diff --git a/README.md b/README.md
index 2500c1e..1d222af 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,10 @@ Git checkouts are updated with Git.
 `z.install` replaces the core while preserving installed mods.
 Use `z.install.mod <mod_name>` to update a single mod.
 
+`z.install.mod.list` lists available and installed mods: green for installed,
+orange for different contents, and red for not installed. It compares against
+`Z_INSTALL_BRANCH` (default: `main`); local edits also appear orange.
+
 ### Uninstall
 
 `z.uninstall`
diff --git a/lib/install/mod/list/analysis.zsh b/lib/install/mod/list/analysis.zsh
new file mode 100644
index 0000000..89aaf8e
--- /dev/null
+++ b/lib/install/mod/list/analysis.zsh
@@ -0,0 +1,32 @@
+# compare an installed mod with the selected distribution
+#
+# $source: distribution mod directory
+# $installed: installed mod directory
+# REPLY: installed|update-available|not-installed
+# return: 0 if compared, otherwise 1
+#
+# example:
+#  z.install.mod.list._status source=/tmp/source/git installed=~/.z/mod/git
+z.install.mod.list._status() {
+  z.arg.named source "$@" && local source_dir=$REPLY
+  z.arg.named installed "$@" && local installed_dir=$REPLY
+
+  if z.dir.not.exists "$installed_dir"; then
+    z.return not-installed
+    return
+  fi
+
+  if z.dir.not.exists "$source_dir"; then
+    z.return installed
+    return
+  fi
+
+  diff -qr -- "$source_dir" "$installed_dir" >/dev/null
+  local result_code=$?
+
+  case $result_code in
+  0) z.return installed ;;
+  1) z.return update-available ;;
+  *) return 1 ;;
+  esac
+}
diff --git a/lib/install/mod/list/process.zsh b/lib/install/mod/list/process.zsh
new file mode 100644
index 0000000..f2416be
--- /dev/null
+++ b/lib/install/mod/list/process.zsh
@@ -0,0 +1,27 @@
+# fetch the selected distribution's mod directory into a work directory
+#
+# $dir: existing work directory
+# $branch?: distribution branch (default: main)
+# REPLY: extracted mod directory
+# return: 0|1
+#
+# example:
+#  z.install.mod.list._fetch dir=/tmp/mod-list branch=main
+z.install.mod.list._fetch() {
+  z.arg.named dir "$@" && local dir=$REPLY
+  z.arg.named branch "$@" default=main && local branch=$REPLY
+
+  local archive="$dir/source.tar.gz"
+  local url="https://github.com/milkeclair/z/archive/refs/heads/$branch.tar.gz"
+
+  curl -fLsS "$url" -o "$archive" || return 1
+  tar -xzf "$archive" -C "$dir" || return 1
+
+  local roots=("$dir"/*(N/))
+  if ! z.int.is.eq ${#roots} 1 || z.dir.not.exists "$roots[1]/mod"; then
+    z.io.error "mod directory not found in the distribution"
+    return 1
+  fi
+
+  z.return "$roots[1]/mod"
+}
diff --git a/lib/install/mod/process.zsh b/lib/install/mod/process.zsh
new file mode 100644
index 0000000..01cf851
--- /dev/null
+++ b/lib/install/mod/process.zsh
@@ -0,0 +1,40 @@
+# list available and installed mods from the selected distribution branch
+# green: installed, orange: different contents, red: not installed
+# local edits are also shown as update-available
+#
+# REPLY: null
+# return: 0|1
+#
+# example:
+#  z.install.mod.list
+z.install.mod.list() {
+  local work_dir=$(mktemp -d)
