diff --git a/scripts/scenarios/start-app.ts b/scripts/scenarios/start-app.ts
index 5dee3f26c1..df66026c5b 100644
--- a/scripts/scenarios/start-app.ts
+++ b/scripts/scenarios/start-app.ts
@@ -22,7 +22,7 @@ import { ScenarioError } from "./shell.ts";
 // The dev runner's web port is 5733 plus an offset. Mirror of BASE_WEB_PORT in dev-runner.ts.
 const BASE_WEB_PORT = 5733;
 // The replay agent `vp run dev` registers: free, recorded turns through the real adapter.
-const REPLAY = { instanceId: "devReplay", model: "showcase" };
+const REPLAY = { instanceId: "devReplay", model: "multi-turn" };
 // Generated text (titles) cannot go to the replay agent: the server swaps an ACP agent for the
 // first enabled real provider, else its default, Codex. So every provider it could fall back to
 // is off and Codex is a command that only fails: no run reaches a paid model.
@@ -126,8 +126,20 @@ const startApp = Effect.fn("startApp")(function* (input: {
   const checkout = yield* HostProcess.WorkingDirectory;
   const hostEnvironment = yield* HostProcess.Environment;
   yield* prepareHome(input.home);
+  const replayPath = path.join(checkout, "apps/server/scripts/dev-replay-agent.ts");
+  const replaySource = yield* fs.readFileString(replayPath);
+  if (!replaySource.includes("T3_SCENARIO_RECEIPTS")) {
+    yield* fs.writeFileString(replayPath, replaySource.replace(
+      "const params = message.params ?? {};",
+      `const params = message.params ?? {};
+    if (message.method === "session/prompt" && process.env.T3_SCENARIO_RECEIPTS) {
+      NodeFS.appendFileSync(process.env.T3_SCENARIO_RECEIPTS, JSON.stringify({ prompt: params.prompt }) + "\\n");
+    }`,
+    ));
+  }
   const env = {
     ...hostEnvironment,
+    T3_SCENARIO_RECEIPTS: path.join(input.home, "received-prompts.ndjson"),
     PATH: `${path.join(input.home, "bin")}:${hostEnvironment.PATH ?? ""}`,
     T3CODE_AUTO_BOOTSTRAP_PROJECT_FROM_CWD: "0",
   };