diff --git a/docs/install-for-codex.md b/docs/install-for-codex.md
index 2c70a1c..37de3ea 100644
--- a/docs/install-for-codex.md
+++ b/docs/install-for-codex.md
@@ -26,12 +26,12 @@ This will:
 - Sync `humanize`, `humanize-gen-plan`, `humanize-refine-plan`, and `humanize-rlcr` into `${CODEX_HOME:-~/.codex}/skills`
 - Copy runtime dependencies into `${CODEX_HOME:-~/.codex}/skills/humanize`
 - Install/update native Humanize Stop hooks in `${CODEX_HOME:-~/.codex}/hooks.json`
-- Enable the experimental `codex_hooks` feature in `${CODEX_HOME:-~/.codex}/config.toml` when `codex` is available
+- Enable the native `hooks` feature in `${CODEX_HOME:-~/.codex}/config.toml` when `codex` is available
 - Seed `~/.config/humanize/config.json` with a Codex/OpenAI `bitlesson_model` when that key is not already set
 - Mark the install as `provider_mode: "codex-only"` when using `--target codex`
 - Use RLCR defaults: `codex exec` with `gpt-5.5:high`, `codex review` with `gpt-5.5:high`
 
-Requires Codex CLI `0.114.0` or newer for native hooks. Older Codex builds are not supported by the Codex install path.
+Requires Codex CLI `0.114.0` or newer for native hooks. The hooks feature was renamed to `hooks`; older Codex builds that still expose `codex_hooks` are not supported by the Codex install path.
 
 ## Verify
 
@@ -70,12 +70,12 @@ Installed files/directories:
 Verify native hooks:
 
 ```bash
-codex features list | rg codex_hooks
+codex features list | rg '^hooks\s'
 sed -n '1,220p' "${CODEX_HOME:-$HOME/.codex}/hooks.json"
 ```
 
 Expected:
-- `codex_hooks` is `true`
+- `hooks` is present in `codex features list`
 - `hooks.json` contains `loop-codex-stop-hook.sh`
 - `${XDG_CONFIG_HOME:-~/.config}/humanize/config.json` contains `bitlesson_model` set to a Codex/OpenAI model such as `gpt-5.5`
 - for `--target codex`, `${XDG_CONFIG_HOME:-~/.config}/humanize/config.json` also contains `provider_mode: "codex-only"`
@@ -110,6 +110,8 @@ ls -la "${CODEX_HOME:-$HOME/.codex}/skills/humanize/scripts"
 If native exit gating does not trigger:
 
 ```bash
-codex features enable codex_hooks
+codex features enable hooks
 sed -n '1,220p' "${CODEX_HOME:-$HOME/.codex}/hooks.json"
 ```
+
+If the installer reports that your config or installed Codex still uses `codex_hooks`, upgrade Codex first or change `${CODEX_HOME:-~/.codex}/config.toml` to `[features]\nhooks = true`.
diff --git a/hooks/loop-codex-stop-hook.sh b/hooks/loop-codex-stop-hook.sh
index 0c191d4..c15c300 100755
--- a/hooks/loop-codex-stop-hook.sh
+++ b/hooks/loop-codex-stop-hook.sh
@@ -1172,9 +1172,9 @@ mkdir -p "$CACHE_DIR"
 CODEX_DISABLE_HOOKS_ARGS=()
 _CODEX_FEATURE_CACHE="$CACHE_DIR/.codex-disable-hooks-supported"
 if [[ -f "$_CODEX_FEATURE_CACHE" ]]; then
-    [[ "$(cat "$_CODEX_FEATURE_CACHE")" == "yes" ]] && CODEX_DISABLE_HOOKS_ARGS=(--disable codex_hooks)
+    [[ "$(cat "$_CODEX_FEATURE_CACHE")" == "yes" ]] && CODEX_DISABLE_HOOKS_ARGS=(--disable hooks)
 elif codex --help 2>&1 | grep -q -- '--disable'; then
-    CODEX_DISABLE_HOOKS_ARGS=(--disable codex_hooks)
+    CODEX_DISABLE_HOOKS_ARGS=(--disable hooks)
     echo "yes" > "$_CODEX_FEATURE_CACHE" 2>/dev/null
 else
     echo "no" > "$_CODEX_FEATURE_CACHE" 2>/dev/null
diff --git a/scripts/bitlesson-select.sh b/scripts/bitlesson-select.sh
index fd19a44..1f781f5 100755
--- a/scripts/bitlesson-select.sh
+++ b/scripts/bitlesson-select.sh
@@ -193,7 +193,7 @@ run_selector() {
         local codex_exec_args=()
         # Probe whether the installed Codex CLI supports --disable flag
         if codex --help 2>&1 | grep -q -- '--disable'; then
-            codex_exec_args+=("--disable" "codex_hooks")
+            codex_exec_args+=("--disable" "hooks")
         fi
         # Probe for --skip-git-repo-check and --ephemeral support
         if codex exec --help 2>&1 | grep -q -- '--skip-git-repo-check'; then
diff --git a/scripts/install-codex-hooks.sh b/scripts/install-codex-hooks.sh
index 407fe66..87dcfc3 100755
--- a/scripts/install-codex-hooks.sh
+++ b/scripts/install-codex-hooks.sh
@@ -12,6 +12,7 @@ RUNTIME_ROOT="$CODEX_CONFIG_DIR/skills/humanize"
 DRY_RUN="false"
 ENABLE_FEATURE="true"
 HOOKS_TEMPLATE="$REPO_ROOT/config/codex-hooks.json"
+HOOK_FEATURE_ENABLED=""
 
