diff --git a/CLAUDE.md b/CLAUDE.md
index f2d2d52..de5be48 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -33,7 +33,7 @@ The `install.sh` script automates initial setup (clone, build, create container,
 
 1. **Git identity** — name and email (skipped if already configured)
 2. **GitHub CLI auth** — persisted to `/workspace/.squarebox/gh` across rebuilds
-3. **AI coding assistant** — Claude Code, OpenCode, or both
+3. **AI coding assistant** — Claude Code, GitHub Copilot CLI, Google Gemini CLI, OpenAI Codex CLI, OpenCode (any combination)
 4. **Text editors** — micro, edit (Microsoft), fresh, helix, nvim (nano is always available)
 5. **SDKs** — Node.js (via nvm), Python (via uv), Go, .NET
 
diff --git a/README.md b/README.md
index 67b25db..763b46a 100644
--- a/README.md
+++ b/README.md
@@ -66,13 +66,18 @@ What's included
 
 ### AI Coding Assistants (optional)
 
-Installed during first-run setup. Choose one or both:
+Installed during first-run setup. Choose any combination:
 
 | Name | Language | Description |
 |------|----------|-------------|
 | [Claude Code](https://github.com/anthropics/claude-code) | TypeScript | AI coding assistant |
+| [GitHub Copilot CLI](https://github.com/githubnext/github-copilot-cli) | TypeScript | GitHub Copilot in the terminal * |
+| [Google Gemini CLI](https://github.com/google-gemini/gemini-cli) | TypeScript | Google Gemini in the terminal * |
+| [OpenAI Codex CLI](https://github.com/openai/codex) | TypeScript | OpenAI Codex in the terminal * |
 | [opencode](https://github.com/anomalyco/opencode) | Go | AI coding TUI |
 
+\* Requires Node.js (auto-installed if needed).
+
 ### Text Editors (optional)
 
 Installed during first-run setup. Nano is always available as the default editor.
@@ -102,7 +107,7 @@ Inspired by [Omarchy](https://omarchy.com).
 | `..` | `cd ..` | Go up one directory |
 | `...` | `cd ../..` | Go up two directories |
 | `....` | `cd ../../..` | Go up three directories |
-| `c` | `claude` or `opencode` | Launch selected AI assistant |
+| `c` | first selected AI tool | Launch selected AI assistant |
 | `g` | `git` | Git shorthand |
 | `gcm` | `git commit -m` | Commit with message |
 | `gcam` | `git commit -a -m` | Stage all and commit |
@@ -179,6 +184,9 @@ First-run selections add to that:
 | Component | Adds |
 |-----------|------|
 | Claude Code | ~300 MB |
+| GitHub Copilot CLI | ~50 MB |
+| Google Gemini CLI | ~50 MB |
+| OpenAI Codex CLI | ~50 MB |
 | OpenCode | ~30 MB |
 | micro / edit | ~12 / ~7 MB |
 | fresh / helix / nvim | ~10 / ~80 / ~45 MB |
@@ -195,7 +203,8 @@ Security
 
 All binary tools are pinned to specific versions and verified against SHA256
 checksums at build time. Third-party install scripts (Claude Code, uv, .NET)
-manage their own binary verification.
+manage their own binary verification. npm-based AI tools (Copilot CLI, Gemini
+CLI, Codex CLI) use npm's built-in integrity verification.
 
 For the full trust model (what `install.sh` does on your machine, how each
 layer is verified, and how to inspect the script before running it) see
diff --git a/setup.sh b/setup.sh
index 9aaf253..366b659 100755
--- a/setup.sh
+++ b/setup.sh
@@ -112,62 +112,81 @@ mkdir -p /workspace/.squarebox ~/.local/bin
 ai_prev=""
 if [ -f "$AI_CONFIG" ]; then
 	ai_prev=$(cat "$AI_CONFIG")
-fi
-
-if $INTERACTIVE; then
+	# Migrate legacy single-choice values
 	case "$ai_prev" in
-		claude)   ai_default_label="Claude Code" ;;
-		opencode) ai_default_label="OpenCode" ;;
-		both)     ai_default_label="Both" ;;
-		*)        ai_default_label="" ;;
+		both) ai_prev="claude,opencode" ;;
 	esac
+fi
 
