fix(interactive-subagents): avoid Orca polling fan-out

extensions/interactive-subagents/pi-extension/subagents/orca.ts

@@ -14,6 +14,7 @@ const execFileAsync = promisify(execFile);
 
 /** GNOME screen reader path — never a valid Orca CLI. */
 const GNOME_SCREEN_READER = "/usr/bin/orca";
+const ASYNC_READ_SCREEN_TIMEOUT_MS = 5_000;
 
 let cachedCli: string | null | undefined;
 
@@ -275,14 +276,26 @@ export function readScreen(surface: string, lines = 50): string {
   return parseReadTail(output);
 }
 
-export async function readScreenAsync(surface: string, lines = 50): Promise<string> {
-  const cli = requireOrca();
+async function readScreenWithCli(
+  cli: string,
+  surface: string,
+  lines: number,
+  timeout = ASYNC_READ_SCREEN_TIMEOUT_MS,
+): Promise<string> {
   const { stdout } = await execFileAsync(cli, readScreenArgs(surface, lines), {
     encoding: "utf8",
+    timeout,
+    killSignal: "SIGKILL",
   });
   return parseReadTail(stdout);
 }
 
+export async function readScreenAsync(surface: string, lines = 50): Promise<string> {
+  return readScreenWithCli(requireOrca(), surface, lines);
+}
+
+export const __orcaTest__ = { readScreenWithCli };
+
 export function closeSurface(surface: string): void {
   const cli = requireOrca();
   const args = ["terminal", "close", "--terminal", surface];

extensions/interactive-subagents/pi-extension/subagents/surface.ts

@@ -153,18 +153,28 @@ function readCompletionFile(path: string): PollResult | null {
   return { reason: "sentinel", exitCode };
 }
 
+type PollOptions = {
+  interval: number;
+  sessionFile?: string;
+  sentinelFile?: string;
+  completionFile?: string;
+  onTick?: (elapsed: number) => void;
+};
+
+/** Avoid launching a terminal CLI reader when a local completion signal is authoritative. */
+function shouldPollSurface(
+  options: Pick<PollOptions, "sessionFile" | "sentinelFile" | "completionFile">,
+): boolean {
+  return !options.sessionFile && !options.sentinelFile && !options.completionFile;
+}
+
 export const __pollForExitTest__ = { interpretExitSidecar, readCompletionFile };
 
 export async function pollForExit(
   surface: string,
   signal: AbortSignal,
-  options: {
-    interval: number;
-    sessionFile?: string;
-    sentinelFile?: string;
-    completionFile?: string;
-    onTick?: (elapsed: number) => void;
-  },
+  options: PollOptions,
+  readSurface: (surface: string, lines?: number) => Promise<string> = readScreenAsync,
 ): Promise<PollResult> {
   const start = Date.now();
 
@@ -197,12 +207,14 @@ export async function pollForExit(
       } catch {}
     }
 
-    try {
-      const screen = await readScreenAsync(surface, 5);
-      const match = screen.match(/__SUBAGENT_DONE_(\d+)__/);
-      if (match) return { reason: "sentinel", exitCode: Number.parseInt(match[1], 10) };
-    } catch {
-      // Surface reads are best-effort. Filesystem completion remains authoritative.
+    if (shouldPollSurface(options)) {
+      try {
+        const screen = await readSurface(surface, 5);
+        const match = screen.match(/__SUBAGENT_DONE_(\d+)__/);
+        if (match) return { reason: "sentinel", exitCode: Number.parseInt(match[1], 10) };
+      } catch {
+        // Surface reads are a best-effort fallback when no completion file is available.
+      }
     }
 
     const elapsed = Math.floor((Date.now() - start) / 1000);