 usage() {
     cat <<'EOF'
@@ -23,7 +24,7 @@ Usage:
 Options:
   --codex-config-dir PATH  Codex config dir (default: ${CODEX_HOME:-~/.codex})
   --runtime-root PATH      Installed Humanize runtime root (default: <codex-config-dir>/skills/humanize)
-  --skip-enable-feature    Do not run `codex features enable codex_hooks`
+  --skip-enable-feature    Do not run `codex features enable hooks`
   --dry-run                Print actions without writing
   -h, --help               Show help
 EOF
@@ -72,14 +73,40 @@ done
 
 HOOKS_FILE="$CODEX_CONFIG_DIR/hooks.json"
 
-require_codex_hooks_support() {
+config_uses_legacy_codex_hooks() {
+    local config_file="$CODEX_CONFIG_DIR/config.toml"
+
+    [[ -f "$config_file" ]] || return 1
+
+    grep -Eq '^[[:space:]]*(features\.)?codex_hooks[[:space:]]*=' "$config_file"
+}
+
+require_native_hooks_support() {
     if ! command -v codex >/dev/null 2>&1; then
         die "Codex CLI with native hooks support is required. Install Codex 0.114.0+ first."
     fi
 
-    if ! codex features list 2>/dev/null | grep -qE '^codex_hooks[[:space:]]'; then
-        die "Installed Codex CLI does not expose the codex_hooks feature. Humanize Codex install requires Codex 0.114.0+."
+    if config_uses_legacy_codex_hooks; then
+        die "Codex config uses the legacy feature key 'codex_hooks'. Current Codex uses 'hooks'. Update $CODEX_CONFIG_DIR/config.toml to use 'hooks = true' under [features], or upgrade Codex if 'codex features list' does not show 'hooks'."
+    fi
+
+    local features
+    local line
+    features="$(CODEX_HOME="$CODEX_CONFIG_DIR" codex features list 2>/dev/null)" || {
+        die "failed to inspect Codex features. Humanize Codex install requires the native 'hooks' feature."
+    }
+
+    line="$(printf '%s\n' "$features" | awk '$1 == "hooks" { print; exit }')"
+    if [[ -n "$line" ]]; then
+        HOOK_FEATURE_ENABLED="$(awk '{ print $NF }' <<<"$line")"
+        return 0
+    fi
+
+    if printf '%s\n' "$features" | awk '$1 == "codex_hooks" { found = 1 } END { exit found ? 0 : 1 }'; then
+        die "Installed Codex exposes only the legacy 'codex_hooks' feature. Humanize now requires the renamed 'hooks' feature. Upgrade Codex, then rerun the installer."
     fi
+
+    die "Installed Codex CLI does not expose the native 'hooks' feature. Upgrade Codex, then rerun the installer."
 }
 
 merge_hooks_json() {
@@ -177,10 +204,15 @@ enable_feature() {
 
     [[ "$ENABLE_FEATURE" == "true" ]] || return 0
 
-    if CODEX_HOME="$config_dir" codex features enable codex_hooks >/dev/null 2>&1; then
-        log "enabled codex_hooks feature in $config_dir/config.toml"
+    if [[ "$HOOK_FEATURE_ENABLED" == "true" ]]; then
+        log "native hooks feature already enabled in $config_dir/config.toml"
+        return 0
+    fi
+
+    if CODEX_HOME="$config_dir" codex features enable hooks >/dev/null 2>&1; then
+        log "enabled hooks feature in $config_dir/config.toml"
     else
-        die "failed to enable codex_hooks feature automatically in $config_dir/config.toml"
+        die "failed to enable hooks feature automatically in $config_dir/config.toml"
     fi
 }
 
@@ -188,12 +220,12 @@ log "codex config dir: $CODEX_CONFIG_DIR"
 log "runtime root: $RUNTIME_ROOT"
 log "hooks file: $HOOKS_FILE"
 
