diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 691c6d37..9d8f65cf 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,6 +10,9 @@ on:
       - "**/Cargo.lock"
       - "rust-toolchain.toml"
       - "scripts/install.sh"
+      - "scripts/install-cli.sh"
+      - "scripts/install-completions.sh"
+      - "scripts/tests/verify-completion-install.sh"
       - "scripts/run-with-capabilities.sh"
       - "scripts/tests/setup-ublk-access.sh"
       - "scripts/tests/verify-capability-runner.sh"
@@ -24,6 +27,9 @@ on:
       - "**/Cargo.lock"
       - "rust-toolchain.toml"
       - "scripts/install.sh"
+      - "scripts/install-cli.sh"
+      - "scripts/install-completions.sh"
+      - "scripts/tests/verify-completion-install.sh"
       - "scripts/run-with-capabilities.sh"
       - "scripts/tests/setup-ublk-access.sh"
       - "scripts/tests/verify-capability-runner.sh"
@@ -63,3 +69,16 @@ jobs:
         run: sudo scripts/tests/setup-ublk-access.sh "$(id -un)" "$(id -gn)"
       - name: Unit tests
         run: make test-unit PROFILE=debug
+
+  completion-install:
+    name: Completion installer checks
+    runs-on: ubuntu-22.04
+    timeout-minutes: 5
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@v6
+      - name: Shell syntax
+        run: bash -n scripts/install-completions.sh scripts/install-cli.sh scripts/install.sh scripts/tests/verify-completion-install.sh
+      - name: Functional checks
+        run: bash scripts/tests/verify-completion-install.sh
diff --git a/Makefile b/Makefile
index 116b30c0..16055570 100644
--- a/Makefile
+++ b/Makefile
@@ -50,6 +50,7 @@ TARGET_PROFILE_DIR = $${CARGO_TARGET_DIR:-$$(pwd)/target}/$(PROFILE)
 	build-server build-server-release \
 	build-snapshot-image \
 	build-aenv build-aenv-release install-aenv uninstall-aenv \
+	check-completion-install \
 	build-ublk install-ublk \
 	fmt clippy \
 	mutants coverage \
@@ -91,12 +92,17 @@ build-aenv-release:
 install-aenv: build-aenv-release
 	$(AENV_INSTALL_SUDO) install -d "$(AENV_INSTALL_DIR)"
 	$(AENV_INSTALL_SUDO) install -m 0755 "$${CARGO_TARGET_DIR:-$$(pwd)/target}/release/aenv" "$(AENV_INSTALL_DIR)/aenv"
+	$(AENV_INSTALL_SUDO) scripts/install-completions.sh install --prefix="$(AENV_INSTALL_PREFIX)" --binary="$(AENV_INSTALL_DIR)/aenv"
 	@echo "Installed aenv to $(AENV_INSTALL_DIR)/aenv"
 
 uninstall-aenv:
+	$(AENV_INSTALL_SUDO) scripts/install-completions.sh uninstall --prefix="$(AENV_INSTALL_PREFIX)" --binary="$(AENV_INSTALL_DIR)/aenv"
 	$(AENV_INSTALL_SUDO) rm -f "$(AENV_INSTALL_DIR)/aenv"
 	@echo "Removed $(AENV_INSTALL_DIR)/aenv"
 
+check-completion-install:
+	bash scripts/tests/verify-completion-install.sh
+
 fmt:
 	$(CARGO) fmt --all -- --check
 
@@ -119,6 +125,7 @@ test-unit:
 	$(CAPABILITY_TEST_ENV) $(CAPABILITY_RUNNER) $(CARGO) test -p uvm-ublk -p uvm-ublk-daemon --lib
 	bash scripts/tests/verify-capability-runner.sh
 	bash scripts/tests/verify-install-service.sh
+	bash scripts/tests/verify-completion-install.sh
 
 test-integration: test-agent-integration test-envd test-ublk
 
diff --git a/docs/src/getting-started/aenv-cli.md b/docs/src/getting-started/aenv-cli.md
index 53104f5b..8e3d9283 100644
--- a/docs/src/getting-started/aenv-cli.md
+++ b/docs/src/getting-started/aenv-cli.md
@@ -274,3 +274,15 @@ aenv snapshot list --sandbox-id <sandbox-id>
 The table output includes an `IMAGE REF` column (`-` when no image was published); JSON output includes the optional `imageRef` field.
