diff --git a/tests/Integration/PostMatchActionSmokeTest.php b/tests/Integration/PostMatchActionSmokeTest.php
index 5698a1e..1fadea0 100644
--- a/tests/Integration/PostMatchActionSmokeTest.php
+++ b/tests/Integration/PostMatchActionSmokeTest.php
@@ -15,7 +15,6 @@ use PHPUnit\Framework\TestCase;
 final class PostMatchActionSmokeTest extends TestCase
 {
     private const SECRET = 'e2e-smoke-secret';
-    private const MATCH_ID = '0123456789abcdef';
     private const BASE_URL = 'http://127.0.0.1:8765';
     private const CSRF_COOKIE_NAME = '__csrf';
 
@@ -60,14 +59,15 @@ final class PostMatchActionSmokeTest extends TestCase
         $matchId = $startResponse['body']['matchId'] ?? null;
         $turnToken = $startResponse['body']['turnToken'] ?? null;
         self::assertIsArray($match);
-        self::assertSame(self::MATCH_ID, $matchId);
+        self::assertIsString($matchId);
+        self::assertMatchesRegularExpression('/^[a-f0-9]{16,}$/', $matchId);
         self::assertMatchesRegularExpression('/^[a-f0-9]{32}$/', $turnToken);
 
         for ($i = 0; $i < 200; $i += 1) {
             if (!empty($match['winnerTeamId'])) {
                 break;
             }
-            $action = $this->pickAction($match);
+            $action = $this->pickAction($match, $matchId);
             $response = $this->postJson("/matches/current/{$action['verb']}", $action['body']);
             $errMsg = "Step {$i} verb={$action['verb']} failed: " . ($response['body']['error'] ?? '');
             self::assertSame(200, $response['status'], $errMsg);
@@ -83,10 +83,11 @@ final class PostMatchActionSmokeTest extends TestCase
         $startResponse = $this->postJson('/scenarios/skirmish/start', $scenario);
         self::assertSame(200, $startResponse['status']);
         $match = $startResponse['body']['match'];
-        $staleToken = TurnToken::issue(self::SECRET, self::MATCH_ID, 'alpha', 99, 0);
+        $matchId = $startResponse['body']['matchId'];
+        $staleToken = TurnToken::issue(self::SECRET, $matchId, 'alpha', 99, 0);
 
         $response = $this->postJson('/matches/current/end-turn', [
-            'matchId' => self::MATCH_ID,
+            'matchId' => $matchId,
             'match' => $match,
         ], $staleToken);
 
@@ -217,7 +218,7 @@ final class PostMatchActionSmokeTest extends TestCase
             $headers[] = 'X-Turn-Token: ' . $turnToken;
         } elseif (isset($body['match'])) {
             $match = $body['match'];
-            $matchId = (string) ($body['matchId'] ?? self::MATCH_ID);
+            $matchId = (string) ($body['matchId'] ?? '');
             $turnToken = TurnToken::issue(
                 self::SECRET,
                 $matchId,
@@ -254,9 +255,10 @@ final class PostMatchActionSmokeTest extends TestCase
      *  - if no enemy is reachable this turn, end the turn.
      *
      * @param array<string, mixed> $match
+     * @param string $matchId
      * @return array{verb: string, body: array<string, mixed>}
      */
-    private function pickAction(array $match): array
+    private function pickAction(array $match, string $matchId): array
     {
         $units = $match['units'];
         $active = $match['activeTeamId'];
@@ -275,7 +277,7 @@ final class PostMatchActionSmokeTest extends TestCase
                     return [
                         'verb' => 'attack',
                         'body' => [
-                            'matchId' => self::MATCH_ID,
+                            'matchId' => $matchId,
                             'match' => $match,
                             'attackerId' => $unit['id'],
                             'targetId' => $other['id'],
@@ -345,7 +347,7 @@ final class PostMatchActionSmokeTest extends TestCase
                     return [
                         'verb' => 'move',
                         'body' => [
-                            'matchId' => self::MATCH_ID,
+                            'matchId' => $matchId,
                             'match' => $match,
                             'unitId' => $unit['id'],
                             'x' => $c['x'],
@@ -358,7 +360,7 @@ final class PostMatchActionSmokeTest extends TestCase
         return [
             'verb' => 'end-turn',
             'body' => [
-                'matchId' => self::MATCH_ID,
+                'matchId' => $matchId,
                 'match' => $match,
             ],
         ];