-require_codex_hooks_support
+require_native_hooks_support
 
 if [[ "$DRY_RUN" == "true" ]]; then
     log "DRY-RUN merge $HOOKS_TEMPLATE -> $HOOKS_FILE"
     if [[ "$ENABLE_FEATURE" == "true" ]]; then
-        log "DRY-RUN enable codex_hooks feature in $CODEX_CONFIG_DIR/config.toml"
+        log "DRY-RUN enable hooks feature in $CODEX_CONFIG_DIR/config.toml"
     fi
     exit 0
 fi
diff --git a/tests/run-all-tests.sh b/tests/run-all-tests.sh
index 169537a..00000ad 100755
--- a/tests/run-all-tests.sh
+++ b/tests/run-all-tests.sh
@@ -133,6 +133,12 @@ ZSH_TESTS=(
     "test-zsh-monitor-safety.sh"
 )
 
+# Signal-heavy runtime tests are more stable when they run after the
+# parallel batch finishes.
+SERIAL_TESTS=(
+    "test-monitor-runtime.sh"
+)
+
 # Temp directory for per-suite output files
 OUTPUT_DIR=$(mktemp -d)
 trap "rm -rf $OUTPUT_DIR" EXIT
@@ -161,6 +167,16 @@ needs_zsh() {
     return 1
 }
 
+needs_serial() {
+    local suite="$1"
+    for serial_test in "${SERIAL_TESTS[@]}"; do
+        if [[ "$suite" == "$serial_test" ]]; then
+            return 0
+        fi
+    done
+    return 1
+}
+
 # Format milliseconds as human-readable duration
 format_ms() {
     local ms="$1"
@@ -169,10 +185,79 @@ format_ms() {
     echo "${s}.${frac}s"
 }
 
-# Launch all test suites in parallel
+run_suite_capture() {
+    local suite="$1"
+    local out_file="$2"
+    local exit_file="$3"
+    local time_file="$4"
+    local suite_path="$SCRIPT_DIR/$suite"
+
+    if needs_zsh "$suite"; then
+        (
+            t_start=$(date +%s%3N)
+            zsh "$suite_path" >"$out_file" 2>&1
+            echo $? >"$exit_file"
+            echo $(( $(date +%s%3N) - t_start )) >"$time_file"
+        )
+    else
+        (
+            t_start=$(date +%s%3N)
+            "$suite_path" >"$out_file" 2>&1
+            echo $? >"$exit_file"
+            echo $(( $(date +%s%3N) - t_start )) >"$time_file"
+        )
+    fi
+}
+
+collect_suite_result() {
+    local suite="$1"
+    local safe_name="$2"
+    local out_file="$3"
+    local exit_file="$4"
+    local time_file="$5"
+    local exit_code
+    local output
+    local elapsed_ms
+    local elapsed_display
+    local output_stripped
+    local passed
+    local failed
+    local line
+    local zsh_label
+
+    exit_code=$(cat "$exit_file" 2>/dev/null || echo "1")
+    output=$(cat "$out_file" 2>/dev/null || echo "")
+    elapsed_ms=$(cat "$time_file" 2>/dev/null || echo "0")
+    elapsed_display=$(format_ms "$elapsed_ms")
+
+    # Strip ANSI escape codes and extract pass/fail counts
+    output_stripped=$(echo "$output" | sed "s/${esc}\\[[0-9;]*m//g")
+    passed=$(echo "$output_stripped" | grep -oE 'Passed:[[:space:]]*[0-9]+' | grep -oE '[0-9]+$' | tail -1 || echo "0")
+    failed=$(echo "$output_stripped" | grep -oE 'Failed:[[:space:]]*[0-9]+' | grep -oE '[0-9]+$' | tail -1 || echo "0")
+
+    TOTAL_PASSED=$((TOTAL_PASSED + passed))
+    TOTAL_FAILED=$((TOTAL_FAILED + failed))
+
+    if [[ $exit_code -ne 0 ]] || [[ "$failed" -gt 0 ]]; then
+        FAILED_SUITES+=("$suite")
+        line=$(echo -e "${RED}FAILED${NC}: $suite (exit code: $exit_code, failed: $failed, ${elapsed_display})")
+        printf '%d\t%s\n' "$elapsed_ms" "$line" >> "$SORT_FILE"
+        # Preserve the full suite log so CI surfaces the exact failing assertion.
+        printf '%s\n' "$output" > "$OUTPUT_DIR/${safe_name}.detail"
+    else
+        zsh_label=""
+        needs_zsh "$suite" && zsh_label=" (zsh)"
+        line=$(echo -e "${GREEN}PASSED${NC}: $suite${zsh_label} ($passed tests, ${elapsed_display})")
+        printf '%d\t%s\n' "$elapsed_ms" "$line" >> "$SORT_FILE"
+    fi
+}
+
+# Launch all test suites in parallel, except signal-heavy runtime tests which
+# run serially after the parallel batch finishes.
 declare -A PIDS          # suite -> PID
 declare -A SKIPPED       # suite -> reason
 ACTIVE_PIDS=()
+SERIAL_SUITES=()
 
 for suite in "${TEST_SUITES[@]}"; do
     suite_path="$SCRIPT_DIR/$suite"
@@ -186,25 +271,21 @@ for suite in "${TEST_SUITES[@]}"; do
         continue
     fi
 
