixed> $params */
     private function configureContext(
         DispatchContext $context,
         AbstractRoute $route,
         array $params = [],
     ): DispatchContext {
-        $context->route = $route;
-        $context->params = $params;
+        $context->configureRoute($route, $params);
 
         return $context;
     }
@@ -176,7 +153,7 @@ private function getMatchedRoutesByPath(DispatchContext $context): SplObjectStor
 
         foreach ($this->routeProvider->getRoutes() as $route) {
             $params = [];
-            if (!$this->matchRoute($context, $route, $params)) {
+            if (!$route->match($context, $params)) {
                 continue;
             }
 
@@ -265,21 +242,6 @@ private function hasExplicitOptionsRoute(SplObjectStorage $matchedByPath): bool
         return false;
     }
 
-    /** @param array<int, mixed> $params */
-    private function matchRoute(
-        DispatchContext $context,
-        AbstractRoute $route,
-        array &$params = [],
-    ): bool {
-        if (!$route->match($context, $params)) {
-            return false;
-        }
-
-        $context->route = $route;
-
-        return true;
-    }
-
     /** @param SplObjectStorage<AbstractRoute, array<int, mixed>> $matchedByPath */
     private function routineMatch(
         DispatchContext $context,
@@ -296,7 +258,6 @@ private function routineMatch(
                 /** @var array<int, mixed> $tempParams */
                 $tempParams = $matchedByPath[$route];
                 $context->clearResponseMeta();
-                $context->route = $route;
                 if ($this->routinePipeline->matches($context, $route, $tempParams)) {
                     return $this->configureContext(
                         $context,
diff --git a/src/Router.php b/src/Router.php
index b3ae4c2..deb2b23 100644
--- a/src/Router.php
+++ b/src/Router.php
@@ -15,7 +15,6 @@
 use Respect\Fluent\Resolvers\Ucfirst;
 use Respect\Rest\Routes\AbstractRoute;
 use Respect\Rest\Routines\Routinable;
-use Throwable;
 
 use function array_pop;
 use function assert;
@@ -28,11 +27,8 @@
 use function preg_match;
 use function rtrim;
 use function substr_count;
-use function trigger_error;
 use function usort;
 
-use const E_USER_ERROR;
-
 /**
  * A router that contains many instances of routes.
  *
@@ -47,8 +43,6 @@
  */
 final class Router implements MiddlewareInterface, RequestHandlerInterface, RouteProvider
 {
-    public DispatchContext|null $context = null;
-
     /** @var array<int, Routines\Routinable> */
     protected array $globalRoutines = [];
 
@@ -178,6 +172,9 @@ public function createDispatchContext(ServerRequestInterface $serverRequest): Di
         return new DispatchContext(
             $serverRequest,
             $this->factory,
+            $this->dispatchEngine()->routinePipeline(),
+            $this->handlers,
+            $this->basePath,
         );
     }
 
@@ -256,9 +253,6 @@ public function dispatchEngine(): DispatchEngine
         return $this->dispatchEngine ??= new DispatchEngine(
             $this,
             $this->factory,
-            function (DispatchContext $ctx): void {
-                $this->context = $ctx;
-            },
         );
     }
 
@@ -300,21 +294,6 @@ static function (AbstractRoute $a, AbstractRoute $b): int {
         );
     }
 
-    public function __toString(): string
-    {
-        $string = '';
-        try {
-            $response = $this->context?->response();
-            if ($response !== null) {
-                $string = (string) $response->getBody();
-            }
-        } catch (Throwable $exception) {
-            trigger_error($exception->getMessage(), E_USER_ERROR);
-        }
-
-        return $string;
-    }
-
     /** @param array<int, mixed> $args */
     public function __call(string $method, array $args): AbstractRoute
     {
diff --git a/src/Routes/AbstractRoute.php b/src/Routes/AbstractRoute.php
index 8c8fe47..7860682 100644
--- a/src/Routes/AbstractRoute.php
+++ b/src/Routes/AbstractRoute.php
@@ -193,10 +193,10 @@ public function match(DispatchContext $context, array &$params = []): bool
             }
 
             if ($suffix !== '') {
-                $context->request = $context->request->withAttribute(
+                $context->withRequest($context->request->withAttribute(
                     'respect.ext.remaining',
                     $suffix,
-                );
+                ));
             }
         }
 