+if $INTERACTIVE; then
 	echo
 	if $HAS_GUM; then
-		gum_args=(--header "Choose your AI coding assistant:")
-		[ -n "$ai_default_label" ] && gum_args+=(--selected "$ai_default_label")
-		ai_label=$(gum choose "${gum_args[@]}" \
-			"Claude Code" "OpenCode" "Both") || true
-		case "$ai_label" in
-			"Claude Code") ai_choice="claude" ;;
-			"OpenCode")    ai_choice="opencode" ;;
-			"Both")        ai_choice="both" ;;
-			*)             echo "No selection, defaulting to Claude Code"; ai_choice="claude" ;;
-		esac
+		# Build --selected from previously saved AI tools
+		gum_selected=""
+		for ai in $(echo "$ai_prev" | tr ',' ' '); do
+			case "$ai" in
+				claude)   gum_selected="${gum_selected:+$gum_selected,}Claude Code" ;;
+				copilot)  gum_selected="${gum_selected:+$gum_selected,}GitHub Copilot CLI" ;;
+				gemini)   gum_selected="${gum_selected:+$gum_selected,}Google Gemini CLI" ;;
+				codex)    gum_selected="${gum_selected:+$gum_selected,}OpenAI Codex CLI" ;;
+				opencode) gum_selected="${gum_selected:+$gum_selected,}OpenCode" ;;
+			esac
+		done
+		gum_args=(--no-limit --header "Select AI coding assistants (space=toggle, enter=confirm):")
+		[ -n "$gum_selected" ] && gum_args+=(--selected "$gum_selected")
+		selected=$(gum choose "${gum_args[@]}" \
+			"Claude Code" "GitHub Copilot CLI" "Google Gemini CLI" \
+			"OpenAI Codex CLI" "OpenCode") || true
+		ai_choice=""
+		while IFS= read -r line; do
+			case "$line" in
+				"Claude Code")        ai_choice="${ai_choice:+$ai_choice,}claude" ;;
+				"GitHub Copilot CLI") ai_choice="${ai_choice:+$ai_choice,}copilot" ;;
+				"Google Gemini CLI")  ai_choice="${ai_choice:+$ai_choice,}gemini" ;;
+				"OpenAI Codex CLI")   ai_choice="${ai_choice:+$ai_choice,}codex" ;;
+				"OpenCode")           ai_choice="${ai_choice:+$ai_choice,}opencode" ;;
+			esac
+		done <<< "$selected"
 	else
-		echo "Choose your AI coding assistant:"
-		if [ "$ai_prev" = "claude" ];   then echo "  1) Claude Code [current]"; else echo "  1) Claude Code"; fi
-		if [ "$ai_prev" = "opencode" ]; then echo "  2) OpenCode [current]";    else echo "  2) OpenCode"; fi
-		if [ "$ai_prev" = "both" ];     then echo "  3) Both [current]";        else echo "  3) Both"; fi
-		read -rp "Selection [1/2/3]: " selection
-		if [ -z "$selection" ] && [ -n "$ai_prev" ]; then
+		echo "Select AI coding assistants (comma-separated, 'all', or press Enter to skip):"
+		for ai_item in "1:claude:Claude Code" "2:copilot:GitHub Copilot CLI" "3:gemini:Google Gemini CLI" "4:codex:OpenAI Codex CLI" "5:opencode:OpenCode"; do
+			num="${ai_item%%:*}"; rest="${ai_item#*:}"; key="${rest%%:*}"; label="${rest#*:}"
+			if [[ ",$ai_prev," == *",${key},"* ]]; then
+				echo "  ${num}) ${label} [installed]"
+			else
+				echo "  ${num}) ${label}"
+			fi
+		done
+		read -rp "Selection [1,2,3,4,5/all/skip]: " ai_selection
+		if [ -z "$ai_selection" ] && [ -n "$ai_prev" ]; then
 			ai_choice="$ai_prev"
 		else
-			case "$selection" in
-				1) ai_choice="claude" ;;
-				2) ai_choice="opencode" ;;
-				3) ai_choice="both" ;;
-				*) echo "Invalid selection, defaulting to Claude Code"; ai_choice="claude" ;;
-			esac
+			ai_choice=""
+			if [ "$ai_selection" = "all" ]; then
+				ai_choice="claude,copilot,gemini,codex,opencode"
+			elif [ -n "$ai_selection" ]; then
+				for item in $(echo "$ai_selection" | tr ',' ' '); do
+					case "$item" in
+						1) ai_choice="${ai_choice:+$ai_choice,}claude" ;;
+						2) ai_choice="${ai_choice:+$ai_choice,}copilot" ;;
+						3) ai_choice="${ai_choice:+$ai_choice,}gemini" ;;
+						4) ai_choice="${ai_choice:+$ai_choice,}codex" ;;
+						5) ai_choice="${ai_choice:+$ai_choice,}opencode" ;;
+					esac
+				done
+			fi
 		fi
 	fi
 	echo "$ai_choice" > "$AI_CONFIG"
 elif [ -n "$ai_prev" ]; then
 	ai_choice="$ai_prev"
-	echo "Installing AI tool: $ai_choice (from previous selection)"
+	echo "Installing AI tools: $ai_choice (from previous selection)"
 else
 	echo "Defaulting to Claude Code (non-interactive)"
 	ai_choice="claude"
 	echo "$ai_choice" > "$AI_CONFIG"
 fi
 