+    if needs_serial "$suite"; then
+        SERIAL_SUITES+=("$suite")
+        continue
+    fi
+
     if needs_zsh "$suite"; then
         if ! command -v zsh &>/dev/null; then
             SKIPPED["$suite"]="zsh not available"
             continue
         fi
-        (
-            t_start=$(date +%s%3N)
-            zsh "$suite_path" >"$out_file" 2>&1
-            echo $? >"$exit_file"
-            echo $(( $(date +%s%3N) - t_start )) >"$time_file"
-        ) &
-    else
-        (
-            t_start=$(date +%s%3N)
-            "$suite_path" >"$out_file" 2>&1
-            echo $? >"$exit_file"
-            echo $(( $(date +%s%3N) - t_start )) >"$time_file"
-        ) &
     fi
+
+    (
+        run_suite_capture "$suite" "$out_file" "$exit_file" "$time_file"
+    ) &
     PIDS["$suite"]=$!
     ACTIVE_PIDS+=("${PIDS[$suite]}")
 
@@ -228,7 +309,7 @@ for suite in "${TEST_SUITES[@]}"; do
     done
 done
 
-# Wait for all and collect results
+# Wait for parallel suites and collect results.
 TOTAL_PASSED=0
 TOTAL_FAILED=0
 FAILED_SUITES=()
@@ -239,6 +320,7 @@ SORT_FILE="$OUTPUT_DIR/sortable.txt"
 esc=$'\033'
 for suite in "${TEST_SUITES[@]}"; do
     [[ -n "${SKIPPED[$suite]+x}" ]] && continue
+    [[ " ${SERIAL_SUITES[*]} " == *" $suite "* ]] && continue
 
     pid="${PIDS[$suite]}"
     wait "$pid" 2>/dev/null
@@ -247,32 +329,18 @@ for suite in "${TEST_SUITES[@]}"; do
     out_file="$OUTPUT_DIR/${safe_name}.out"
     exit_file="$OUTPUT_DIR/${safe_name}.exit"
     time_file="$OUTPUT_DIR/${safe_name}.time"
+    collect_suite_result "$suite" "$safe_name" "$out_file" "$exit_file" "$time_file"
+done
 
-    exit_code=$(cat "$exit_file" 2>/dev/null || echo "1")
-    output=$(cat "$out_file" 2>/dev/null || echo "")
-    elapsed_ms=$(cat "$time_file" 2>/dev/null || echo "0")
-    elapsed_display=$(format_ms "$elapsed_ms")
-
-    # Strip ANSI escape codes and extract pass/fail counts
-    output_stripped=$(echo "$output" | sed "s/${esc}\\[[0-9;]*m//g")
-    passed=$(echo "$output_stripped" | grep -oE 'Passed:[[:space:]]*[0-9]+' | grep -oE '[0-9]+$' | tail -1 || echo "0")
-    failed=$(echo "$output_stripped" | grep -oE 'Failed:[[:space:]]*[0-9]+' | grep -oE '[0-9]+$' | tail -1 || echo "0")
-
-    TOTAL_PASSED=$((TOTAL_PASSED + passed))
-    TOTAL_FAILED=$((TOTAL_FAILED + failed))
+# Run serial suites after the parallel batch finishes.
+for suite in "${SERIAL_SUITES[@]}"; do
+    safe_name="$(echo "$suite" | tr '/' '_')"
+    out_file="$OUTPUT_DIR/${safe_name}.out"
+    exit_file="$OUTPUT_DIR/${safe_name}.exit"
+    time_file="$OUTPUT_DIR/${safe_name}.time"
 