 
 To delete a snapshot, use `aenv template delete <snapshot-id>` or `aenv template delete <name>` — snapshots share the same underlying store as templates and are deleted through the same command.
+
+## Automatic shell completion installation
+
+The CLI installers install completion loaders into standard shell completion directories. `make install-aenv`, `scripts/install-cli.sh`, and the full `scripts/install.sh` installer manage only the completion files and never modify `.bashrc`, `.zshrc`, or Fish configuration files. `make uninstall-aenv` removes files created by the Make-based install while preserving unmanaged files.
+
+For a user-local Make install, use `AENV_INSTALL_PREFIX=~/.local AENV_INSTALL_SUDO= make install-aenv`. If Zsh does not find the installed user completion directory, add this before `compinit`:
+
+```zsh
+fpath=(~/.local/share/zsh/site-functions $fpath)
+autoload -Uz compinit
+compinit
+```
diff --git a/scripts/install-cli.sh b/scripts/install-cli.sh
index 18cbb437..8e9b4934 100644
--- a/scripts/install-cli.sh
+++ b/scripts/install-cli.sh
@@ -165,6 +165,103 @@ fi
 
 echo "Installed: ${DEST}"
 
+install_completion_files() {
+    local marker='# managed by aenv completion installer'
+    local prefix home user_mode=0 quoted_binary
+    local bash_path zsh_path fish_path
+    prefix="$(dirname "$INSTALL_DIR")"
+    home="${HOME:-}"
+    canonical_dir() {
+        local path="$1" parent name
+        [[ "$path" == /* ]] || path="$PWD/$path"
+        if [[ -d "$path" ]]; then
+            (cd "$path" && pwd -P)
+            return
+        fi
+        parent="${path%/*}"
+        name="${path##*/}"
+        [[ "$parent" == "$path" ]] && parent="."
+        parent="$(cd "$parent" 2>/dev/null && pwd -P)" || return 1
+        printf '%s/%s\n' "$parent" "$name"
+    }
+    prefix="$(canonical_dir "$prefix")" || { echo "warning: could not resolve completion prefix; skipping" >&2; return 0; }
+    home_real=""
+    if [[ -n "$home" ]]; then
+        home_real="$(canonical_dir "$home")" || home_real=""
+    fi
+    if [[ -n "$home_real" && ( "$prefix" == "$home_real" || "$prefix" == "$home_real"/* ) ]]; then
+        user_mode=1
+    fi
+    if ((user_mode)); then
+        [[ -n "$home" ]] || { echo "warning: HOME is unset; skipping completion setup" >&2; return 0; }
+        bash_path="$home/.local/share/bash-completion/completions/aenv"
+        zsh_path="$home/.local/share/zsh/site-functions/_aenv"
+        fish_path="$home/.config/fish/completions/aenv.fish"
+    else
+        bash_path="$prefix/share/bash-completion/completions/aenv"
+        zsh_path="$prefix/share/zsh/site-functions/_aenv"
+        fish_path="$prefix/share/fish/vendor_completions.d/aenv.fish"
+    fi
+    if [[ "$DEST" == *"'"* || "$DEST" == *$'\n'* || "$DEST" == *$'\r'* ]]; then
+        echo "warning: completion binary path contains unsupported characters; skipping" >&2
+        return 0
+    fi
+    quoted_binary="'$DEST'"
+
+    put_loader() {
+        local path="$1" body="$2" dir tmp
+        dir="${path%/*}"
+        if [[ -L "$path" ]]; then
+            echo "warning: refusing to replace symlink ${path}" >&2
+            return 0
+        fi
+        if [[ -e "$path" ]] && ! grep -Fqx "$marker" "$path" 2>/dev/null; then
+            echo "warning: leaving unmanaged completion file ${path} untouched" >&2
+            return 0
+        fi
+        local runner=()
+        if ! (mkdir -p "$dir" 2>/dev/null && [[ -w "$dir" ]]); then
