Replace unsafe type casts with proper narrowing, enable noUncheckedIndexedAccess

- Use type guard instead of `as` casts in parseCursorEvent
- Narrow run output via `in` checks instead of casting to Record
- Enable noUncheckedIndexedAccess in tsconfig for safer indexing

Author: D-K-P

cursor-cli-demo/components/terminal.tsx

@@ -6,6 +6,13 @@ import type { cursorAgentTask, STREAMS } from "@/trigger/cursor-agent";
 import { parseCursorEvent } from "@/lib/cursor-events";
 import { CursorEventRow } from "./cursor-event";
 
+function getRunErrorMessage(output: unknown): string {
+  if (typeof output !== "object" || output === null) return "Task failed";
+  if ("message" in output && typeof output.message === "string") return output.message;
+  if ("error" in output && typeof output.error === "string") return output.error;
+  return "Task failed";
+}
+
 export function Terminal({
   runId,
   publicAccessToken,
@@ -98,11 +105,7 @@ export function Terminal({
 
       {isFailed && (
         <div className="text-red-400 text-sm">
-          {(() => {
-            const output = run?.output as Record<string, unknown> | undefined;
-            const msg = output?.message ?? output?.error;
-            return typeof msg === "string" ? msg : "Task failed";
-          })()}
+          {getRunErrorMessage(run?.output)}
         </div>
       )}
 

cursor-cli-demo/lib/cursor-events.ts

@@ -64,14 +64,17 @@ export type ResultEvent = {
   session_id: string;
 };
 
-const knownTypes = new Set(["system", "user", "assistant", "tool_call", "result"]);
+const knownTypes = new Set<string>(["system", "user", "assistant", "tool_call", "result"]);
+
+function isCursorEvent(data: unknown): data is CursorEvent {
+  if (typeof data !== "object" || data === null) return false;
+  if (!("type" in data)) return false;
+  return typeof data.type === "string" && knownTypes.has(data.type);
+}
 
 /** Parse raw JSON into a CursorEvent, returns null for unknown types */
 export function parseCursorEvent(data: unknown): CursorEvent | null {
-  if (typeof data !== "object" || data === null || !("type" in data)) return null;
-  const typed = data as { type: string };
-  if (!knownTypes.has(typed.type)) return null;
-  return data as CursorEvent;
+  return isCursorEvent(data) ? data : null;
 }
 
 /** Extract the tool name from a tool_call event */

cursor-cli-demo/tsconfig.json

@@ -9,6 +9,7 @@
     "allowJs": true,
     "skipLibCheck": true,
     "strict": true,
+    "noUncheckedIndexedAccess": true,
     "noEmit": true,
     "esModuleInterop": true,
     "module": "esnext",