diff --git a/src/Routines/AbstractAccept.php b/src/Routines/AbstractAccept.php
index 528880e..1b612c9 100644
--- a/src/Routines/AbstractAccept.php
+++ b/src/Routines/AbstractAccept.php
@@ -107,7 +107,7 @@ protected function notifyDeclined(
         DispatchContext $context,
         array $params,
     ): void {
-        $this->forgetNegotiatedCallback();
+        $this->forgetNegotiatedCallback($context);
         $context->prepareResponse(406);
     }
 
diff --git a/src/Routines/AbstractCallbackMediator.php b/src/Routines/AbstractCallbackMediator.php
index 495e775..821de7f 100644
--- a/src/Routines/AbstractCallbackMediator.php
+++ b/src/Routines/AbstractCallbackMediator.php
@@ -5,7 +5,9 @@
 namespace Respect\Rest\Routines;
 
 use Respect\Rest\DispatchContext;
-use SplObjectStorage;
+
+use function is_callable;
+use function spl_object_id;
 
 /**
  * Mediates the callback selection process when choosing the appropriate
@@ -15,9 +17,6 @@
 // phpcs:ignore SlevomatCodingStandard.Classes.SuperfluousAbstractClassNaming.SuperfluousPrefix
 abstract class AbstractCallbackMediator extends CallbackList implements ProxyableWhen
 {
-    /** @var SplObjectStorage<DispatchContext, callable>|false|null */
-    protected SplObjectStorage|false|null $negotiated = null;
-
     /** @param array<int, mixed> $params */
     public function when(DispatchContext $context, array $params): mixed
     {
@@ -76,27 +75,25 @@ abstract protected function notifyDeclined(
 
     protected function getNegotiatedCallback(DispatchContext $context): callable|null
     {
-        if (!$this->negotiated instanceof SplObjectStorage || !$this->negotiated->offsetExists($context)) {
-            return null;
-        }
+        $value = $context->request->getAttribute($this->negotiatedAttributeKey());
 
-        return $this->negotiated[$context];
+        return is_callable($value) ? $value : null;
     }
 
     protected function rememberNegotiatedCallback(DispatchContext $context, callable $callback): void
     {
-        if (!$this->negotiated instanceof SplObjectStorage) {
-            /** @var SplObjectStorage<DispatchContext, callable> $storage */
-            $storage = new SplObjectStorage();
-            $this->negotiated = $storage;
-        }
-
-        $this->negotiated[$context] = $callback;
+        $context->withRequest($context->request->withAttribute(
+            $this->negotiatedAttributeKey(),
+            $callback,
+        ));
     }
 
-    protected function forgetNegotiatedCallback(): void
+    protected function forgetNegotiatedCallback(DispatchContext $context): void
     {
-        $this->negotiated = false;
+        $context->withRequest($context->request->withAttribute(
+            $this->negotiatedAttributeKey(),
+            false,
+        ));
     }
 
     protected function authorize(string $requested, string $provided): mixed
@@ -104,6 +101,11 @@ protected function authorize(string $requested, string $provided): mixed
         return $requested == $provided;
     }
 
+    private function negotiatedAttributeKey(): string
+    {
+        return 'rest.negotiated.' . spl_object_id($this);
+    }
+
     /** @param array<int, mixed> $params */
     private function mediate(string &$requested, string &$provided, DispatchContext $context, array $params): bool
     {
diff --git a/src/Routines/ContentType.php b/src/Routines/ContentType.php
index c2fc636..602efea 100644
--- a/src/Routines/ContentType.php
+++ b/src/Routines/ContentType.php
@@ -33,7 +33,7 @@ public function by(DispatchContext $context, array $params): mixed
             $psrRequest = $psrRequest->withParsedBody($payload);
         }
 