+            runner=(run_privileged)
+        fi
+        "${runner[@]}" mkdir -p "$dir" || { echo "warning: could not create ${dir}" >&2; return 0; }
+        tmp="$("${runner[@]}" mktemp "$dir/.aenv-completion.XXXXXX")" || {
+            echo "warning: could not stage ${path}" >&2
+            return 0
+        }
+        if [[ "$path" == "$zsh_path" ]]; then
+            if ! printf '%s\n%s\n' "$body" "$marker" | "${runner[@]}" tee "$tmp" >/dev/null; then
+                "${runner[@]}" rm -f "$tmp"
+                echo "warning: could not stage ${path}" >&2
+                return 0
+            fi
+        else
+            if ! printf '%s\n%s\n' "$marker" "$body" | "${runner[@]}" tee "$tmp" >/dev/null; then
+                "${runner[@]}" rm -f "$tmp"
+                echo "warning: could not stage ${path}" >&2
+                return 0
+            fi
+        fi
+        if ! "${runner[@]}" chmod 0644 "$tmp" || ! "${runner[@]}" mv -f "$tmp" "$path"; then
+            "${runner[@]}" rm -f "$tmp"
+            echo "warning: could not install ${path}" >&2
+        fi
+    }
+
+    put_loader "$bash_path" "if [[ -x $quoted_binary ]]; then source <($quoted_binary completion bash); fi"
+    zsh_body="#compdef aenv
+if [[ -x $quoted_binary ]]; then eval \"\$($quoted_binary completion zsh)\"; fi"
+    put_loader "$zsh_path" "$zsh_body"
+    put_loader "$fish_path" "if test -x $quoted_binary; $quoted_binary completion fish | source; end"
+    if ((user_mode)); then
+        echo "If Zsh does not find the completion, add this before compinit:"
+        echo "  fpath=(~/.local/share/zsh/site-functions \$fpath)"
+        echo "  autoload -Uz compinit"
+        echo "  compinit"
+    fi
+}
+
+install_completion_files
+
 if ! command -v aenv &>/dev/null; then
     echo ""
     echo "Note: ${INSTALL_DIR} is not on your PATH."
diff --git a/scripts/install-completions.sh b/scripts/install-completions.sh
new file mode 100755
index 00000000..e29c1cf0
--- /dev/null
+++ b/scripts/install-completions.sh
@@ -0,0 +1,137 @@
+#!/usr/bin/env bash
+# Install or remove aenv completion loaders without editing shell startup files.
+set -euo pipefail
+
+MARKER='# managed by aenv completion installer'
+
+usage() {
+    printf 'Usage: %s <install|uninstall> --prefix=<prefix> --binary=<aenv>\n' "$0" >&2
+}
+
+action="${1:-}"
+shift || true
+prefix=""
+binary=""
+while (($#)); do
+    case "$1" in
+        --prefix=*) prefix="${1#--prefix=}" ;;
+        --binary=*) binary="${1#--binary=}" ;;
+        *) usage; exit 2 ;;
+    esac
+    shift
+done
+
+if [[ "$action" != install && "$action" != uninstall ]] || [[ -z "$prefix" || -z "$binary" ]]; then
+    usage
+    exit 2
+fi
+
+home="${HOME:-}"
+user_mode=0
+canonical_dir() {
+    local path="$1" parent name
+    [[ "$path" == /* ]] || path="$PWD/$path"
+    if [[ -d "$path" ]]; then
+        (cd "$path" && pwd -P)
+        return
+    fi
+    parent="${path%/*}"
+    name="${path##*/}"
+    [[ "$parent" == "$path" ]] && parent="."
+    parent="$(cd "$parent" 2>/dev/null && pwd -P)" || return 1
+    printf '%s/%s\n' "$parent" "$name"
+}
+
+prefix_real="$(canonical_dir "$prefix")" || {
+    printf 'warning: could not resolve completion prefix %s; skipping\n' "$prefix" >&2
+    exit 0
+}
+home_real=""
+if [[ -n "$home" ]]; then
+    home_real="$(canonical_dir "$home")" || home_real=""
+fi
+if [[ -n "$home_real" && ( "$prefix_real" == "$home_real" || "$prefix_real" == "$home_real"/* ) ]]; then
