diff --git a/.agents/skills/gstack-cso/SKILL.md b/.agents/skills/gstack-cso/SKILL.md
index 2913901d..132af401 100644
--- a/.agents/skills/gstack-cso/SKILL.md
+++ b/.agents/skills/gstack-cso/SKILL.md
@@ -12,23 +12,28 @@ description: |
 ## Preamble (run first)
 
 ```bash
-_UPD=$(~/.codex/skills/gstack/bin/gstack-update-check 2>/dev/null || .agents/skills/gstack/bin/gstack-update-check 2>/dev/null || true)
+_ROOT=$(git rev-parse --show-toplevel 2>/dev/null)
+GSTACK_ROOT="$HOME/.codex/skills/gstack"
+[ -n "$_ROOT" ] && [ -d "$_ROOT/.agents/skills/gstack" ] && GSTACK_ROOT="$_ROOT/.agents/skills/gstack"
+GSTACK_BIN="$GSTACK_ROOT/bin"
+GSTACK_BROWSE="$GSTACK_ROOT/browse/dist"
+_UPD=$($GSTACK_BIN/gstack-update-check 2>/dev/null || .agents/skills/gstack/bin/gstack-update-check 2>/dev/null || true)
 [ -n "$_UPD" ] && echo "$_UPD" || true
 mkdir -p ~/.gstack/sessions
 touch ~/.gstack/sessions/"$PPID"
 _SESSIONS=$(find ~/.gstack/sessions -mmin -120 -type f 2>/dev/null | wc -l | tr -d ' ')
 find ~/.gstack/sessions -mmin +120 -type f -delete 2>/dev/null || true
-_CONTRIB=$(~/.codex/skills/gstack/bin/gstack-config get gstack_contributor 2>/dev/null || true)
-_PROACTIVE=$(~/.codex/skills/gstack/bin/gstack-config get proactive 2>/dev/null || echo "true")
+_CONTRIB=$($GSTACK_BIN/gstack-config get gstack_contributor 2>/dev/null || true)
+_PROACTIVE=$($GSTACK_BIN/gstack-config get proactive 2>/dev/null || echo "true")
 _BRANCH=$(git branch --show-current 2>/dev/null || echo "unknown")
 echo "BRANCH: $_BRANCH"
 echo "PROACTIVE: $_PROACTIVE"
-source <(~/.codex/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
+source <($GSTACK_BIN/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
-_TEL=$(~/.codex/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
+_TEL=$($GSTACK_BIN/gstack-config get telemetry 2>/dev/null || true)
 _TEL_PROMPTED=$([ -f ~/.gstack/.telemetry-prompted ] && echo "yes" || echo "no")
 _TEL_START=$(date +%s)
 _SESSION_ID="$$-$(date +%s)"
@@ -36,13 +41,13 @@ echo "TELEMETRY: ${_TEL:-off}"
 echo "TEL_PROMPTED: $_TEL_PROMPTED"
 mkdir -p ~/.gstack/analytics
 echo '{"skill":"cso","ts":"'$(date -u +%Y-%m-%dT%H:%M:%SZ)'","repo":"'$(basename "$(git rev-parse --show-toplevel 2>/dev/null)" 2>/dev/null || echo "unknown")'"}'  >> ~/.gstack/analytics/skill-usage.jsonl 2>/dev/null || true
-for _PF in ~/.gstack/analytics/.pending-*; do [ -f "$_PF" ] && ~/.codex/skills/gstack/bin/gstack-telemetry-log --event-type skill_run --skill _pending_finalize --outcome unknown --session-id "$_SESSION_ID" 2>/dev/null || true; break; done
+for _PF in ~/.gstack/analytics/.pending-*; do [ -f "$_PF" ] && $GSTACK_BIN/gstack-telemetry-log --event-type skill_run --skill _pending_finalize --outcome unknown --session-id "$_SESSION_ID" 2>/dev/null || true; break; done
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills — only invoke
 them when the user explicitly asks. The user opted out of proactive suggestions.
 
-If output shows `UPGRADE_AVAILABLE <old> <new>`: read `~/.codex/skills/gstack/gstack-upgrade/SKILL.md` and follow the "Inline upgrade flow" (auto-upgrade if configured, otherwise AskUserQuestion with 4 options, write snooze state if declined). If `JUST_UPGRADED <from> <to>`: tell user "Running gstack v{to} (just updated!)" and continue.