+  z.dir.exists "$work_dir" || return 1
+
+  {
+    z.install.mod.list._fetch dir="$work_dir" branch="${Z_INSTALL_BRANCH:-main}" || return 1
+    local source_dir=$REPLY
+
+    local names=("$source_dir"/*(N/:t) "$z_root"/mod/*(N/:t))
+    z.arr.unique "${names[@]}"
+    z.arr.sort "${(@)REPLY}"
+    local mod_names=(${(@)REPLY})
+
+    for mod_name in "${mod_names[@]}"; do
+      z.install.mod.list._status source="$source_dir/$mod_name" installed="$z_root/mod/$mod_name" || return 1
+      local mod_state=$REPLY
+      local color=green
+
+      case $mod_state in
+      update-available) color=orange ;;
+      not-installed) color=red ;;
+      esac
+
+      z.io color="$color" "$mod_name [$mod_state]"
+    done
+  } always {
+    z.dir.remove path="$work_dir" || return 1
+  }
+
+  z.return
+}
diff --git a/lib/str/process.zsh b/lib/str/process.zsh
index 8725288..4153794 100644
--- a/lib/str/process.zsh
+++ b/lib/str/process.zsh
@@ -1,6 +1,7 @@
 typeset -gA z_color_palette=(
   [red]=$'\033[31m'
   [green]=$'\033[32m'
+  [orange]=$'\033[38;5;208m'
   [yellow]=$'\033[33m'
   [blue]=$'\033[34m'
   [magenta]=$'\033[35m'
diff --git a/main.zsh b/main.zsh
index eff82b7..3a1a4db 100644
--- a/main.zsh
+++ b/main.zsh
@@ -9,6 +9,7 @@ local -A z_modules=(
   [file]="operator:process"
   [fn]="analysis:operator:process"
   [hash]="analysis:operator:process"
+  [install]="process"
   [int]="operator"
   [io]="process"
   [mode]="process"
@@ -42,6 +43,7 @@ local z_module_depends_order=(
   str
   t
   update
+  install
 )
 
 local -A loaded_files=()
diff --git a/test/lib/install/mod/list/analysis_test.zsh b/test/lib/install/mod/list/analysis_test.zsh
new file mode 100644
index 0000000..71576b8
--- /dev/null
+++ b/test/lib/install/mod/list/analysis_test.zsh
@@ -0,0 +1,93 @@
+source "$z_main"
+
+z.t.describe "z.install.mod.list._status"; {
+  z.t.context "未インストールの場合"; {
+    z.t.it "not-installedを返す"; {
+      local fixture=$(mktemp -d /tmp/z_mod_status.XXXXXX)
+      z.dir.make path="$fixture/source"
+
+      z.install.mod.list._status source="$fixture/source" installed="$fixture/installed"
+
+      z.t.expect.reply not-installed
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "配布元と内容が一致する場合"; {
+    z.t.it "隠しfileとsubdirectoryも比較してinstalledを返す"; {
+      local fixture=$(mktemp -d /tmp/z_mod_status.XXXXXX)
+      z.dir.make path="$fixture/source/nested"
+      z.file.write path="$fixture/source/nested/value" content=same
+      z.file.write path="$fixture/source/.settings" content=same
+      cp -R "$fixture/source" "$fixture/installed"
+
+      z.install.mod.list._status source="$fixture/source" installed="$fixture/installed"
+
+      z.t.expect.reply installed
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "配布元とfileの内容が異なる場合"; {
+    z.t.it "update-availableを返す"; {
+      local fixture=$(mktemp -d /tmp/z_mod_status.XXXXXX)
+      z.dir.make path="$fixture/source"
+      z.dir.make path="$fixture/installed"
+      z.file.write path="$fixture/source/value" content=new
+      z.file.write path="$fixture/installed/value" content=old
+
+      z.install.mod.list._status source="$fixture/source" installed="$fixture/installed"
