diff --git a/Packages/ICCeryCore/Sources/ICCeryCore/Argyll/ArgyllRunner.swift b/Packages/ICCeryCore/Sources/ICCeryCore/Argyll/ArgyllRunner.swift
index c2eb510..fbbfb9e 100644
--- a/Packages/ICCeryCore/Sources/ICCeryCore/Argyll/ArgyllRunner.swift
+++ b/Packages/ICCeryCore/Sources/ICCeryCore/Argyll/ArgyllRunner.swift
@@ -192,6 +192,18 @@ public struct ArgyllRunner: Sendable {
 
     // MARK: - Shared collection
 
+    /// DEBUG-only fast path: under `ICCERY_UI_TESTING=1` polling/wait
+    /// intervals shrink ~10x — same env convention as `AppPaths.testRoot`.
+    /// Release builds compile the branch out entirely; no static state.
+    private static func testAwareDelay(_ nanos: UInt64) -> UInt64 {
+        #if DEBUG
+        if ProcessInfo.processInfo.environment["ICCERY_UI_TESTING"] == "1" {
+            return nanos / 10
+        }
+        #endif
+        return nanos
+    }
+
     /// Cancels any previous child with the same id and waits for it to
     /// finalize, so `runStreaming` / `runCaptured` never sees a
     /// `duplicateID` from a leftover process (#50, #52).
@@ -200,7 +212,7 @@ public struct ArgyllRunner: Sendable {
         await processManager.kill(id: id)
         var attempts = 0
         while await processManager.isRunning(id), attempts < 30 {
-            try? await Task.sleep(nanoseconds: 100_000_000)
+            try? await Task.sleep(nanoseconds: Self.testAwareDelay(100_000_000))
             attempts += 1
         }
     }
@@ -592,7 +604,7 @@ public struct ArgyllRunner: Sendable {
                 await processManager.setPreKillHook(id: processId) { [processManager] in
                     if isXY {
                         try? await processManager.sendStdin(id: processId, bytes: ChartreadInput.quit.bytes)
-                        try? await Task.sleep(nanoseconds: 500_000_000)
+                        try? await Task.sleep(nanoseconds: Self.testAwareDelay(500_000_000))
                     }
                 }