+If output shows `UPGRADE_AVAILABLE <old> <new>`: read `$GSTACK_ROOT/gstack-upgrade/SKILL.md` and follow the "Inline upgrade flow" (auto-upgrade if configured, otherwise AskUserQuestion with 4 options, write snooze state if declined). If `JUST_UPGRADED <from> <to>`: tell user "Running gstack v{to} (just updated!)" and continue.
 
 If `LAKE_INTRO` is `no`: Before continuing, introduce the Completeness Principle.
 Tell the user: "gstack follows the **Boil the Lake** principle — always do the complete
@@ -68,7 +73,7 @@ Options:
 - A) Help gstack get better! (recommended)
 - B) No thanks
 
-If A: run `~/.codex/skills/gstack/bin/gstack-config set telemetry community`
+If A: run `$GSTACK_BIN/gstack-config set telemetry community`
 
 If B: ask a follow-up AskUserQuestion:
 
@@ -79,8 +84,8 @@ Options:
 - A) Sure, anonymous is fine
 - B) No thanks, fully off
 
-If B→A: run `~/.codex/skills/gstack/bin/gstack-config set telemetry anonymous`
-If B→B: run `~/.codex/skills/gstack/bin/gstack-config set telemetry off`
+If B→A: run `$GSTACK_BIN/gstack-config set telemetry anonymous`
+If B→B: run `$GSTACK_BIN/gstack-config set telemetry off`
 
 Always run:
 ```bash
@@ -140,7 +145,7 @@ Never let a noticed issue silently pass. The whole point is proactive communicat
 
 ## Search Before Building
 
-Before building infrastructure, unfamiliar patterns, or anything the runtime might have a built-in — **search first.** Read `~/.codex/skills/gstack/ETHOS.md` for the full philosophy.
+Before building infrastructure, unfamiliar patterns, or anything the runtime might have a built-in — **search first.** Read `$GSTACK_ROOT/ETHOS.md` for the full philosophy.
 
 **Three layers of knowledge:**
 - **Layer 1** (tried and true — in distribution). Don't reinvent the wheel. But the cost of checking is near-zero, and once in a while, questioning the tried-and-true is where brilliance occurs.
@@ -238,7 +243,7 @@ Run this bash:
 _TEL_END=$(date +%s)
 _TEL_DUR=$(( _TEL_END - _TEL_START ))
 rm -f ~/.gstack/analytics/.pending-"$_SESSION_ID" 2>/dev/null || true
-~/.codex/skills/gstack/bin/gstack-telemetry-log \
+$GSTACK_ROOT/bin/gstack-telemetry-log \
   --skill "SKILL_NAME" --duration "$_TEL_DUR" --outcome "OUTCOME" \
   --used-browse "USED_BROWSE" --session-id "$_SESSION_ID" 2>/dev/null &
 ```
diff --git a/gstack-upgrade/SKILL.md b/gstack-upgrade/SKILL.md
index 6dcc1f7c..f97f11fb 100644
--- a/gstack-upgrade/SKILL.md
+++ b/gstack-upgrade/SKILL.md
@@ -79,9 +79,15 @@ Continue with the current skill.
 if [ -d "$HOME/.claude/skills/gstack/.git" ]; then
   INSTALL_TYPE="global-git"
   INSTALL_DIR="$HOME/.claude/skills/gstack"
+elif [ -d "$HOME/.gstack/repos/gstack/.git" ]; then
+  INSTALL_TYPE="global-git"
+  INSTALL_DIR="$HOME/.gstack/repos/gstack"
 elif [ -d ".claude/skills/gstack/.git" ]; then
   INSTALL_TYPE="local-git"
   INSTALL_DIR=".claude/skills/gstack"
+elif [ -d ".agents/skills/gstack/.git" ]; then
+  INSTALL_TYPE="local-git"
+  INSTALL_DIR=".agents/skills/gstack"
 elif [ -d ".claude/skills/gstack" ]; then
   INSTALL_TYPE="vendored"
   INSTALL_DIR=".claude/skills/gstack"
diff --git a/gstack-upgrade/SKILL.md.tmpl b/gstack-upgrade/SKILL.md.tmpl
index 1d49cd1b..ac25894b 100644
--- a/gstack-upgrade/SKILL.md.tmpl
+++ b/gstack-upgrade/SKILL.md.tmpl
@@ -77,9 +77,15 @@ Continue with the current skill.
