From cbbd317fb59647a3dfd97c685b060d07eb42e39a Mon Sep 17 00:00:00 2001
From: Abel Yagubyan <abelyagubyan@berkeley.edu>
Date: Wed, 21 Oct 2026 17:53:22 -0400
Subject: [PATCH] fix(process): index late scenario events in validation issues
 (#6160)

Co-authored-by: Abelo9996 <Abelo9996@users.noreply.github.com>
---
 src/domain/process/processScenario.test.ts | 27 ++++++++++++++++++++++
 src/domain/process/processScenario.ts      |  4 ++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/domain/process/processScenario.test.ts b/src/domain/process/processScenario.test.ts
index 529fcc2d9a..450d873673 100644
--- a/src/domain/process/processScenario.test.ts
+++ b/src/domain/process/processScenario.test.ts
@@ -210,3 +210,30 @@ it("applies the selected scrollback budget to every scheduled resize", () => {
     }).success,
   ).toBe(true);
 });
+
+it("identifies each event scheduled after the scenario timeout", () => {
+  const parsed = processScenarioSchema.safeParse({
+    executable: "/bin/true",
+    timeout_ms: 1_000,
+    events: [
+      { type: "input", at_ms: 1_000, data: "a" },
+      { type: "input", at_ms: 1_500, data: "b" },
+      { type: "signal", at_ms: 2_000, signal: "SIGINT" },
+    ],
+  });
+
+  expect(parsed.success).toBe(false);
+  if (parsed.success) throw new Error("expected late event rejection");
+  expect(parsed.error.issues).toEqual([
+    expect.objectContaining({
+      code: "custom",
+      path: ["events", 1],
+      message: "event at 1500 ms occurs after the 1000 ms scenario timeout",
+    }),
+    expect.objectContaining({
+      code: "custom",
+      path: ["events", 2],
+      message: "event at 2000 ms occurs after the 1000 ms scenario timeout",
+    }),
+  ]);
+});
diff --git a/src/domain/process/processScenario.ts b/src/domain/process/processScenario.ts
index bfaab26727..ba1376524e 100644
--- a/src/domain/process/processScenario.ts
+++ b/src/domain/process/processScenario.ts
@@ -298,8 +298,8 @@ export const processScenarioSchema = z
       if (event.at_ms > scenario.timeout_ms) {
         context.addIssue({
           code: "custom",
-          message: "event occurs after the scenario timeout",
-          path: ["events"],
+          message: `event at ${String(event.at_ms)} ms occurs after the ${String(scenario.timeout_ms)} ms scenario timeout`,
+          path: ["events", index],
         });
       }
     }