diff --git a/packages/provider-acp/src/server/AcpSessionRuntime.ts b/packages/provider-acp/src/server/AcpSessionRuntime.ts
index 683bf8c90f41e3690ea9e0ef639a2f894b5c880b..e40b0c555e5411f19854fb873b8cb1806c753e74 100644
--- a/packages/provider-acp/src/server/AcpSessionRuntime.ts
+++ b/packages/provider-acp/src/server/AcpSessionRuntime.ts
@@ -285,6 +285,13 @@ export function wrapCommandForLinuxCgroup(
         '[ "$actual" = "$expected" ] || exit 126',
         "unset ELECTRON_RUN_AS_NODE T3_ACP_CGROUP_WRAPPER",
         "trap 'exit 125' 0",
+        // The trap alone does not cover a failed `exec`: bash — which is
+        // /bin/sh on Arch derivatives — exits 127 without running the EXIT
+        // trap, so a missing agent binary reported "killed by the wrapper"
+        // instead of "never launched". The caller always hands us an absolute
+        // target, so test it as an executable file rather than asking the
+        // shell to resolve it.
+        '[ -f "$1" ] && [ -x "$1" ] || exit 125',
         'exec "$@"',
       ].join("\n"),
       "t3-acp-cgroup-wrapper",