-        $context->request = $psrRequest;
+        $context->withRequest($psrRequest);
 
         return null;
     }
@@ -83,7 +83,7 @@ protected function notifyDeclined(
         DispatchContext $context,
         array $params,
     ): void {
-        $this->forgetNegotiatedCallback();
+        $this->forgetNegotiatedCallback($context);
         $context->prepareResponse(415);
     }
 
diff --git a/src/Routines/FileExtension.php b/src/Routines/FileExtension.php
index ea720b4..d1bbbf6 100644
--- a/src/Routines/FileExtension.php
+++ b/src/Routines/FileExtension.php
@@ -5,8 +5,9 @@
 namespace Respect\Rest\Routines;
 
 use Respect\Rest\DispatchContext;
-use SplObjectStorage;
 
+use function is_callable;
+use function spl_object_id;
 use function str_ends_with;
 use function strlen;
 use function substr;
@@ -19,9 +20,6 @@ final class FileExtension extends CallbackList implements
 {
     private const string REMAINING_ATTRIBUTE = 'respect.ext.remaining';
 
-    /** @var SplObjectStorage<DispatchContext, callable>|null */
-    private SplObjectStorage|null $negotiated = null;
-
     /** @return array<int, string> */
     public function getExtensions(): array
     {
@@ -46,11 +44,14 @@ public function by(DispatchContext $context, array $params): mixed
             }
 
             $remaining = substr($remaining, 0, -strlen($ext));
-            $context->request = $context->request->withAttribute(
+            $context->withRequest($context->request->withAttribute(
                 self::REMAINING_ATTRIBUTE,
                 $remaining,
-            );
-            $this->remember($context, $this->getCallback($ext));
+            ));
+            $context->withRequest($context->request->withAttribute(
+                $this->negotiatedAttributeKey(),
+                $this->getCallback($ext),
+            ));
 
             return null;
         }
@@ -61,21 +62,13 @@ public function by(DispatchContext $context, array $params): mixed
     /** @param array<int, mixed> $params */
     public function through(DispatchContext $context, array $params): mixed
     {
-        if (!$this->negotiated instanceof SplObjectStorage || !$this->negotiated->offsetExists($context)) {
-            return null;
-        }
+        $value = $context->request->getAttribute($this->negotiatedAttributeKey());
 
-        return $this->negotiated[$context];
+        return is_callable($value) ? $value : null;
     }
 
-    private function remember(DispatchContext $context, callable $callback): void
+    private function negotiatedAttributeKey(): string
     {
-        if (!$this->negotiated instanceof SplObjectStorage) {
-            /** @var SplObjectStorage<DispatchContext, callable> $storage */
-            $storage = new SplObjectStorage();
-            $this->negotiated = $storage;
-        }
-
-        $this->negotiated[$context] = $callback;
+        return 'rest.fileext.' . spl_object_id($this);
     }
 }
diff --git a/src/Routines/UserAgent.php b/src/Routines/UserAgent.php
index f220de2..0cb0abe 100644
--- a/src/Routines/UserAgent.php
+++ b/src/Routines/UserAgent.php
@@ -38,10 +38,10 @@ public function by(DispatchContext $context, array $params): mixed
             return $result;
         }
 
-        $context->request = $context->request->withAttribute(
+        $context->withRequest($context->request->withAttribute(
             self::THROUGH_ATTRIBUTE,
             $this->normalizeThroughResult($result),
-        );
+        ));
 
         return null;
     }
@@ -95,7 +95,7 @@ protected function notifyDeclined(
         DispatchContext $context,
         array $params,
     ): void {
-        $this->forgetNegotiatedCallback();
+        $this->forgetNegotiatedCallback($context);
     }
 
     protected function authorize(string $requested, string $provided): mixed
diff --git a/tests/DispatchContextTest.php b/tests/DispatchContextTest.php
index ac81132..258000d 100644
--- a/tests/DispatchContextTest.php
+++ b/tests/DispatchContextTest.php
@@ -136,11 +136,11 @@ public function testResponseIsNullWithoutSettingARoute(DispatchContext $context)
     #[Depends('testIsPossibleToConstructUsingValuesFromSuperglobals')]
     public function testContextIsAbleToDeliverAResponseWithoutSettingPathParams(DispatchContext $context): void
     {
-        $context->route = $this->getMockForRoute(
+        $context->configureRoute($this->getMockForRoute(
             'GET',
             '/notebooks',
             ['Vaio', 'MacBook', 'ThinkPad'],
-        );
+        ));
         $response = $context->response();
 