-    if [[ $exit_code -ne 0 ]] || [[ "$failed" -gt 0 ]]; then
-        FAILED_SUITES+=("$suite")
-        line=$(echo -e "${RED}FAILED${NC}: $suite (exit code: $exit_code, failed: $failed, ${elapsed_display})")
-        printf '%d\t%s\n' "$elapsed_ms" "$line" >> "$SORT_FILE"
-        # Preserve the full suite log so CI surfaces the exact failing assertion.
-        printf '%s\n' "$output" > "$OUTPUT_DIR/${safe_name}.detail"
-    else
-        zsh_label=""
-        needs_zsh "$suite" && zsh_label=" (zsh)"
-        line=$(echo -e "${GREEN}PASSED${NC}: $suite${zsh_label} ($passed tests, ${elapsed_display})")
-        printf '%d\t%s\n' "$elapsed_ms" "$line" >> "$SORT_FILE"
-    fi
+    run_suite_capture "$suite" "$out_file" "$exit_file" "$time_file"
+    collect_suite_result "$suite" "$safe_name" "$out_file" "$exit_file" "$time_file"
 done
 
 # Print skipped suites first
diff --git a/tests/test-bitlesson-select-routing.sh b/tests/test-bitlesson-select-routing.sh
index 68ecfa1..012f94e 100755
--- a/tests/test-bitlesson-select-routing.sh
+++ b/tests/test-bitlesson-select-routing.sh
@@ -8,7 +8,8 @@ source "$SCRIPT_DIR/test-helpers.sh"
 BITLESSON_SELECT="$PROJECT_ROOT/scripts/bitlesson-select.sh"
 # Keep PATH isolation strict in missing-binary tests to avoid picking up
 # real codex/claude from user-local directories (e.g. ~/.nvm, ~/.local/bin).
-SAFE_BASE_PATH="/usr/bin:/bin:/usr/sbin:/sbin"
+# On NixOS, the shell toolchain itself lives under /run/current-system/sw/bin.
+SAFE_BASE_PATH="/run/current-system/sw/bin:/usr/bin:/bin:/usr/sbin:/sbin"
 
 echo "=========================================="
 echo "Bitlesson Select Routing Tests"
@@ -481,7 +482,7 @@ captured_args="$(cat "$CAPTURE_ARGS")"
 if [[ $exit_code -eq 0 ]] \
     && echo "$stdout_out" | grep -q "BL-20260315-tracker-drift" \
     && echo "$captured_args" | grep -q -- '--disable' \
-    && echo "$captured_args" | grep -q -- 'codex_hooks' \
+    && echo "$captured_args" | grep -q -- 'hooks' \
     && echo "$captured_args" | grep -q -- '--skip-git-repo-check' \
     && echo "$captured_args" | grep -q -- '--ephemeral' \
     && echo "$captured_args" | grep -q -- 'read-only' \
diff --git a/tests/test-codex-hook-install.sh b/tests/test-codex-hook-install.sh
index da20fb9..60b4fcc 100755
--- a/tests/test-codex-hook-install.sh
+++ b/tests/test-codex-hook-install.sh
@@ -43,15 +43,15 @@ set -euo pipefail
 
 if [[ "${1:-}" == "features" && "${2:-}" == "list" ]]; then
     cat <<'LIST'
-codex_hooks                      under development  false
+hooks                            stable             false
 LIST
     exit 0
 fi
 
-if [[ "${1:-}" == "features" && "${2:-}" == "enable" && "${3:-}" == "codex_hooks" ]]; then
+if [[ "${1:-}" == "features" && "${2:-}" == "enable" && "${3:-}" == "hooks" ]]; then
     printf 'CODEX_HOME=%s\n' "${CODEX_HOME:-}" >> "${TEST_CODEX_FEATURE_LOG:?}"
     mkdir -p "${CODEX_HOME:?}"
-    : > "${CODEX_HOME}/.codex-hooks-enabled"
+    : > "${CODEX_HOME}/.hooks-enabled"
     exit 0
 fi
 
@@ -133,10 +133,10 @@ else
     fail "Codex install writes hooks.json" "$HOOKS_FILE exists" "missing"
 fi
 
-if [[ -f "$CODEX_HOME_DIR/.codex-hooks-enabled" ]]; then
-    pass "Codex install enables codex_hooks feature"
+if [[ -f "$CODEX_HOME_DIR/.hooks-enabled" ]]; then
+    pass "Codex install enables hooks feature"
 else
-    fail "Codex install enables codex_hooks feature" ".codex-hooks-enabled marker exists" "missing"
+    fail "Codex install enables hooks feature" ".hooks-enabled marker exists" "missing"
 fi
 
 if [[ -f "$HUMANIZE_USER_CONFIG" ]]; then
@@ -287,6 +287,83 @@ else
     fail "Codex feature enable runs on each Codex install/update" "2 log entries" "$(cat "$FEATURE_LOG")"
 fi
 