+
+      z.t.expect.reply update-available
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "fileの追加・削除がある場合"; {
+    for side in source installed; do
+      z.t.it "$side側だけにfileがあるとupdate-availableを返す"; {
+        local fixture=$(mktemp -d /tmp/z_mod_status.XXXXXX)
+        z.dir.make path="$fixture/source"
+        z.dir.make path="$fixture/installed"
+        z.file.write path="$fixture/$side/only" content=changed
+
+        z.install.mod.list._status source="$fixture/source" installed="$fixture/installed"
+
+        z.t.expect.reply update-available
+
+        z.dir.remove path="$fixture"
+      }
+    done
+  }
+
+  z.t.context "導入済みのmodが配布元にない場合"; {
+    z.t.it "installedを返す"; {
+      local fixture=$(mktemp -d /tmp/z_mod_status.XXXXXX)
+      z.dir.make path="$fixture/installed"
+
+      z.install.mod.list._status source="$fixture/missing" installed="$fixture/installed"
+
+      z.t.expect.reply installed
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "比較中に読み取りerrorが起きた場合"; {
+    z.t.it "更新ありと誤認せず失敗する"; {
+      local fixture=$(mktemp -d /tmp/z_mod_status.XXXXXX)
+      z.dir.make path="$fixture/source"
+      z.dir.make path="$fixture/installed"
+      z.t.mock name=diff behavior="return 2"
+
+      z.install.mod.list._status source="$fixture/source" installed="$fixture/installed" 2>/dev/null
+
+      z.t.expect.status.is.false
+
+      z.dir.remove path="$fixture"
+    }
+  }
+}
diff --git a/test/lib/install/mod/list/process_test.zsh b/test/lib/install/mod/list/process_test.zsh
new file mode 100644
index 0000000..d3cc35a
--- /dev/null
+++ b/test/lib/install/mod/list/process_test.zsh
@@ -0,0 +1,94 @@
+source "$z_main"
+
+z.t.describe "z.install.mod.list._fetch"; {
+  z.t.context "配布archiveを取得できる場合"; {
+    z.t.it "指定branchを一度取得してmod配布元を返す"; {
+      local fixture=$(mktemp -d /tmp/z_mod_fetch.XXXXXX)
+      z.dir.make path="$fixture/input/z-topic/mod/example"
+      z.dir.make path="$fixture/work"
+      z.file.write path="$fixture/input/z-topic/mod/example/value" content=remote
+      tar -czf "$fixture/archive.tar.gz" -C "$fixture/input" z-topic
+
+      z.t.mock name=curl behavior="cp \"$fixture/archive.tar.gz\" \"$fixture/work/source.tar.gz\""
+
+      z.install.mod.list._fetch dir="$fixture/work" branch=topic/change
+      local result_code=$?
+      local source_dir=$REPLY
+
+      z.t.mock.result name=curl
+      local call=$REPLY
+
+      z.t.expect "$result_code" 0
+      z.t.expect "$source_dir" "$fixture/work/z-topic/mod"
+      z.t.expect "$call" "-fLsS https://github.com/milkeclair/z/archive/refs/heads/topic/change.tar.gz -o $fixture/work/source.tar.gz"
+
+      z.file.read path="$source_dir/example/value"
+      z.t.expect.reply remote
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "取得に失敗した場合"; {
+    z.t.it "展開を行わず失敗する"; {
+      local fixture=$(mktemp -d /tmp/z_mod_fetch.XXXXXX)
+      local -a extracted=()
+      z.t.mock name=curl behavior="return 22"
+      z.t.mock name=tar behavior='extracted+=(called); return 0'
+
+      z.install.mod.list._fetch dir="$fixture" 2>/dev/null
+      local result_code=$?