+    user_mode=1
+fi
+
+if ((user_mode)); then
+    [[ -n "$home" ]] || { printf 'warning: HOME is unset; skipping completion setup\n' >&2; exit 0; }
+    bash_path="$home/.local/share/bash-completion/completions/aenv"
+    zsh_path="$home/.local/share/zsh/site-functions/_aenv"
+    fish_path="$home/.config/fish/completions/aenv.fish"
+else
+    bash_path="$prefix/share/bash-completion/completions/aenv"
+    zsh_path="$prefix/share/zsh/site-functions/_aenv"
+    fish_path="$prefix/share/fish/vendor_completions.d/aenv.fish"
+fi
+
+if [[ "$binary" == *"'"* || "$binary" == *$'\n'* || "$binary" == *$'\r'* ]]; then
+    printf 'warning: completion binary path contains unsupported characters; skipping\n' >&2
+    exit 0
+fi
+quoted_binary="'$binary'"
+
+write_loader() {
+    local path="$1" body="$2" dir tmp
+    dir="${path%/*}"
+    mkdir -p "$dir" 2>/dev/null || {
+        printf 'warning: could not create completion directory %s\n' "$dir" >&2
+        return 0
+    }
+    if [[ -L "$path" ]]; then
+        printf 'warning: refusing to replace symlink %s\n' "$path" >&2
+        return 0
+    fi
+    if [[ -e "$path" ]] && ! grep -Fqx "$MARKER" "$path" 2>/dev/null; then
+        printf 'warning: leaving unmanaged completion file %s untouched\n' "$path" >&2
+        return 0
+    fi
+    tmp="$(mktemp "$dir/.aenv-completion.XXXXXX")" || {
+        printf 'warning: could not stage completion file %s\n' "$path" >&2
+        return 0
+    }
+    if [[ "$path" == "$zsh_path" ]]; then
+        if ! printf '%s\n%s\n' "$body" "$MARKER" >"$tmp"; then
+            rm -f "$tmp"
+            printf 'warning: could not stage completion file %s\n' "$path" >&2
+            return 0
+        fi
+    else
+        if ! printf '%s\n%s\n' "$MARKER" "$body" >"$tmp"; then
+            rm -f "$tmp"
+            printf 'warning: could not stage completion file %s\n' "$path" >&2
+            return 0
+        fi
+    fi
+    if ! { chmod 0644 "$tmp" && mv -f "$tmp" "$path"; }; then
+        rm -f "$tmp"
+        printf 'warning: could not install completion file %s\n' "$path" >&2
+    fi
+}
+
+remove_loader() {
+    local path="$1"
+    [[ -e "$path" ]] || return 0
+    if [[ -L "$path" ]] || ! grep -Fqx "$MARKER" "$path" 2>/dev/null; then
+        printf 'warning: leaving unmanaged completion file %s untouched\n' "$path" >&2
+        return 0
+    fi
+    rm -f "$path" || printf 'warning: could not remove completion file %s\n' "$path" >&2
+}
+
+if [[ "$action" == install ]]; then
+    write_loader "$bash_path" "if [[ -x $quoted_binary ]]; then source <($quoted_binary completion bash); fi"
+    zsh_body="#compdef aenv
+if [[ -x $quoted_binary ]]; then eval \"\$($quoted_binary completion zsh)\"; fi"
+    write_loader "$zsh_path" "$zsh_body"
+    write_loader "$fish_path" "if test -x $quoted_binary; $quoted_binary completion fish | source; end"
+    if ((user_mode)); then
+        printf '\nIf Zsh does not find the completion, add this before compinit:\n'
+        printf "  fpath=(~/.local/share/zsh/site-functions \$fpath)\n"
+        printf '  autoload -Uz compinit\n  compinit\n'
+    fi
+else
+    remove_loader "$bash_path"
+    remove_loader "$zsh_path"
+    remove_loader "$fish_path"
+fi
diff --git a/scripts/install.sh b/scripts/install.sh
index a2dbce88..389ef541 100644
--- a/scripts/install.sh
+++ b/scripts/install.sh
@@ -170,6 +170,58 @@ echo "Downloading aenv CLI ..."