         self::assertNotNull($response, 'Response should not be null');
@@ -155,14 +155,13 @@ public function testContextIsAbleToDeliverAResponseWithoutSettingPathParams(Disp
     #[Depends('testIsPossibleToConstructUsingValuesFromSuperglobals')]
     public function testContextIsAbleToDeliverAResponseUsingPreviouslySetPathParams(DispatchContext $context): void
     {
-        $context->route = $this->getMockForRoute(
+        $context->configureRoute($this->getMockForRoute(
             'GET',
             '/printers',
             'Some Printers Response',
             'GET',
             ['dpi', 'price'],
-        );
-        $context->params = ['dpi', 'price'];
+        ), ['dpi', 'price']);
         $response = $context->response();
 
         self::assertNotNull($response);
@@ -179,7 +178,7 @@ public function testForwardReplacesRouteAndReturnsResponse(): void
         $context = $this->newContext(new ServerRequest('GET', '/users/alganet/lists'));
         $inactiveRoute  = $this->getMockForRoute('GET', '/users/alganet/lists');
         $forwardedRoute = $this->getMockForRoute('GET', '/lists/12345', 'Some list items');
-        $context->route = $inactiveRoute;
+        $context->configureRoute($inactiveRoute);
         $context->forward($forwardedRoute);
 
         self::assertNotSame(
@@ -237,7 +236,7 @@ static function () use ($internallyForwardedRoute) {
         }
 
         $context = $this->newContext(new ServerRequest('GET', '/cupcakes'));
-        $context->route = $userImplementedRoute;
+        $context->configureRoute($userImplementedRoute);
         $response = $context->response();
 
         self::assertNotNull($response);
@@ -263,7 +262,7 @@ public function testDeveloperCanAbortRequestReturningFalseOnByRoutine(): void
             ->method('by')
             ->willReturn(false);
         $route->appendRoutine($routine);
-        $context->route = $route;
+        $context->configureRoute($route);
 
         $response = $context->response();
 
@@ -300,7 +299,7 @@ public function testDeveloperCanReturnResponseInterfacesOnByRoutine(): void
                     ->withBody($factory->createStream('blocked by routine')),
             );
         $route->appendRoutine($routine);
-        $context->route = $route;
+        $context->configureRoute($route);
 
         $response = $context->response();
 
@@ -328,7 +327,7 @@ public function testDeveloperCanReturnCallablesToProcessOutputAfterTargetRuns():
                     return str_replace('-', ' ', $thatLogStubReturnedAbove);
             });
         $route->appendRoutine($routine);
-        $context->route = $route;
+        $context->configureRoute($route);
         $response = $context->response();
 
         self::assertNotNull($response);
@@ -342,7 +341,7 @@ public function testDeveloperCanReturnCallablesToProcessOutputAfterTargetRuns():
     public function testConvertingToStringCallsResponse(): void
     {
         $context = $this->newContext(new ServerRequest('GET', '/users/alganet/lists'));
-        $context->route = $this->getMockForRoute('GET', '/users/alganet/lists', 'Some list items');
+        $context->configureRoute($this->getMockForRoute('GET', '/users/alganet/lists', 'Some list items'));
         $toString = (string) $context;
 
         self::assertSame('Some list items', $toString);
@@ -369,7 +368,7 @@ public function testContextAcceptsAnInjectedResponder(): void
         $context = $this->newContext(new ServerRequest('GET', '/users/alganet/lists'));
         $factory = new Psr17Factory();
         $context->setResponder(new Responder($factory));
-        $context->route = $this->getMockForRoute('GET', '/users/alganet/lists', 'Some list items');
+        $context->configureRoute($this->getMockForRoute('GET', '/users/alganet/lists', 'Some list items'));
 
         $response = $context->response();
 
@@ -380,13 +379,13 @@ public function testContextAcceptsAnInjectedResponder(): void
     public function test_exception_rethrown_when_no_exception_route_matches(): void
     {
         $context = $this->newContext(new ServerRequest('GET', '/'));
-        $context->route = $this->getMockForRoute(
+        $context->configureRoute($this->getMockForRoute(
             'GET',
             '/',
             static function (): never {
                 throw new RuntimeException('boom');
             },
-        );
+        ));
 