 if [ -d "$HOME/.claude/skills/gstack/.git" ]; then
   INSTALL_TYPE="global-git"
   INSTALL_DIR="$HOME/.claude/skills/gstack"
+elif [ -d "$HOME/.gstack/repos/gstack/.git" ]; then
+  INSTALL_TYPE="global-git"
+  INSTALL_DIR="$HOME/.gstack/repos/gstack"
 elif [ -d ".claude/skills/gstack/.git" ]; then
   INSTALL_TYPE="local-git"
   INSTALL_DIR=".claude/skills/gstack"
+elif [ -d ".agents/skills/gstack/.git" ]; then
+  INSTALL_TYPE="local-git"
+  INSTALL_DIR=".agents/skills/gstack"
 elif [ -d ".claude/skills/gstack" ]; then
   INSTALL_TYPE="vendored"
   INSTALL_DIR=".claude/skills/gstack"
diff --git a/review/SKILL.md b/review/SKILL.md
index 5bbf79c3..2048435a 100644
--- a/review/SKILL.md
+++ b/review/SKILL.md
@@ -745,7 +745,7 @@ TMPERR_ADV=$(mktemp /tmp/codex-adv-XXXXXXXX)
 codex exec "Review the changes on this branch against the base branch. Run git diff origin/<base> to see the diff. Your job is to find ways this code will fail in production. Think like an attacker and a chaos engineer. Find edge cases, race conditions, security holes, resource leaks, failure modes, and silent data corruption paths. Be adversarial. Be thorough. No compliments — just the problems." -s read-only -c 'model_reasoning_effort="xhigh"' --enable web_search_cached 2>"$TMPERR_ADV"
 ```
 
-Use a 5-minute timeout (`timeout: 300000`). After the command completes, read stderr:
+Set the Bash tool's `timeout` parameter to `300000` (5 minutes). Do NOT use the `timeout` shell command — it doesn't exist on macOS. After the command completes, read stderr:
 ```bash
 cat "$TMPERR_ADV"
 ```
@@ -790,7 +790,7 @@ TMPERR=$(mktemp /tmp/codex-review-XXXXXXXX)
 codex review --base <base> -c 'model_reasoning_effort="xhigh"' --enable web_search_cached 2>"$TMPERR"
 ```
 
-Use a 5-minute timeout. Present output under `CODEX SAYS (code review):` header.
+Set the Bash tool's `timeout` parameter to `300000` (5 minutes). Do NOT use the `timeout` shell command — it doesn't exist on macOS. Present output under `CODEX SAYS (code review):` header.
 Check for `[P1]` markers: found → `GATE: FAIL`, not found → `GATE: PASS`.
 
 If GATE is FAIL, use AskUserQuestion:
diff --git a/scripts/gen-skill-docs.ts b/scripts/gen-skill-docs.ts
index 3822f961..5062d520 100644
--- a/scripts/gen-skill-docs.ts
+++ b/scripts/gen-skill-docs.ts
@@ -2044,7 +2044,7 @@ TMPERR_ADV=$(mktemp /tmp/codex-adv-XXXXXXXX)
 codex exec "Review the changes on this branch against the base branch. Run git diff origin/<base> to see the diff. Your job is to find ways this code will fail in production. Think like an attacker and a chaos engineer. Find edge cases, race conditions, security holes, resource leaks, failure modes, and silent data corruption paths. Be adversarial. Be thorough. No compliments — just the problems." -s read-only -c 'model_reasoning_effort="xhigh"' --enable web_search_cached 2>"$TMPERR_ADV"
 \`\`\`
 
-Use a 5-minute timeout (\`timeout: 300000\`). After the command completes, read stderr:
+Set the Bash tool's \`timeout\` parameter to \`300000\` (5 minutes). Do NOT use the \`timeout\` shell command — it doesn't exist on macOS. After the command completes, read stderr:
 \`\`\`bash
 cat "$TMPERR_ADV"
 \`\`\`
@@ -2089,7 +2089,7 @@ TMPERR=$(mktemp /tmp/codex-review-XXXXXXXX)
 codex review --base <base> -c 'model_reasoning_effort="xhigh"' --enable web_search_cached 2>"$TMPERR"
 \`\`\`
 
-Use a 5-minute timeout. Present output under \`CODEX SAYS (code review):\` header.
+Set the Bash tool's \`timeout\` parameter to \`300000\` (5 minutes). Do NOT use the \`timeout\` shell command — it doesn't exist on macOS. Present output under \`CODEX SAYS (code review):\` header.
