diff --git a/lib/clean/dev.sh b/lib/clean/dev.sh
index aa6ec52..4728a3e 100644
--- a/lib/clean/dev.sh
+++ b/lib/clean/dev.sh
@@ -173,8 +173,56 @@ check_android_ndk() {
         "Android Studio → SDK Manager"
 }
 
+clean_xcode_documentation_cache() {
+    local doc_cache_root="${MOLE_XCODE_DOCUMENTATION_CACHE_DIR:-/Library/Developer/Xcode/DocumentationCache}"
+    [[ -d "$doc_cache_root" ]] || return 0
+
+    if pgrep -x "Xcode" > /dev/null 2>&1; then
+        echo -e "  ${GRAY}${ICON_WARNING}${NC} Xcode is running, skipping documentation cache cleanup"
+        note_activity
+        return 0
+    fi
+
+    local -a index_entries=()
+    while IFS= read -r -d '' entry; do
+        index_entries+=("$entry")
+    done < <(command find "$doc_cache_root" -mindepth 1 -maxdepth 1 \( -name "DeveloperDocumentation.index" -o -name "DeveloperDocumentation*.index" \) -print0 2> /dev/null)
+
+    if [[ ${#index_entries[@]} -le 1 ]]; then
+        return 0
+    fi
+
+    local -a sorted_entries=()
+    while IFS= read -r line; do
+        sorted_entries+=("${line#* }")
+    done < <(
+        for entry in "${index_entries[@]}"; do
+            mtime=$(stat -f%m "$entry" 2> /dev/null || echo "0")
+            printf '%s %s\n' "$mtime" "$entry"
+        done | sort -rn
+    )
+
+    local -a stale_entries=()
+    local idx=0
+    local entry
+    for entry in "${sorted_entries[@]}"; do
+        if [[ $idx -eq 0 ]]; then
+            ((idx++))
+            continue
+        fi
+        stale_entries+=("$entry")
+        ((idx++))
+    done
+
+    if [[ ${#stale_entries[@]} -gt 0 ]]; then
+        safe_clean "${stale_entries[@]}" "Xcode documentation cache (old indexes)"
+        note_activity
+    fi
+}
+
 clean_dev_mobile() {
     check_android_ndk
+    clean_xcode_documentation_cache
 
     if command -v xcrun > /dev/null 2>&1; then
         debug_log "Checking for unavailable Xcode simulators"
diff --git a/tests/clean_dev_caches.bats b/tests/clean_dev_caches.bats
index 97aca2e..da4e5b3 100644
--- a/tests/clean_dev_caches.bats
+++ b/tests/clean_dev_caches.bats
@@ -90,6 +90,7 @@ clean_dev_cloud() { :; }
 clean_dev_nix() { :; }
 clean_dev_shell() { :; }
 clean_dev_frontend() { :; }
+clean_xcode_documentation_cache() { :; }
 clean_dev_mobile() { :; }
 clean_dev_jvm() { :; }
 clean_dev_other_langs() { :; }
diff --git a/tests/dev_extended.bats b/tests/dev_extended.bats
index d6c19fd..0ecee83 100644
--- a/tests/dev_extended.bats
+++ b/tests/dev_extended.bats
@@ -136,6 +136,53 @@ EOF
     [[ "$output" != *"NDK versions"* ]]
 }
 
+@test "clean_xcode_documentation_cache keeps newest DeveloperDocumentation index" {
+    local doc_root="$HOME/DocumentationCache"
+    mkdir -p "$doc_root"
+    touch "$doc_root/DeveloperDocumentation.index"
+    touch "$doc_root/DeveloperDocumentation-16.0.index"
+    touch -t 202402010000 "$doc_root/DeveloperDocumentation.index"
+    touch -t 202401010000 "$doc_root/DeveloperDocumentation-16.0.index"
+
+    run env HOME="$HOME" PROJECT_ROOT="$PROJECT_ROOT" MOLE_XCODE_DOCUMENTATION_CACHE_DIR="$doc_root" bash --noprofile --norc <<'EOF'
+set -euo pipefail
+source "$PROJECT_ROOT/lib/core/common.sh"
+source "$PROJECT_ROOT/lib/clean/dev.sh"
+note_activity() { :; }
+safe_clean() {
+    local description="${*: -1}"
+    local target="$1"
+    echo "CLEAN:$target:$description"
+}
+clean_xcode_documentation_cache
+EOF
+
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"CLEAN:$doc_root/DeveloperDocumentation-16.0.index:Xcode documentation cache (old indexes)"* ]]
+    [[ "$output" != *"CLEAN:$doc_root/DeveloperDocumentation.index:Xcode documentation cache (old indexes)"* ]]
+}
+
+@test "clean_xcode_documentation_cache skips when Xcode is running" {
+    local doc_root="$HOME/DocumentationCache"
+    mkdir -p "$doc_root"
+    touch "$doc_root/DeveloperDocumentation.index"
+    touch "$doc_root/DeveloperDocumentation-16.0.index"
+
+    run env HOME="$HOME" PROJECT_ROOT="$PROJECT_ROOT" MOLE_XCODE_DOCUMENTATION_CACHE_DIR="$doc_root" bash --noprofile --norc <<'EOF'
+set -euo pipefail
+source "$PROJECT_ROOT/lib/core/common.sh"
+source "$PROJECT_ROOT/lib/clean/dev.sh"
+note_activity() { :; }
+pgrep() { return 0; }
+safe_clean() { echo "UNEXPECTED_SAFE_CLEAN"; }
+clean_xcode_documentation_cache
+EOF
+
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"skipping documentation cache cleanup"* ]]
+    [[ "$output" != *"UNEXPECTED_SAFE_CLEAN"* ]]
+}
+
 @test "check_rust_toolchains reports multiple toolchains" {
     run bash -c 'HOME=$(mktemp -d) && mkdir -p "$HOME/.rustup/toolchains"/{stable,nightly,1.75.0}-aarch64-apple-darwin && source "$0" && note_activity() { :; } && NC="" && GREEN="" && GRAY="" && YELLOW="" && ICON_SUCCESS="✓" && rustup() { :; } && export -f rustup && check_rust_toolchains' "$PROJECT_ROOT/lib/clean/dev.sh"