 download_release_asset "aenv-linux-${ARCH_TAG}" "$tmp_cli"
 sudo install -m 0755 "$tmp_cli" "${INSTALL_DIR}/aenv"
 
+install_completion_files() {
+    local marker='# managed by aenv completion installer'
+    local binary="${INSTALL_DIR}/aenv" quoted_binary
+    local bash_path="/usr/local/share/bash-completion/completions/aenv"
+    local zsh_path="/usr/local/share/zsh/site-functions/_aenv"
+    local fish_path="/usr/local/share/fish/vendor_completions.d/aenv.fish"
+    quoted_binary="'$binary'"
+
+    put_loader() {
+        local path="$1" body="$2" dir tmp
+        dir="${path%/*}"
+        if [[ -L "$path" ]]; then
+            echo "warning: refusing to replace symlink ${path}" >&2
+            return 0
+        fi
+        if [[ -e "$path" ]] && ! grep -Fqx "$marker" "$path" 2>/dev/null; then
+            echo "warning: leaving unmanaged completion file ${path} untouched" >&2
+            return 0
+        fi
+        sudo mkdir -p "$dir" || { echo "warning: could not create ${dir}" >&2; return 0; }
+        tmp="$(sudo mktemp "$dir/.aenv-completion.XXXXXX")" || {
+            echo "warning: could not stage ${path}" >&2
+            return 0
+        }
+        if [[ "$path" == "$zsh_path" ]]; then
+            if ! printf '%s\n%s\n' "$body" "$marker" | sudo tee "$tmp" >/dev/null; then
+                sudo rm -f "$tmp"
+                echo "warning: could not stage ${path}" >&2
+                return 0
+            fi
+        else
+            if ! printf '%s\n%s\n' "$marker" "$body" | sudo tee "$tmp" >/dev/null; then
+                sudo rm -f "$tmp"
+                echo "warning: could not stage ${path}" >&2
+                return 0
+            fi
+        fi
+        if ! sudo chmod 0644 "$tmp" || ! sudo mv -f "$tmp" "$path"; then
+            sudo rm -f "$tmp"
+            echo "warning: could not install ${path}" >&2
+        fi
+    }
+
+    put_loader "$bash_path" "if [[ -x $quoted_binary ]]; then source <($quoted_binary completion bash); fi"
+    zsh_body="#compdef aenv
+if [[ -x $quoted_binary ]]; then eval \"\$($quoted_binary completion zsh)\"; fi"
+    put_loader "$zsh_path" "$zsh_body"
+    put_loader "$fish_path" "if test -x $quoted_binary; $quoted_binary completion fish | source; end"
+}
+
+install_completion_files
+
 # ---------------------------------------------------------------------------
 # 2. Install the server
 # ---------------------------------------------------------------------------
diff --git a/scripts/tests/verify-completion-install.sh b/scripts/tests/verify-completion-install.sh
new file mode 100755
index 00000000..6a36b62c
--- /dev/null
+++ b/scripts/tests/verify-completion-install.sh
@@ -0,0 +1,120 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+helper="$repo_root/scripts/install-completions.sh"
+tmp_root="$(mktemp -d)"
+trap 'rm -rf "$tmp_root"' EXIT
+
+home="$tmp_root/home"
+bin="$tmp_root/bin"
+prefix="$tmp_root/prefix"
+mkdir -p "$home" "$bin" "$prefix"
+
+printf '#!/usr/bin/env bash\necho completion\n' > "$bin/aenv-v1"
+printf '#!/usr/bin/env bash\necho newer-completion\n' > "$bin/aenv-v2"
+chmod 0755 "$bin/aenv-v1" "$bin/aenv-v2"
+
+bash_file="$home/.local/share/bash-completion/completions/aenv"
+zsh_file="$home/.local/share/zsh/site-functions/_aenv"
+fish_file="$home/.config/fish/completions/aenv.fish"
+marker='# managed by aenv completion installer'
+
+fail() { printf 'FAIL: %s\n' "$*" >&2; exit 1; }
+assert_file() { [[ -f "$1" ]] || fail "expected file $1"; }
+assert_absent() { [[ ! -e "$1" ]] || fail "expected $1 to be absent"; }
+assert_contains() { grep -Fq -- "$2" "$1" || fail "expected $1 to contain: $2"; }
+file_mode() {
+    stat -c '%a' "$1" 2>/dev/null || stat -f '%Lp' "$1"
+}
+
+echo '==> user install creates standard loaders'
+HOME="$home" bash "$helper" install --prefix="$home/.local" --binary="$bin/aenv-v1" >/dev/null
+assert_file "$bash_file"
+assert_file "$zsh_file"
+assert_file "$fish_file"
+assert_contains "$bash_file" "$marker"
+assert_contains "$zsh_file" '#compdef aenv'