         $this->expectException(RuntimeException::class);
         $this->expectExceptionMessage('boom');
diff --git a/tests/DispatchEngineTest.php b/tests/DispatchEngineTest.php
index 9dd8362..4f3e5b2 100644
--- a/tests/DispatchEngineTest.php
+++ b/tests/DispatchEngineTest.php
@@ -149,28 +149,6 @@ public function testHandlePropagatesUnhandledExceptions(): void
         $engine->handle(new ServerRequest('GET', '/boom'));
     }
 
-    public function testOnContextReadyCallbackIsInvoked(): void
-    {
-        $captured = null;
-        $provider = $this->createStub(RouteProvider::class);
-        $provider->method('getRoutes')->willReturn([
-            new StaticValue('GET', '/test', 'ok'),
-        ]);
-        $provider->method('getBasePath')->willReturn('');
-
-        $engine = new DispatchEngine(
-            $provider,
-            $this->factory,
-            static function ($context) use (&$captured): void {
-                $captured = $context;
-            },
-        );
-
-        $context = $engine->dispatch(new ServerRequest('GET', '/test'));
-
-        self::assertSame($context, $captured);
-    }
-
     public function testGlobalOptions404WhenNoRoutes(): void
     {
         $engine = $this->engine([]);
diff --git a/tests/RouterTest.php b/tests/RouterTest.php
index 7fa1fcf..c3a3c78 100644
--- a/tests/RouterTest.php
+++ b/tests/RouterTest.php
@@ -41,7 +41,6 @@
 use function json_encode;
 use function mb_convert_encoding;
 use function range;
-use function spl_object_hash;
 use function str_repeat;
 use function str_split;
 use function stream_filter_append;
@@ -545,12 +544,12 @@ public function testOptionsRequestShouldReturnBadRequestWhenExplicitOptionsRoute
     public function testOptionsHandlerShouldMaterializeRoutelessResponseWhenNoExplicitRouteSurvives(): void
     {
         $router = self::newRouter();
-        $router->context = self::newContextForRouter($router, new ServerRequest('OPTIONS', '/asian'));
+        $context = self::newContextForRouter($router, new ServerRequest('OPTIONS', '/asian'));
 
         $handleOptionsRequest = new ReflectionMethod($router->dispatchEngine(), 'handleOptionsRequest');
-        $handleOptionsRequest->invoke($router->dispatchEngine(), $router->context, ['OPTIONS'], new SplObjectStorage());
+        $handleOptionsRequest->invoke($router->dispatchEngine(), $context, ['OPTIONS'], new SplObjectStorage());
 
-        $response = $router->context->response();
+        $response = $context->response();
 
         self::assertNotNull($response);
         self::assertSame(204, $response->getStatusCode());
@@ -561,19 +560,24 @@ public function testOptionsHandlerShouldMaterializeRoutelessResponseWhenNoExplic
     // OldRouterTest unique methods
     // =========================================================================
 
-    /** @covers \Respect\Rest\Router */
-    public function testNotRoutableController(): void
+    /**
+     * A controller (stdClass) with no HTTP method handlers produces 500
+     * because the route path matches but no method can be dispatched.
+     *
+     * @covers \Respect\Rest\Router
+     */
+    public function testNotRoutableControllerReturns500(): void
     {
-        self::expectException('InvalidArgumentException');
         $this->router->instanceRoute('ANY', '/', new stdClass());
-        self::responseBody($this->router->dispatch(new ServerRequest('get', '/')));
+        $response = $this->router->handle(new ServerRequest('GET', '/'));
+        self::assertSame(500, $response->getStatusCode());
     }
 
-    public function testNotRoutableControllerByName(): void
+    public function testNotRoutableControllerByNameReturns500(): void
     {
-        self::expectException('InvalidArgumentException');
         $this->router->classRoute('ANY', '/', '\\stdClass');
-        self::responseBody($this->router->dispatch(new ServerRequest('get', '/')));
+        $response = $this->router->handle(new ServerRequest('GET', '/'));
+        self::assertSame(500, $response->getStatusCode());
     }
 
     #[DataProvider('providerForSingleRoutes')]
@@ -2565,31 +2569,14 @@ public function test_when_should_be_called_only_on_existent_methods(): void
         self::assertEquals('"blub"', $out);
     }
 