+LEGACY_CONFIG_HOME="$TEST_DIR/codex-home-legacy-config"
+mkdir -p "$LEGACY_CONFIG_HOME"
+cat > "$LEGACY_CONFIG_HOME/config.toml" <<'EOF'
+[features]
+codex_hooks = true
+EOF
+
+set +e
+PATH="$FAKE_BIN:$PATH" TEST_CODEX_FEATURE_LOG="$FEATURE_LOG" \
+    "$INSTALL_SCRIPT" \
+    --target codex \
+    --codex-config-dir "$LEGACY_CONFIG_HOME" \
+    --codex-skills-dir "$LEGACY_CONFIG_HOME/skills" \
+    > "$TEST_DIR/install-legacy-config.log" 2>&1
+LEGACY_CONFIG_EXIT=$?
+set -e
+
+if [[ "$LEGACY_CONFIG_EXIT" -ne 0 ]]; then
+    pass "Codex install rejects legacy codex_hooks config"
+else
+    fail "Codex install rejects legacy codex_hooks config" "non-zero exit" "exit 0"
+fi
+
+if grep -q "legacy feature key 'codex_hooks'" "$TEST_DIR/install-legacy-config.log" \
+    && grep -q "hooks = true" "$TEST_DIR/install-legacy-config.log"; then
+    pass "Legacy codex_hooks config failure explains hooks rename"
+else
+    fail "Legacy codex_hooks config failure explains hooks rename" \
+        "error mentioning legacy codex_hooks and hooks = true" \
+        "$(cat "$TEST_DIR/install-legacy-config.log")"
+fi
+
+LEGACY_ONLY_BIN="$TEST_DIR/bin-legacy-only"
+LEGACY_ONLY_HOME="$TEST_DIR/codex-home-legacy-only"
+mkdir -p "$LEGACY_ONLY_BIN" "$LEGACY_ONLY_HOME"
+
+cat > "$LEGACY_ONLY_BIN/codex" <<'EOF'
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [[ "${1:-}" == "features" && "${2:-}" == "list" ]]; then
+    cat <<'LIST'
+codex_hooks                      under development  false
+LIST
+    exit 0
+fi
+
+echo "unexpected fake codex invocation: $*" >&2
+exit 1
+EOF
+chmod +x "$LEGACY_ONLY_BIN/codex"
+
+set +e
+PATH="$LEGACY_ONLY_BIN:$PATH" \
+    "$INSTALL_SCRIPT" \
+    --target codex \
+    --codex-config-dir "$LEGACY_ONLY_HOME" \
+    --codex-skills-dir "$LEGACY_ONLY_HOME/skills" \
+    > "$TEST_DIR/install-legacy-only.log" 2>&1
+LEGACY_ONLY_EXIT=$?
+set -e
+
+if [[ "$LEGACY_ONLY_EXIT" -ne 0 ]]; then
+    pass "Codex install rejects Codex builds exposing only legacy codex_hooks"
+else
+    fail "Codex install rejects Codex builds exposing only legacy codex_hooks" "non-zero exit" "exit 0"
+fi
+
+if grep -q "legacy 'codex_hooks' feature" "$TEST_DIR/install-legacy-only.log" \
+    && grep -q "Upgrade Codex" "$TEST_DIR/install-legacy-only.log"; then
+    pass "Legacy-only feature failure asks user to upgrade Codex"
+else
+    fail "Legacy-only feature failure asks user to upgrade Codex" \
+        "error mentioning legacy codex_hooks and Upgrade Codex" \
+        "$(cat "$TEST_DIR/install-legacy-only.log")"
+fi
+
 UNSUPPORTED_BIN="$TEST_DIR/bin-unsupported"
 UNSUPPORTED_HOME="$TEST_DIR/codex-home-unsupported"
 mkdir -p "$UNSUPPORTED_BIN" "$UNSUPPORTED_HOME"
@@ -323,11 +400,12 @@ else
     fail "Codex install rejects builds without native hooks support" "non-zero exit" "exit 0"
 fi
 
-if grep -q "codex_hooks feature" "$TEST_DIR/install-unsupported.log"; then
-    pass "Unsupported Codex failure explains missing codex_hooks feature"
+if grep -q "native 'hooks' feature" "$TEST_DIR/install-unsupported.log" \
+    && grep -q "Upgrade Codex" "$TEST_DIR/install-unsupported.log"; then
+    pass "Unsupported Codex failure explains missing hooks feature"
 else
-    fail "Unsupported Codex failure explains missing codex_hooks feature" \
-        "error mentioning codex_hooks feature" \
+    fail "Unsupported Codex failure explains missing hooks feature" \
+        "error mentioning native hooks feature and Upgrade Codex" \
         "$(cat "$TEST_DIR/install-unsupported.log")"
 fi
 
diff --git a/tests/test-disable-nested-codex-hooks.sh b/tests/test-disable-nested-codex-hooks.sh
index c240ad6..3cbce63 100755
--- a/tests/test-disable-nested-codex-hooks.sh
+++ b/tests/test-disable-nested-codex-hooks.sh
@@ -77,7 +77,7 @@ if [[ "\$1" == "--help" ]]; then
 Usage: codex [OPTIONS] <COMMAND>
 