+
+      z.t.expect "$result_code" 1 skip_unmock=true
+      z.t.expect "$extracted" ""
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "archiveが壊れている場合"; {
+    z.t.it "失敗する"; {
+      local fixture=$(mktemp -d /tmp/z_mod_fetch.XXXXXX)
+      z.t.mock name=curl behavior="z.file.write path=\"$fixture/source.tar.gz\" content=invalid"
+
+      z.install.mod.list._fetch dir="$fixture" 2>/dev/null
+
+      z.t.expect.status.is.false
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "mod directoryが含まれない場合"; {
+    z.t.it "一覧を空として扱わず失敗する"; {
+      local fixture=$(mktemp -d /tmp/z_mod_fetch.XXXXXX)
+      z.dir.make path="$fixture/input/z-main/lib"
+      z.dir.make path="$fixture/work"
+      tar -czf "$fixture/archive.tar.gz" -C "$fixture/input" z-main
+      z.t.mock name=curl behavior="cp \"$fixture/archive.tar.gz\" \"$fixture/work/source.tar.gz\""
+
+      z.install.mod.list._fetch dir="$fixture/work" 2>/dev/null
+
+      z.t.expect.status.is.false
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "配布元directoryが複数ある場合"; {
+    z.t.it "任意の配布元を選ばず失敗する"; {
+      local fixture=$(mktemp -d /tmp/z_mod_fetch.XXXXXX)
+      z.dir.make path="$fixture/input/one/mod"
+      z.dir.make path="$fixture/input/two/mod"
+      z.dir.make path="$fixture/work"
+      tar -czf "$fixture/archive.tar.gz" -C "$fixture/input" one two
+      z.t.mock name=curl behavior="cp \"$fixture/archive.tar.gz\" \"$fixture/work/source.tar.gz\""
+
+      z.install.mod.list._fetch dir="$fixture/work" 2>/dev/null
+
+      z.t.expect.status.is.false
+
+      z.dir.remove path="$fixture"
+    }
+  }
+}
diff --git a/test/lib/install/mod/process_test.zsh b/test/lib/install/mod/process_test.zsh
new file mode 100644
index 0000000..e4cd900
--- /dev/null
+++ b/test/lib/install/mod/process_test.zsh
@@ -0,0 +1,152 @@
+source "$z_main"
+
+z.t.describe "z.install.mod.list"; {
+  z.t.context "複数の導入状態が混在する場合"; {
+    z.t.it "名前順に重複なく表示して各状態を緑・オレンジ・赤にする"; {
+      local fixture=$(mktemp -d "/tmp/z mod list.XXXXXX")
+      local z_root="$fixture/installed"
+      local Z_INSTALL_BRANCH=topic/change
+      local work_dir="$fixture/work"
+      local fetch_calls=0
+      z.dir.make path="$fixture/source/alpha"
+      z.dir.make path="$fixture/source/beta"
+      z.dir.make path="$fixture/source/gamma"
+      z.dir.make path="$z_root/mod/alpha"
+      z.dir.make path="$z_root/mod/beta"
+      z.dir.make path="$z_root/mod/local-only"
+      z.file.write path="$fixture/source/alpha/value" content=new
+      z.file.write path="$z_root/mod/alpha/value" content=old
+      z.file.write path="$fixture/source/beta/value" content=same
+      z.file.write path="$z_root/mod/beta/value" content=same
+      z.file.write path="$fixture/source/gamma/mod.zsh" content="touch \"$fixture/executed\""
+
+      z.t.mock name=mktemp behavior="z.dir.make path=\"$work_dir\"; z.io \"$work_dir\""
+      z.t.mock name="z.install.mod.list._fetch" behavior="((fetch_calls++)); z.return \"$fixture/source\""
+
+      z.install.mod.list > "$fixture/output"
+      local result_code=$?
+      local result_reply=$REPLY
+      local output=$(< "$fixture/output")
+
+      z.t.mock.result name="z.install.mod.list._fetch"
+      local fetch_args=$REPLY
+
+      z.t.expect "$result_code" 0
+      z.t.expect "$result_reply" ""
+      z.t.expect "$fetch_calls" 1
+      z.t.expect "$fetch_args" "dir=$work_dir branch=topic/change"
+      z.t.expect "$output" $'\033[38;5;208malpha [update-available]\033[0m\n\033[32mbeta [installed]\033[0m\n\033[31mgamma [not-installed]\033[0m\n\033[32mlocal-only [installed]\033[0m'
+
+      z.dir.not.exists "$work_dir"
+      z.t.expect.status.is.true
+
+      z.file.not.exists "$fixture/executed"
+      z.t.expect.status.is.true
+
+      z.file.read path="$z_root/mod/alpha/value"
+      z.t.expect.reply old
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "導入済みmodがない場合"; {
+    z.t.it "公開modを赤色で表示する"; {
+      local fixture=$(mktemp -d /tmp/z_mod_list.XXXXXX)
+      local z_root="$fixture/installed"
+      z.dir.make path="$fixture/source/example"
+      z.t.mock name="z.install.mod.list._fetch" behavior="z.return \"$fixture/source\""
+
+      z.install.mod.list > "$fixture/output"
+      local result_code=$?