+[[ "$(sed -n '1p' "$zsh_file")" == '#compdef aenv' ]] || fail 'zsh #compdef must remain first'
+[[ "$(file_mode "$bash_file")" == 644 ]] || fail 'Bash loader mode must be 0644'
+[[ "$(file_mode "$zsh_file")" == 644 ]] || fail 'Zsh loader mode must be 0644'
+[[ "$(file_mode "$fish_file")" == 644 ]] || fail 'Fish loader mode must be 0644'
+[[ ! -e "$home/.zshrc" ]] || fail 'installer must not create .zshrc'
+
+if command -v zsh >/dev/null 2>&1; then
+    zsh -n "$zsh_file"
+fi
+if command -v fish >/dev/null 2>&1; then
+    fish -n "$fish_file"
+fi
+bash -n "$bash_file"
+
+echo '==> unmanaged files are preserved'
+printf '# user completion\n' > "$bash_file"
+printf '# user zsh completion\n' > "$zsh_file"
+printf '# user fish completion\n' > "$fish_file"
+HOME="$home" bash "$helper" install --prefix="$home/.local" --binary="$bin/aenv-v2" >/dev/null
+assert_contains "$bash_file" '# user completion'
+assert_contains "$zsh_file" '# user zsh completion'
+assert_contains "$fish_file" '# user fish completion'
+
+echo '==> uninstall preserves unmanaged files'
+HOME="$home" bash "$helper" uninstall --prefix="$home/.local" --binary="$bin/aenv-v2" >/dev/null
+assert_contains "$bash_file" '# user completion'
+assert_contains "$zsh_file" '# user zsh completion'
+assert_contains "$fish_file" '# user fish completion'
+
+echo '==> managed files are upgraded'
+rm -f "$bash_file" "$zsh_file" "$fish_file"
+HOME="$home" bash "$helper" install --prefix="$home/.local" --binary="$bin/aenv-v1" >/dev/null
+HOME="$home" bash "$helper" install --prefix="$home/.local" --binary="$bin/aenv-v2" >/dev/null
+assert_contains "$bash_file" "$bin/aenv-v2"
+[[ "$(file_mode "$bash_file")" == 644 ]] || fail 'upgraded loader mode must be 0644'
+
+echo '==> uninstall removes only managed files'
+HOME="$home" bash "$helper" uninstall --prefix="$home/.local" --binary="$bin/aenv-v2" >/dev/null
+assert_absent "$bash_file"
+assert_absent "$zsh_file"
+assert_absent "$fish_file"
+
+echo '==> symlink destinations are preserved'
+symlink_target="$tmp_root/user-completion"
+printf '# user target\n' > "$symlink_target"
+ln -s "$symlink_target" "$bash_file"
+HOME="$home" bash "$helper" install --prefix="$home/.local" --binary="$bin/aenv-v1" >/dev/null
+[[ -L "$bash_file" ]] || fail 'completion symlink was replaced'
+assert_contains "$symlink_target" '# user target'
+rm -f "$bash_file"
+
+echo '==> staging failures leave no temporary files'
+fake_tools="$tmp_root/fake-tools"
+mkdir -p "$fake_tools"
+printf '#!/usr/bin/env bash\nexit 1\n' > "$fake_tools/mktemp"
+chmod 0755 "$fake_tools/mktemp"
+HOME="$home" PATH="$fake_tools:$PATH" bash "$helper" install --prefix="$home/.local" --binary="$bin/aenv-v1" >/dev/null
+shopt -s nullglob
+leftovers=(
+    "$home/.local/share/bash-completion/completions"/.aenv-completion.*
+    "$home/.local/share/zsh/site-functions"/.aenv-completion.*
+    "$home/.config/fish/completions"/.aenv-completion.*
+)
+[[ "${#leftovers[@]}" -eq 0 ]] || fail 'staging failure left a temporary completion file'
+
+echo '==> system paths use the prefix share directories'
+HOME="$home" bash "$helper" install --prefix="$prefix" --binary="$bin/aenv-v1" >/dev/null
+assert_file "$prefix/share/bash-completion/completions/aenv"
+assert_file "$prefix/share/zsh/site-functions/_aenv"
+assert_file "$prefix/share/fish/vendor_completions.d/aenv.fish"
+HOME="$home" bash "$helper" uninstall --prefix="$prefix" --binary="$bin/aenv-v1" >/dev/null
+assert_absent "$prefix/share/bash-completion/completions/aenv"
+
+echo '==> path traversal cannot select user mode'
+outside="$tmp_root/outside"
+mkdir -p "$outside"
+HOME="$home" bash "$helper" install --prefix="$home/../outside" --binary="$bin/aenv-v1" >/dev/null
+assert_file "$outside/share/bash-completion/completions/aenv"
+assert_absent "$home/.local/share/bash-completion/completions/aenv"
+HOME="$home" bash "$helper" uninstall --prefix="$home/../outside" --binary="$bin/aenv-v1" >/dev/null
+assert_absent "$outside/share/bash-completion/completions/aenv"
+
+echo '==> completion installation checks passed'