diff --git a/bin/omarchy-install-hermes-cli b/bin/omarchy-install-hermes-cli
index 5b6a3598..150364c0 100755
--- a/bin/omarchy-install-hermes-cli
+++ b/bin/omarchy-install-hermes-cli
@@ -88,13 +88,16 @@ hermes_runs() {
     timeout 15 "$HOME/.local/bin/hermes" --version >/dev/null 2>&1
 }
 
-# The chat subcommand's --oneshot opt-out arrived with native interactive -q,
-# so its presence is a stable capability check without relying on a version.
+# Probed for the flags omarchy-agent actually passes -- --query to seed the
+# session and --tui to keep it interactive -- rather than a flag that merely
+# shipped alongside them: the previous marker, --oneshot, was dropped in Hermes
+# v0.20 and left working installs stranded as "not ready".
 hermes_prompt_ready() {
   local help
   hermes_runs &&
     help=$(timeout 15 "$HOME/.local/bin/hermes" chat --help 2>/dev/null) &&
-    grep -qF -- '--oneshot' <<<"$help"
+    grep -qF -- '--tui' <<<"$help" &&
+    grep -qF -- '--query' <<<"$help"
 }
 
 # --owns answers whether the wrapper on PATH is the one this command wrote, so
diff --git a/test/shell.d/hermes-cli-test.sh b/test/shell.d/hermes-cli-test.sh
index 83b516e9..2144a795 100755
--- a/test/shell.d/hermes-cli-test.sh
+++ b/test/shell.d/hermes-cli-test.sh
@@ -98,7 +98,7 @@ mkdir -p "$test_home/.hermes/hermes-agent/venv/bin"
 cat >"$test_home/.hermes/hermes-agent/venv/bin/hermes" <<'SH'
 #!/bin/bash
 if [[ ${1:-} == "chat" && ${2:-} == "--help" ]]; then
-  [[ ${OMARCHY_TEST_HERMES_CAPABLE:-1} == 1 ]] && echo "--oneshot"
+  [[ ${OMARCHY_TEST_HERMES_CAPABLE:-1} == 1 ]] && echo "[-q QUERY, --query QUERY] [--tui]"
 else
   echo "hermes-agent 0.0.0-test"
 fi
@@ -388,7 +388,7 @@ run_ready_check && fail "--check rejects the app's wrapper when its runtime is g
 cat >"$ready_home/.hermes/hermes-agent/venv/bin/hermes" <<'SH'
 #!/bin/bash
 if [[ ${1:-} == "chat" && ${2:-} == "--help" ]]; then
-  echo "--oneshot"
+  echo "[-q QUERY, --query QUERY] [--tui]"
 else
   echo "hermes-agent 0.0.0-test"
 fi
@@ -396,3 +396,17 @@ SH
 chmod +x "$ready_home/.hermes/hermes-agent/venv/bin/hermes"
 run_ready_check || fail "--check accepts the app's wrapper once it runs"
 pass "readiness runs the app's command rather than trusting its marker"
+
+# A release whose help lists only the retired --oneshot marker cannot run the
+# seeded --tui --query session omarchy-agent starts, so it is not ready.
+cat >"$ready_home/.hermes/hermes-agent/venv/bin/hermes" <<'SH'
+#!/bin/bash
+if [[ ${1:-} == "chat" && ${2:-} == "--help" ]]; then
+  echo "--oneshot"
+else
+  echo "hermes-agent 0.0.0-test"
+fi
+SH
+chmod +x "$ready_home/.hermes/hermes-agent/venv/bin/hermes"
+run_ready_check && fail "--check accepts a release without the flags omarchy-agent passes"
+pass "a release listing only --oneshot is not prompt-ready"