-    public function test_request_should_be_available_from_router_after_dispatching(): void
+    public function test_dispatch_context_is_passed_through_to_route_callback(): void
     {
         $router = self::newRouter();
-        $request = self::newContextForRouter($router, new ServerRequest('get', '/foo'));
-        $phpunit = $this;
-        $router->get('/foo', static function () use ($router, $request, $phpunit) {
-            $phpunit->assertSame($request, $router->context);
-
-            return spl_object_hash($router->context);
-        });
-        $response = $router->dispatchContext($request)->response();
+        $context = self::newContextForRouter($router, new ServerRequest('get', '/foo'));
+        $router->get('/foo', static fn() => 'dispatched');
+        $response = $router->dispatchContext($context)->response();
         self::assertNotNull($response);
-        $out = (string) $response->getBody();
-        self::assertEquals($out, spl_object_hash($request));
-    }
-
-    /** @covers Respect\Rest\Router::__toString */
-    public function testToStringReturnsCurrentDispatchResponseBody(): void
-    {
-        $router = self::newRouter();
-        $router->get('/foo', 'bar');
-
-        $router->dispatch(new ServerRequest('GET', '/foo'));
-
-        self::assertSame('bar', (string) $router);
+        self::assertSame('dispatched', (string) $response->getBody());
     }
 
     private static function responseBody(DispatchContext $request): string
diff --git a/tests/Routes/ErrorTest.php b/tests/Routes/ErrorTest.php
index 7787f73..89477e8 100644
--- a/tests/Routes/ErrorTest.php
+++ b/tests/Routes/ErrorTest.php
@@ -10,6 +10,7 @@
 use PHPUnit\Framework\TestCase;
 use Respect\Rest\Router;
 
+use function count;
 use function trigger_error;
 
 use const E_USER_WARNING;
@@ -53,4 +54,25 @@ public function testMagicConstuctorCanCreateRoutesToErrors(): void
             'An error should be caught by the router and forwarded',
         );
     }
+
+    #[RunInSeparateProcess]
+    public function testErrorStateDoesNotLeakBetweenDispatches(): void
+    {
+        $router = new Router('', new Psr17Factory());
+        $router->onError(static fn(array $errors) => 'errors: ' . count($errors));
+        $router->get('/warn', static function (): string {
+            trigger_error('warning1', E_USER_WARNING);
+
+            return 'warned';
+        });
+        $router->get('/ok', static fn() => 'clean');
+
+        // First dispatch triggers an error
+        $resp1 = $router->handle(new ServerRequest('GET', '/warn'));
+        self::assertSame('errors: 1', (string) $resp1->getBody());
+
+        // Second dispatch should not inherit the first request's errors
+        $resp2 = $router->handle(new ServerRequest('GET', '/ok'));
+        self::assertSame('clean', (string) $resp2->getBody());
+    }
 }
diff --git a/tests/Routes/ExceptionTest.php b/tests/Routes/ExceptionTest.php
index 83e2901..f856bdf 100644
--- a/tests/Routes/ExceptionTest.php
+++ b/tests/Routes/ExceptionTest.php
@@ -89,4 +89,22 @@ public function testExceptionRouteWorksViaHandle(): void
         self::assertSame(200, $response->getStatusCode());
         self::assertSame('handled: boom', (string) $response->getBody());
     }
+
+    public function testExceptionStateDoesNotLeakBetweenDispatches(): void
+    {
+        $router = new Router('', new Psr17Factory());
+        $router->onException('Throwable', static fn(Throwable $e) => 'error: ' . $e->getMessage());
+        $router->get('/fail', static function (): void {
+            throw new RuntimeException('first');
+        });
+        $router->get('/ok', static fn() => 'success');
+
+        // First dispatch throws
+        $resp1 = $router->handle(new ServerRequest('GET', '/fail'));
+        self::assertSame('error: first', (string) $resp1->getBody());
+
+        // Second dispatch should not see the first exception
+        $resp2 = $router->handle(new ServerRequest('GET', '/ok'));
+        self::assertSame('success', (string) $resp2->getBody());
+    }
 }
diff --git a/tests/RoutinePipelineTest.php b/tests/RoutinePipelineTest.php
index a5e334f..3c6159d 100644
--- a/tests/RoutinePipelineTest.php
+++ b/tests/RoutinePipelineTest.php
@@ -32,7 +32,7 @@ public function testMatchesReturnsTrueWithNoWhenRoutines(): void
     {
         $route = new Callback('GET', '/test', static fn(): string => 'ok');
         $context = $this->newContext();
-        $context->route = $route;
+        $context->configureRoute($route);
         $params = [];
 
