diff --git a/includes/class-spacefast-oauth.php b/includes/class-spacefast-oauth.php
index 01badd3..749d7f7 100644
--- a/includes/class-spacefast-oauth.php
+++ b/includes/class-spacefast-oauth.php
@@ -94,7 +94,11 @@ public function begin( string $mode ): array {
 			'code_challenge_method' => 'S256',
 			'resource' => $resource,
 		);
-		return array( 'ok' => true, 'message' => '', 'url' => add_query_arg( $query, $api_url . '/v1/auth/oauth2/authorize' ) );
+		// add_query_arg() deliberately leaves values unencoded. The callback URL
+		// has its own query string, so using it here would turn the callback's
+		// second parameter into a top-level authorization parameter.
+		$url = $api_url . '/v1/auth/oauth2/authorize?' . http_build_query( $query, '', '&', PHP_QUERY_RFC3986 );
+		return array( 'ok' => true, 'message' => '', 'url' => $url );
 	}
 
 	/** @return array{ok:bool,message:string} */
diff --git a/readme.txt b/readme.txt
index 5a3ee72..e7b81e0 100644
--- a/readme.txt
+++ b/readme.txt
@@ -3,7 +3,7 @@ Contributors: spacefast
 Tags: static site, headless cms, simply static, deployment
 Requires at least: 6.5
 Requires PHP: 8.1
-Stable tag: 0.3.1
+Stable tag: 0.3.2
 License: GPLv2 or later
 
 Publish a Simply Static export to Spacefast, or rebuild a headless site when WordPress content changes.
@@ -31,6 +31,9 @@ OAuth access is limited to the Team you authorize and the mode you choose. WordP
 
 == Changelog ==
 
+= 0.3.2 =
+* Preserve the complete WordPress admin callback URL during Spacefast authorization.
+
 = 0.3.1 =
 * Debounce automatic headless builds until public content has been quiet for 60 seconds.
 * Keep manual builds immediate and avoid duplicate scheduled delivery afterward.
diff --git a/spacefast-wordpress.php b/spacefast-wordpress.php
index 17076b6..f390b85 100644
--- a/spacefast-wordpress.php
+++ b/spacefast-wordpress.php
@@ -3,7 +3,7 @@
  * Plugin Name: Spacefast
  * Plugin URI: https://spacefast.com/
  * Description: Publishes static WordPress exports or rebuilds a headless Spacefast site.
- * Version: 0.3.1
+ * Version: 0.3.2
  * Update URI: https://github.com/spacefast/wordpress
  * Requires at least: 6.5
  * Requires PHP: 8.1
@@ -14,7 +14,7 @@
 
 defined( 'ABSPATH' ) || exit;
 
-define( 'SPACEFAST_WORDPRESS_VERSION', '0.3.1' );
+define( 'SPACEFAST_WORDPRESS_VERSION', '0.3.2' );
 define( 'SPACEFAST_WORDPRESS_FILE', __FILE__ );
 
 require_once __DIR__ . '/includes/class-spacefast-settings.php';
diff --git a/tests/acceptance/wordpress.php b/tests/acceptance/wordpress.php
index d8504df..dd8a169 100644
--- a/tests/acceptance/wordpress.php
+++ b/tests/acceptance/wordpress.php
@@ -71,7 +71,7 @@ function spacefast_accept( bool $condition, string $message ): void {
 );
 
 $plugin = get_plugin_data( WP_PLUGIN_DIR . '/spacefast-wordpress/spacefast-wordpress.php', false, false );
-spacefast_accept( '0.3.1' === $plugin['Version'], 'Unexpected plugin version.' );
+spacefast_accept( '0.3.2' === $plugin['Version'], 'Unexpected plugin version.' );
 spacefast_accept( 'https://github.com/spacefast/wordpress' === $plugin['UpdateURI'], 'Update URI is missing.' );
 
 Spacefast_Settings::disconnect();
diff --git a/tests/behavior.php b/tests/behavior.php
index 65835ce..fe6b0b9 100644
--- a/tests/behavior.php
+++ b/tests/behavior.php
@@ -85,7 +85,13 @@ function admin_url( string $path = '' ): string {
 	return 'https://wp.example.test/wp-admin/' . ltrim( $path, '/' );
 }
 function add_query_arg( array $args, string $url ): string {
-	return $url . ( str_contains( $url, '?' ) ? '&' : '?' ) . http_build_query( $args, '', '&', PHP_QUERY_RFC3986 );
+	// WordPress build_query() leaves values unencoded. This matters when a
+	// query argument is itself a URL with its own query string.
+	$pairs = array();
+	foreach ( $args as $key => $value ) {
+		$pairs[] = $key . '=' . $value;
+	}
+	return $url . ( str_contains( $url, '?' ) ? '&' : '?' ) . implode( '&', $pairs );
 }
 function home_url(): string {
 	return 'https://wp.example.test';
@@ -249,6 +255,12 @@ function raw_response( int $status, array $data = array() ): array {
 	'binds tokens to the Spacefast API resource'
 );
 check( str_contains( (string) $authorization['url'], 'code_challenge_method=S256' ), 'authorization uses PKCE S256' );
+$authorization_query = array();
+parse_str( (string) parse_url( (string) $authorization['url'], PHP_URL_QUERY ), $authorization_query );
+check(
+	Spacefast_OAuth::callback_url() === ( $authorization_query['redirect_uri'] ?? '' ),
+	'authorization preserves the complete query-bearing WordPress callback URI'
+);
 $pending = get_option( Spacefast_OAuth::PENDING_OPTION );
 $finished = $oauth->finish( 'authorization-code', (string) $pending['state'] );
 check( true === $finished['ok'], 'valid callback exchanges its code and loads Team-scoped choices' );