diff --git a/scripts/e2e.config.ts b/scripts/e2e.config.ts
index 520fc8338d..61836d08d8 100644
--- a/scripts/e2e.config.ts
+++ b/scripts/e2e.config.ts
@@ -134,7 +134,7 @@ export default {
   targets: [
     {
       name: "web",
-      engine: web({ viewport: { width: 1280, height: 800 } }),
+      engine: web({ browser: "firefox", viewport: { width: 1280, height: 800 } }),
       app: {
         url: `http://${LOOPBACK}:0`,
         // Vite answers before the server does; this path is proxied to the server.
diff --git a/scripts/prove-scenario.ts b/scripts/prove-scenario.ts
index 6b0bb9c1a4..fb50ad0469 100644
--- a/scripts/prove-scenario.ts
+++ b/scripts/prove-scenario.ts
@@ -216,7 +216,7 @@ const runSide = Effect.fn("prove.runSide")(function* (
     // The scenario and e2e come from this checkout; only the app comes from `appDir`.
     run(
       path.join(scripts, "node_modules/.bin/e2e"),
-      ["run", scenarioPath, "--output", path.relative(scripts, outDir)],
+      ["run", scenarioPath, "--target", "web", "--headed", "--output", path.relative(scripts, outDir)],
       {
         cwd: scripts,
         env: { ...environment, T3_SCENARIO_APP_DIR: appDir, E2E_TELEMETRY_DISABLED: "1" },