diff --git a/src/Roux/Server.hs b/src/Roux/Server.hs
index 2a7e3bd..269646d 100644
--- a/src/Roux/Server.hs
+++ b/src/Roux/Server.hs
@@ -244,8 +244,10 @@ readProcessBytes cmd args = do
                 , std_err = CreatePipe
                 }
     result <- createProcess process
+    -- createProcess returns (stdin, stdout, stderr, process).
+    -- stdin is Inherited → Nothing; stdout/stderr are CreatePipe → Just.
     case result of
-        (Just outH, Just errH, _, ph) -> do
+        (Nothing, Just outH, Just errH, ph) -> do
             hSetBinaryMode outH True
             hSetBinaryMode errH True
             out <- LB.hGetContents outH