         self::assertTrue($this->pipeline->matches($context, $route, $params));
@@ -43,7 +43,7 @@ public function testMatchesReturnsFalseWhenWhenRoutineReturnsFalse(): void
         $route = new Callback('GET', '/test', static fn(): string => 'ok');
         $route->appendRoutine(new When(static fn(): bool => false));
         $context = $this->newContext();
-        $context->route = $route;
+        $context->configureRoute($route);
         $params = [];
 
         self::assertFalse($this->pipeline->matches($context, $route, $params));
@@ -54,7 +54,7 @@ public function testMatchesReturnsTrueWhenWhenRoutineReturnsTrue(): void
         $route = new Callback('GET', '/test', static fn(): string => 'ok');
         $route->appendRoutine(new When(static fn(): bool => true));
         $context = $this->newContext();
-        $context->route = $route;
+        $context->configureRoute($route);
         $params = [];
 
         self::assertTrue($this->pipeline->matches($context, $route, $params));
@@ -64,7 +64,7 @@ public function testProcessByReturnsNullWithNoByRoutines(): void
     {
         $route = new Callback('GET', '/test', static fn(): string => 'ok');
         $context = $this->newContext();
-        $context->route = $route;
+        $context->configureRoute($route);
 
         self::assertNull($this->pipeline->processBy($context, $route));
     }
@@ -75,7 +75,7 @@ public function testProcessByReturnsResponseWhenByReturnsResponse(): void
         $response = $this->factory->createResponse(401);
         $route->appendRoutine(new By(static fn() => $response));
         $context = $this->newContext();
-        $context->route = $route;
+        $context->configureRoute($route);
 
         $result = $this->pipeline->processBy($context, $route);
 
@@ -88,7 +88,7 @@ public function testProcessByReturnsFalseWhenByReturnsFalse(): void
         $route = new Callback('GET', '/test', static fn(): string => 'ok');
         $route->appendRoutine(new By(static fn(): bool => false));
         $context = $this->newContext();
-        $context->route = $route;
+        $context->configureRoute($route);
 
         self::assertFalse($this->pipeline->processBy($context, $route));
     }
@@ -99,7 +99,7 @@ public function testProcessThroughChainsCallableResults(): void
         $route->appendRoutine(new Through(static fn() => static fn(string $v): string => $v . '-A'));
         $route->appendRoutine(new Through(static fn() => static fn(string $v): string => $v . '-B'));
         $context = $this->newContext();
-        $context->route = $route;
+        $context->configureRoute($route);
 
         $result = $this->pipeline->processThrough($context, $route, 'start');
 
@@ -111,7 +111,7 @@ public function testProcessThroughSkipsNonCallableResults(): void
         $route = new Callback('GET', '/test', static fn(): string => 'ok');
         $route->appendRoutine(new Through(static fn(): null => null));
         $context = $this->newContext();
-        $context->route = $route;
+        $context->configureRoute($route);
 
         $result = $this->pipeline->processThrough($context, $route, 'unchanged');
 
diff --git a/tests/Routines/AuthBasicTest.php b/tests/Routines/AuthBasicTest.php
index e39147a..5c5031e 100644
--- a/tests/Routines/AuthBasicTest.php
+++ b/tests/Routines/AuthBasicTest.php
@@ -52,7 +52,7 @@ public function test_pass_all_params_to_callback(): void
             ->withHeader('Authorization', 'Basic ' . base64_encode($user . ':' . $pass));
         $factory = new Psr17Factory();
         $context = new DispatchContext($serverRequest, $factory);
-        $context->route = $this->createRouteWithResponseFactory();
+        $context->configureRoute($this->createRouteWithResponseFactory());
 
         $routine = new AuthBasic('auth realm', [$this, 'shunt_wantedParams']);
         $routine->by($context, [$param1, $param2]);