diff --git a/.Jules/sentinel.md b/.Jules/sentinel.md
index 70f67594..3d52446e 100644
--- a/.Jules/sentinel.md
+++ b/.Jules/sentinel.md
@@ -18,3 +18,7 @@
 **Vulnerability:** The application was falling back to storing OBS passwords as plaintext strings inside exported/saved JSON models (`Macro.swift` and `SystemCommand.swift`) if saving to the macOS Keychain failed.
 **Learning:** Saving secrets to unencrypted formats simply because secure storage fails is a critical anti-pattern known as "failing open" that results in data exposure.
 **Prevention:** Always fail securely. If secure storage operations fail, discard the sensitive credential in memory rather than writing it insecurely to disk, even if it requires the user to re-authenticate later.
+## 2026-06-26 - [Foundation.Process Pipe Deadlock]
+**Vulnerability:** Execution frameworks using `Foundation.Process` to run shell commands or scripts were vulnerable to a pipe deadlock and Denial of Service (DoS) if the child process output exceeded the OS pipe buffer (~64KB).
+**Learning:** Calling `process.waitUntilExit()` before fully reading the child process's output pipe causes the parent to block waiting for the child, while the child blocks waiting for the parent to drain the pipe buffer.
+**Prevention:** Always read data from the pipe (e.g., `pipe.fileHandleForReading.readDataToEndOfFile()`) *before* calling `process.waitUntilExit()` to ensure the pipe is drained as the child writes.
diff --git a/TriggerKit/Sources/TriggerKitRuntime/AutomationExecutor.swift b/TriggerKit/Sources/TriggerKitRuntime/AutomationExecutor.swift
index 59854205..bb8eff77 100644
--- a/TriggerKit/Sources/TriggerKitRuntime/AutomationExecutor.swift
+++ b/TriggerKit/Sources/TriggerKitRuntime/AutomationExecutor.swift
@@ -354,9 +354,10 @@ public final class AutomationExecutor {
 			} catch {
 				return .failure("\(name) launch failed: \(error.localizedDescription)")
 			}
-			process.waitUntilExit()
 
 			let data = pipe.fileHandleForReading.readDataToEndOfFile()
+			process.waitUntilExit()
+
 			let output = String(data: data, encoding: .utf8)?
 				.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
 
@@ -731,11 +732,11 @@ private final class ShellCommandRunner: @unchecked Sendable {
 		pgrep.standardError = FileHandle.nullDevice
 		do {
 			try pgrep.run()
-			pgrep.waitUntilExit()
 		} catch {
 			return []
 		}
 		let data = pipe.fileHandleForReading.readDataToEndOfFile()
+		pgrep.waitUntilExit()
 		let output = String(data: data, encoding: .utf8) ?? ""
 		return output
 			.split(whereSeparator: \.isNewline)
diff --git a/XboxControllerMapper/XboxControllerMapper/Services/Input/UniversalControlMouseRelay.swift b/XboxControllerMapper/XboxControllerMapper/Services/Input/UniversalControlMouseRelay.swift
index 40e97b37..15ecd7cb 100644
--- a/XboxControllerMapper/XboxControllerMapper/Services/Input/UniversalControlMouseRelay.swift
+++ b/XboxControllerMapper/XboxControllerMapper/Services/Input/UniversalControlMouseRelay.swift
@@ -1405,10 +1405,9 @@ final class UniversalControlMouseRelay: @unchecked Sendable {
             NSLog("[UCMouseRelay] Could not run tailscale status: %@", String(describing: error))
             return []
         }
+        let data = pipe.fileHandleForReading.readDataToEndOfFile()
         process.waitUntilExit()
         guard process.terminationStatus == 0 else { return [] }
-
-        let data = pipe.fileHandleForReading.readDataToEndOfFile()
         guard let object = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
               let peers = object["Peer"] as? [String: Any] else {
             return []
diff --git a/XboxControllerMapper/XboxControllerMapperTests/OBSWebSocketLiveIntegrationTests.swift b/XboxControllerMapper/XboxControllerMapperTests/OBSWebSocketLiveIntegrationTests.swift
index 722ba696..c2543442 100644
--- a/XboxControllerMapper/XboxControllerMapperTests/OBSWebSocketLiveIntegrationTests.swift
+++ b/XboxControllerMapper/XboxControllerMapperTests/OBSWebSocketLiveIntegrationTests.swift
@@ -167,9 +167,9 @@ private enum OBSMediaMTXManager {
         which.standardOutput = outPipe
         which.standardError = Pipe()
         try? which.run()
+        let data = outPipe.fileHandleForReading.readDataToEndOfFile()
         which.waitUntilExit()
         if which.terminationStatus == 0 {
-            let data = outPipe.fileHandleForReading.readDataToEndOfFile()
             if let path = String(data: data, encoding: .utf8)?
                 .trimmingCharacters(in: .whitespacesAndNewlines),
                !path.isEmpty,
@@ -246,6 +246,12 @@ private enum OBSMediaMTXManager {
         } catch {
             return false
         }
+        if let outPipe = p.standardOutput as? Pipe {
+            _ = outPipe.fileHandleForReading.readDataToEndOfFile()
+        }
+        if let errPipe = p.standardError as? Pipe {
+            _ = errPipe.fileHandleForReading.readDataToEndOfFile()
+        }
         p.waitUntilExit()
         return p.terminationStatus == 0
     }