+      local output=$(< "$fixture/output")
+
+      z.t.expect "$result_code" 0
+      z.t.expect "$output" $'\033[31mexample [not-installed]\033[0m'
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "公開modも導入済みmodもない場合"; {
+    z.t.it "出力せず成功する"; {
+      local fixture=$(mktemp -d /tmp/z_mod_list.XXXXXX)
+      local z_root="$fixture/installed"
+      z.dir.make path="$fixture/source"
+      z.t.mock name="z.install.mod.list._fetch" behavior="z.return \"$fixture/source\""
+
+      z.install.mod.list > "$fixture/output"
+      local result_code=$?
+
+      z.t.expect "$result_code" 0
+      [[ ! -s "$fixture/output" ]]
+      z.t.expect.status.is.true
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "取得に失敗した場合"; {
+    z.t.it "誤った一覧を出さず作業directoryを片付ける"; {
+      local fixture=$(mktemp -d /tmp/z_mod_list.XXXXXX)
+      local z_root="$fixture/installed"
+      local work_dir="$fixture/work"
+      z.t.mock name=mktemp behavior="z.dir.make path=\"$work_dir\"; z.io \"$work_dir\""
+      z.t.mock name="z.install.mod.list._fetch" behavior="z.file.write path=\"$work_dir/partial\" content=partial; return 1"
+
+      z.install.mod.list > "$fixture/output" 2>/dev/null
+      local result_code=$?
+
+      z.t.expect "$result_code" 1
+      [[ ! -s "$fixture/output" ]]
+      z.t.expect.status.is.true
+
+      z.dir.not.exists "$work_dir"
+      z.t.expect.status.is.true
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "modの比較に失敗した場合"; {
+    z.t.it "状態を表示せず作業directoryを片付ける"; {
+      local fixture=$(mktemp -d /tmp/z_mod_list.XXXXXX)
+      local z_root="$fixture/installed"
+      local work_dir="$fixture/work"
+      z.dir.make path="$fixture/source/example"
+      z.dir.make path="$z_root/mod/example"
+      z.t.mock name=mktemp behavior="z.dir.make path=\"$work_dir\"; z.io \"$work_dir\""
+      z.t.mock name="z.install.mod.list._fetch" behavior="z.return \"$fixture/source\""
+      z.t.mock name=diff behavior="return 2"
+
+      z.install.mod.list > "$fixture/output" 2>/dev/null
+      local result_code=$?
+
+      z.t.expect "$result_code" 1
+      [[ ! -s "$fixture/output" ]]
+      z.t.expect.status.is.true
+
+      z.dir.not.exists "$work_dir"
+      z.t.expect.status.is.true
+
+      z.dir.remove path="$fixture"
+    }
+  }
+
+  z.t.context "作業directoryを確保できない場合"; {
+    z.t.it "取得を開始せず失敗する"; {
+      local fixture=$(mktemp -d /tmp/z_mod_list.XXXXXX)
+      local -a fetched=()
+      z.t.mock name=mktemp behavior="return 1"
+      z.t.mock name="z.install.mod.list._fetch" behavior='fetched+=(called); return 0'
+
+      z.install.mod.list > "$fixture/output" 2>/dev/null
+      local result_code=$?
+
+      z.t.expect "$result_code" 1 skip_unmock=true
+      z.t.expect "$fetched" ""
+
+      z.dir.remove path="$fixture"
+    }
+  }
+}
diff --git a/test/lib/str/process_test.zsh b/test/lib/str/process_test.zsh
index 57d9303..64a9d5c 100644
--- a/test/lib/str/process_test.zsh
+++ b/test/lib/str/process_test.zsh
@@ -9,6 +9,9 @@ z.t.describe "z.str.color"; {
       z.str.color "green"
       z.t.expect.reply $'\033[32m'
 
+      z.str.color "orange"
+      z.t.expect.reply $'\033[38;5;208m'
+
       z.str.color "yellow"
       z.t.expect.reply $'\033[33m'