 Check for \`[P1]\` markers: found → \`GATE: FAIL\`, not found → \`GATE: PASS\`.
 
 If GATE is FAIL, use AskUserQuestion:
diff --git a/setup b/setup
index 3cb47d38..75dbf731 100755
--- a/setup
+++ b/setup
@@ -24,7 +24,7 @@ esac
 HOST="claude"
 while [ $# -gt 0 ]; do
   case "$1" in
-    --host) HOST="$2"; shift 2 ;;
+    --host) [ -z "$2" ] && echo "Missing value for --host (expected claude, codex, kiro, or auto)" >&2 && exit 1; HOST="$2"; shift 2 ;;
     --host=*) HOST="${1#--host=}"; shift ;;
     *) shift ;;
   esac
@@ -293,6 +293,10 @@ create_codex_runtime_root() {
 
   if [ -L "$codex_gstack" ]; then
     rm -f "$codex_gstack"
+  elif [ -d "$codex_gstack" ] && [ "$codex_gstack" != "$gstack_dir" ]; then
+    # Old direct installs left a real directory here with stale source skills.
+    # Remove it so we start fresh with only the minimal runtime assets.
+    rm -rf "$codex_gstack"
   fi
 
   mkdir -p "$codex_gstack" "$codex_gstack/browse" "$codex_gstack/gstack-upgrade" "$codex_gstack/review"
@@ -318,6 +322,10 @@ create_codex_runtime_root() {
       ln -snf "$gstack_dir/review/$f" "$codex_gstack/review/$f"
     fi
   done
+  # ETHOS.md — referenced by "Search Before Building" in all skill preambles
+  if [ -f "$gstack_dir/ETHOS.md" ]; then
+    ln -snf "$gstack_dir/ETHOS.md" "$codex_gstack/ETHOS.md"
+  fi
 }
 
 # 4. Install for Claude (default)
@@ -348,7 +356,11 @@ if [ "$INSTALL_CODEX" -eq 1 ]; then
   fi
   mkdir -p "$CODEX_SKILLS"
 
-  create_codex_runtime_root "$SOURCE_GSTACK_DIR" "$CODEX_GSTACK"
+  # Skip runtime root creation for repo-local installs — the checkout IS the runtime root.
+  # create_codex_runtime_root would create self-referential symlinks (bin → bin, etc.).
+  if [ "$CODEX_REPO_LOCAL" -eq 0 ]; then
+    create_codex_runtime_root "$SOURCE_GSTACK_DIR" "$CODEX_GSTACK"
+  fi
   # Install generated Codex-format skills (not Claude source dirs)
   link_codex_skill_dirs "$SOURCE_GSTACK_DIR" "$CODEX_SKILLS"
 
@@ -367,9 +379,24 @@ if [ "$INSTALL_KIRO" -eq 1 ]; then
   KIRO_GSTACK="$KIRO_SKILLS/gstack"
   # Remove old whole-dir symlink from previous installs
   [ -L "$KIRO_GSTACK" ] && rm -f "$KIRO_GSTACK"
-  mkdir -p "$KIRO_GSTACK"
+  mkdir -p "$KIRO_GSTACK" "$KIRO_GSTACK/browse" "$KIRO_GSTACK/gstack-upgrade" "$KIRO_GSTACK/review"
   ln -snf "$SOURCE_GSTACK_DIR/bin" "$KIRO_GSTACK/bin"
-  ln -snf "$SOURCE_GSTACK_DIR/browse" "$KIRO_GSTACK/browse"
+  ln -snf "$SOURCE_GSTACK_DIR/browse/dist" "$KIRO_GSTACK/browse/dist"
+  ln -snf "$SOURCE_GSTACK_DIR/browse/bin" "$KIRO_GSTACK/browse/bin"
+  # ETHOS.md — referenced by "Search Before Building" in all skill preambles
+  if [ -f "$SOURCE_GSTACK_DIR/ETHOS.md" ]; then
+    ln -snf "$SOURCE_GSTACK_DIR/ETHOS.md" "$KIRO_GSTACK/ETHOS.md"
+  fi
+  # gstack-upgrade skill
+  if [ -f "$AGENTS_DIR/gstack-upgrade/SKILL.md" ]; then
+    ln -snf "$AGENTS_DIR/gstack-upgrade/SKILL.md" "$KIRO_GSTACK/gstack-upgrade/SKILL.md"
+  fi
+  # Review runtime assets (individual files, not whole dir)
+  for f in checklist.md design-checklist.md greptile-triage.md TODOS-format.md; do
+    if [ -f "$SOURCE_GSTACK_DIR/review/$f" ]; then
+      ln -snf "$SOURCE_GSTACK_DIR/review/$f" "$KIRO_GSTACK/review/$f"
+    fi
+  done
 
   # Rewrite root SKILL.md paths for Kiro
   sed -e "s|~/.claude/skills/gstack|~/.kiro/skills/gstack|g" \
@@ -385,10 +412,11 @@ if [ "$INSTALL_KIRO" -eq 1 ]; then
       skill_name="$(basename "$skill_dir")"
       target_dir="$KIRO_SKILLS/$skill_name"
       mkdir -p "$target_dir"
-      sed -e "s|~/.codex/skills/gstack|~/.kiro/skills/gstack|g" \
+      # Generated Codex skills use $HOME/.codex (not ~/), plus $GSTACK_ROOT variables.
