fix: propagate codex exit code, safe arithmetic, preserve cwd

- Add script -e flag so codex exit code propagates through PTY wrapper
- Use subshell for git repo check to avoid changing caller's cwd
  (fixes broken relative --workdir paths)
- Replace ((ERRORS++)) with ERRORS=$((ERRORS + 1)) to avoid set -e
  terminating on first verification failure
- Add script binary to installer dependency check

skills/claude-codex-delegation/install.sh

@@ -114,11 +114,21 @@ if ! command -v timeout &> /dev/null; then
     if [[ "$(uname)" == "Darwin" ]]; then
         echo "  Install with: brew install coreutils"
     fi
-    ((MISSING++))
+    MISSING=$((MISSING + 1))
 else
     info "timeout: available"
 fi
 
+if ! command -v script &> /dev/null; then
+    error "'script' (from util-linux) is required for Codex PTY support."
+    if [[ "$(uname)" == "Darwin" ]]; then
+        echo "  Install with: brew install util-linux"
+    fi
+    MISSING=$((MISSING + 1))
+else
+    info "script: available"
+fi
+
 if command -v tmux &> /dev/null; then
     info "tmux: available"
 else
@@ -126,7 +136,7 @@ else
 fi
 
 if [[ $MISSING -gt 0 ]]; then
-    error "Missing $MISSING required system dependency. Install it and rerun."
+    error "Missing $MISSING required system dependencies. Install them and rerun."
     exit 1
 fi
 
@@ -198,35 +208,35 @@ if command -v claude &> /dev/null || $DRY_RUN; then
     info "claude CLI: OK"
 else
     error "claude CLI: not found"
-    ((ERRORS++))
+    ERRORS=$((ERRORS + 1))
 fi
 
 if command -v codex &> /dev/null || $DRY_RUN; then
     info "codex CLI: OK"
 else
     error "codex CLI: not found"
-    ((ERRORS++))
+    ERRORS=$((ERRORS + 1))
 fi
 
 if [[ -f "$SKILL_DIR/SKILL.md" ]] || $DRY_RUN; then
     info "SKILL.md: OK"
 else
     error "SKILL.md: not found at $SKILL_DIR"
-    ((ERRORS++))
+    ERRORS=$((ERRORS + 1))
 fi
 
 if [[ -x "$SKILL_DIR/scripts/delegate.sh" ]] || $DRY_RUN; then
     info "scripts/delegate.sh: OK"
 else
     error "scripts/delegate.sh: not found or not executable"
-    ((ERRORS++))
+    ERRORS=$((ERRORS + 1))
 fi
 
 if [[ -x "$SKILL_DIR/scripts/tmux-session.sh" ]] || $DRY_RUN; then
     info "scripts/tmux-session.sh: OK"
 else
     error "scripts/tmux-session.sh: not found or not executable"
-    ((ERRORS++))
+    ERRORS=$((ERRORS + 1))
 fi
 
 # --- Auth check ---

skills/claude-codex-delegation/scripts/delegate.sh

@@ -118,8 +118,7 @@ fi
 
 # Codex requires a git repository — fail fast instead of silently mutating
 if [[ "$AGENT" == "codex" ]]; then
-    cd "$WORKDIR"
-    if [[ ! -d .git ]] && ! git rev-parse --git-dir > /dev/null 2>&1; then
+    if ! (cd "$WORKDIR" && { [[ -d .git ]] || git rev-parse --git-dir > /dev/null 2>&1; }); then
         echo "Error: Codex requires a git repository but $WORKDIR is not one." >&2
         echo "Initialize one with: cd $WORKDIR && git init" >&2
         exit 1
@@ -167,9 +166,10 @@ run_delegation() {
             ;;
         codex)
             # Codex requires a PTY — use script(1) to provide one.
+            # -e: propagate child exit code (without it, script always returns 0)
             # Run through bash -c so printf '%q' quoting is interpreted correctly
             # (script passes commands to /bin/sh which may be dash, not bash).
-            script -q -c "bash -c $(printf '%q' "$(build_codex_cmd) $(printf '%q' "$PROMPT")")" "$LOG_FILE" || exit_code=$?
+            script -e -q -c "bash -c $(printf '%q' "$(build_codex_cmd) $(printf '%q' "$PROMPT")")" "$LOG_FILE" || exit_code=$?
             ;;
     esac
 

skills/claude-codex-delegation/scripts/tmux-session.sh

@@ -128,8 +128,7 @@ case "$ACTION" in
 
         # Codex requires a git repo
         if [[ "$AGENT" == "codex" ]]; then
-            cd "$WORKDIR"
-            if [[ ! -d .git ]] && ! git rev-parse --git-dir > /dev/null 2>&1; then
+            if ! (cd "$WORKDIR" && { [[ -d .git ]] || git rev-parse --git-dir > /dev/null 2>&1; }); then
                 echo "Error: Codex requires a git repository but $WORKDIR is not one." >&2
                 echo "Initialize one with: cd $WORKDIR && git init" >&2
                 exit 1