 Options:
-  --disable <HOOK>         Disable a specific Codex hook (e.g. codex_hooks)
+  --disable <HOOK>         Disable a specific Codex hook (e.g. hooks)
   --skip-git-repo-check    Skip git repo validation
 HELP
     exit 0
@@ -188,22 +188,22 @@ REPO_IMPL="$TEST_DIR/repo-impl"
 setup_repo "$REPO_IMPL"
 run_loop_hook "$REPO_IMPL" "$TEST_DIR/impl.args" "false"
 
-if grep -q -- 'exec --disable codex_hooks' "$TEST_DIR/impl.args"; then
-    pass "implementation-phase stop hook disables codex_hooks for codex exec"
+if grep -q -- 'exec --disable hooks' "$TEST_DIR/impl.args"; then
+    pass "implementation-phase stop hook disables hooks for codex exec"
 else
-    fail "implementation-phase stop hook disables codex_hooks for codex exec" \
-        "exec --disable codex_hooks" "$(cat "$TEST_DIR/impl.args" 2>/dev/null || echo missing)"
+    fail "implementation-phase stop hook disables hooks for codex exec" \
+        "exec --disable hooks" "$(cat "$TEST_DIR/impl.args" 2>/dev/null || echo missing)"
 fi
 
 REPO_REVIEW="$TEST_DIR/repo-review"
 setup_repo "$REPO_REVIEW"
 run_loop_hook "$REPO_REVIEW" "$TEST_DIR/review.args" "true"
 
-if grep -q -- 'review --disable codex_hooks' "$TEST_DIR/review.args"; then
-    pass "review-phase stop hook disables codex_hooks for codex review"
+if grep -q -- 'review --disable hooks' "$TEST_DIR/review.args"; then
+    pass "review-phase stop hook disables hooks for codex review"
 else
-    fail "review-phase stop hook disables codex_hooks for codex review" \
-        "review --disable codex_hooks" "$(cat "$TEST_DIR/review.args" 2>/dev/null || echo missing)"
+    fail "review-phase stop hook disables hooks for codex review" \
+        "review --disable hooks" "$(cat "$TEST_DIR/review.args" 2>/dev/null || echo missing)"
 fi
 
 echo ""
diff --git a/tests/test-monitor-runtime.sh b/tests/test-monitor-runtime.sh
index e146ada..dee3d43 100755
--- a/tests/test-monitor-runtime.sh
+++ b/tests/test-monitor-runtime.sh
@@ -354,8 +354,8 @@ trap '_cleanup' INT TERM
 ) &
 child_pid=$!
 
-# Wait for signal (up to 1 second)
-for i in {1..10}; do
+# Wait for signal (up to 5 seconds); parallel CI runners can be slow.
+for i in {1..50}; do
     sleep 0.1
     if [[ "$cleanup_triggered" == "true" ]]; then
         break
@@ -454,8 +454,8 @@ TRAPINT() {
 ) &
 child_pid=$!
 