+      # Rewrite the default GSTACK_ROOT value and any remaining literal paths.
+      sed -e 's|\$HOME/.codex/skills/gstack|$HOME/.kiro/skills/gstack|g' \
+          -e "s|~/.codex/skills/gstack|~/.kiro/skills/gstack|g" \
           -e "s|~/.claude/skills/gstack|~/.kiro/skills/gstack|g" \
-          -e "s|\.agents/skills/gstack|.kiro/skills/gstack|g" \
-          -e "s|\.agents/skills|.kiro/skills|g" \
           "$skill_dir/SKILL.md" > "$target_dir/SKILL.md"
     done
     echo "gstack ready (kiro)."
diff --git a/ship/SKILL.md b/ship/SKILL.md
index 23b3ed1e..f5af3735 100644
--- a/ship/SKILL.md
+++ b/ship/SKILL.md
@@ -1112,7 +1112,7 @@ TMPERR_ADV=$(mktemp /tmp/codex-adv-XXXXXXXX)
 codex exec "Review the changes on this branch against the base branch. Run git diff origin/<base> to see the diff. Your job is to find ways this code will fail in production. Think like an attacker and a chaos engineer. Find edge cases, race conditions, security holes, resource leaks, failure modes, and silent data corruption paths. Be adversarial. Be thorough. No compliments — just the problems." -s read-only -c 'model_reasoning_effort="xhigh"' --enable web_search_cached 2>"$TMPERR_ADV"
 ```
 
-Use a 5-minute timeout (`timeout: 300000`). After the command completes, read stderr:
+Set the Bash tool's `timeout` parameter to `300000` (5 minutes). Do NOT use the `timeout` shell command — it doesn't exist on macOS. After the command completes, read stderr:
 ```bash
 cat "$TMPERR_ADV"
 ```
@@ -1157,7 +1157,7 @@ TMPERR=$(mktemp /tmp/codex-review-XXXXXXXX)
 codex review --base <base> -c 'model_reasoning_effort="xhigh"' --enable web_search_cached 2>"$TMPERR"
 ```
 
-Use a 5-minute timeout. Present output under `CODEX SAYS (code review):` header.
+Set the Bash tool's `timeout` parameter to `300000` (5 minutes). Do NOT use the `timeout` shell command — it doesn't exist on macOS. Present output under `CODEX SAYS (code review):` header.
 Check for `[P1]` markers: found → `GATE: FAIL`, not found → `GATE: PASS`.
 
 If GATE is FAIL, use AskUserQuestion:
diff --git a/test/gen-skill-docs.test.ts b/test/gen-skill-docs.test.ts
index ce32b343..95f615c2 100644
--- a/test/gen-skill-docs.test.ts
+++ b/test/gen-skill-docs.test.ts
@@ -967,7 +967,10 @@ describe('Codex generation (--host codex)', () => {
     for (const skill of ALL_SKILLS) {
       const content = fs.readFileSync(path.join(ROOT, skill.dir, 'SKILL.md'), 'utf-8');
       expect(content).not.toContain('~/.codex/');
-      expect(content).not.toContain('.agents/skills');
+      // gstack-upgrade legitimately references .agents/skills for cross-platform detection
+      if (skill.dir !== 'gstack-upgrade') {
+        expect(content).not.toContain('.agents/skills');
+      }
     }
   });
 });