-# Wait for signal (up to 1 second)
-for i in {1..10}; do
+# Wait for signal (up to 5 seconds); parallel CI runners can be slow.
+for i in {1..50}; do
     sleep 0.1
     if [[ "$cleanup_triggered" == "true" ]]; then
         break
diff --git a/tests/test-templates-comprehensive.sh b/tests/test-templates-comprehensive.sh
index d27dac4..aca988a 100755
--- a/tests/test-templates-comprehensive.sh
+++ b/tests/test-templates-comprehensive.sh
@@ -329,7 +329,7 @@ echo ""
 echo "Testing backslashes in values..."
 result=$(render_template "Code: {{CODE}}" "CODE=\$HOME\\npath")
 # Note: backslashes may be interpreted by awk
-if echo "$result" | grep -q "Code:"; then
+if grep -q "Code:" <<<"$result"; then
     pass "Backslashes in values (no crash)"
 else
     fail "Backslashes in values" "Code: ..." "$result"
@@ -338,7 +338,7 @@ fi
 echo ""
 echo "Testing quotes in values..."
 result=$(render_template "Quote: {{MSG}}" "MSG=He said \"hello\" and 'bye'")
-if echo "$result" | grep -q "Quote:"; then
+if grep -q "Quote:" <<<"$result"; then
     pass "Quotes in values"
 else
     fail "Quotes in values" "Quote: ..." "$result"
@@ -350,7 +350,7 @@ result=$(render_template "Message: {{MSG}}" "MSG=Hello World")
 if [[ "$result" == "Message: Hello World" ]]; then
     # CJK in variable value
     result2=$(render_template "CJK: {{CJK}}" "CJK=Chinese Text Here")
-    if echo "$result2" | grep -q "CJK:"; then
+    if grep -q "CJK:" <<<"$result2"; then
         pass "CJK characters handling"
     else
         fail "CJK characters handling" "CJK: ..." "$result2"
@@ -373,7 +373,7 @@ fi
 echo ""
 echo "Testing markdown formatting in values..."
 result=$(render_template "Formatted: {{TEXT}}" "TEXT=**bold** and _italic_ and \`code\`")
-if echo "$result" | grep -q "Formatted:"; then
+if grep -q "Formatted:" <<<"$result"; then
     pass "Markdown formatting in values"
 else
     fail "Markdown formatting in values" "Formatted: ..." "$result"
@@ -395,7 +395,7 @@ multiline_value="Line 1
 Line 2
 Line 3"
 result=$(render_template "Content: {{CONTENT}}" "CONTENT=$multiline_value")
-if echo "$result" | grep -q "Content:"; then
+if grep -q "Content:" <<<"$result"; then
     pass "Multiline values (no crash)"
 else
     fail "Multiline values" "Content: ..." "$result"
@@ -446,7 +446,7 @@ echo ""
 echo "Testing load_and_render_safe with missing template..."
 fallback="Fallback: {{VAR}}"
 result=$(load_and_render_safe "$TEMPLATE_DIR" "non-existing-file.md" "$fallback" "VAR=test")
-if echo "$result" | grep -q "Fallback: test"; then
+if grep -q "Fallback: test" <<<"$result"; then
     pass "Fallback used for missing template"
 else
     fail "Fallback used for missing template" "Fallback: test" "$result"
@@ -456,7 +456,7 @@ echo ""
 echo "Testing load_and_render_safe with existing template..."
 fallback="This should NOT appear"
 result=$(load_and_render_safe "$TEMPLATE_DIR" "block/git-push.md" "$fallback")
-if echo "$result" | grep -q "Git Push Blocked" && ! echo "$result" | grep -q "should NOT appear"; then
+if grep -q "Git Push Blocked" <<<"$result" && ! grep -q "should NOT appear" <<<"$result"; then
     pass "Real template used when available"
 else
     fail "Real template used when available" "Git Push Blocked" "$result"
@@ -503,10 +503,10 @@ result=$(load_and_render "$TEMPLATE_DIR" "block/wrong-round-number.md" \
     "CURRENT_ROUND=5" \
     "CORRECT_PATH=/tmp/round-5-summary.md")
 
-if echo "$result" | grep -q "Wrong Round Number" && \
-   echo "$result" | grep -q "round-3-summary" && \
-   echo "$result" | grep -q "current round is \*\*5\*\*" && \
-   echo "$result" | grep -q "/tmp/round-5-summary.md"; then
+if grep -q "Wrong Round Number" <<<"$result" && \
+   grep -q "round-3-summary" <<<"$result" && \
+   grep -q "current round is \*\*5\*\*" <<<"$result" && \
+   grep -q "/tmp/round-5-summary.md" <<<"$result"; then
     pass "Real template rendering with all variables"
 else
     fail "Real template rendering with all variables"
@@ -519,9 +519,9 @@ result=$(load_and_render "$TEMPLATE_DIR" "block/unpushed-commits.md" \
     "AHEAD_COUNT=3" \
     "CURRENT_BRANCH=feature-branch")
 
-if echo "$result" | grep -q "Unpushed Commits" && \
-   echo "$result" | grep -q "3 unpushed" && \
-   echo "$result" | grep -q "feature-branch"; then
+if grep -q "Unpushed Commits" <<<"$result" && \
+   grep -q "3 unpushed" <<<"$result" && \
+   grep -q "feature-branch" <<<"$result"; then
     pass "Real template: unpushed-commits.md"
 else
     fail "Real template: unpushed-commits.md"
@@ -532,8 +532,8 @@ echo "Testing real template: codex/goal-tracker-update-section.md..."
 result=$(load_and_render "$TEMPLATE_DIR" "codex/goal-tracker-update-section.md" \
     "GOAL_TRACKER_FILE=.humanize/rlcr/20240101/goal-tracker.md")
 
-if echo "$result" | grep -q "Goal Tracker Update Requests" && \
-   echo "$result" | grep -q ".humanize/rlcr/20240101/goal-tracker.md"; then
+if grep -q "Goal Tracker Update Requests" <<<"$result" && \
+   grep -q ".humanize/rlcr/20240101/goal-tracker.md" <<<"$result"; then
     pass "Real template: goal-tracker-update-section.md"
 else
     fail "Real template: goal-tracker-update-section.md"