-if [ "$ai_choice" = "claude" ] || [ "$ai_choice" = "both" ]; then
-	echo "Installing Claude Code..."
-	# Trust boundary: the Claude Code install script manages its own binary
-	# fetching and verification. We rely on HTTPS for script integrity.
-	curl -fsSL https://claude.ai/install.sh | bash
-fi
-
 # Pinned versions — update via: scripts/update-versions.sh
 OPENCODE_VERSION="1.3.15"
 MICRO_VERSION="2.0.15"
@@ -185,27 +204,115 @@ for _var in OPENCODE_VERSION MICRO_VERSION EDIT_VERSION EDIT_ASSET_VERSION FRESH
 	fi
 done
 
-if [ "$ai_choice" = "opencode" ] || [ "$ai_choice" = "both" ]; then
-	if command -v opencode &>/dev/null; then
-		echo "OpenCode already installed, skipping."
-	else
-		echo "Installing OpenCode v${OPENCODE_VERSION}..."
-		sb_install opencode "$OPENCODE_VERSION"
+# Pinned SDK versions needed early (for npm-based AI tools)
+NVM_VERSION="0.40.3"
+
+# SDK path setup file (create if missing, preserve on retry)
+touch ~/.squarebox-sdk-paths
+
+install_node() {
+	if command -v node &>/dev/null; then echo "Node.js already installed, skipping."; return 0; fi
+	rm -rf "$HOME/.nvm"
+	echo "Installing Node.js (via nvm v${NVM_VERSION})..."
+	curl -fsSo /tmp/nvm-install.sh "https://raw.githubusercontent.com/nvm-sh/nvm/v${NVM_VERSION}/install.sh"
+	verify_checksum /tmp/nvm-install.sh "nvm-install-v${NVM_VERSION}.sh"
+	bash /tmp/nvm-install.sh
+	rm /tmp/nvm-install.sh
+	export NVM_DIR="$HOME/.nvm"
+	# shellcheck source=/dev/null
+	[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"
+	# Node.js binary verification is handled by nvm
+	nvm install --lts
+	if ! grep -q 'NVM_DIR' ~/.squarebox-sdk-paths 2>/dev/null; then
+		cat <<'PATHS' >> ~/.squarebox-sdk-paths
+export NVM_DIR="$HOME/.nvm"
+[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"
+PATHS
 	fi
-fi
+	if ! command -v node &>/dev/null; then
+		echo "Error: Node.js binary not found after installation" >&2
+		exit 1
+	fi
+}
 
-# Set aliases based on selection
-{
-	if [ "$ai_choice" = "claude" ]; then
-		echo "alias c='claude'"
-		echo "alias claude-yolo='claude --dangerously-skip-permissions'"
-	elif [ "$ai_choice" = "opencode" ]; then
-		echo "alias c='opencode'"
-		echo "alias opencode-yolo='opencode --dangerously-skip-permissions'"
+# Ensure Node.js is available for npm-based AI tools
+ensure_node_for_npm() {
+	if command -v node &>/dev/null; then return 0; fi
+	echo "Installing Node.js (required for npm-based AI tools)..."
+	install_node
+	# Ensure node/npm are available in this session
+	export NVM_DIR="$HOME/.nvm"
+	# shellcheck source=/dev/null
+	[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"
+	# Persist Node.js in SDK config so it survives rebuilds
+	local sdk_cfg="/workspace/.squarebox/sdks"
+	if [ -f "$sdk_cfg" ]; then
+		local sdk_current
+		sdk_current=$(cat "$sdk_cfg")
+		if [[ ",$sdk_current," != *",node,"* ]] && [ "$sdk_current" != "node" ]; then
+			echo "${sdk_current:+$sdk_current,}node" > "$sdk_cfg"
+		fi
 	else
-		echo "alias claude-yolo='claude --dangerously-skip-permissions'"
-		echo "alias opencode-yolo='opencode --dangerously-skip-permissions'"
+		echo "node" > "$sdk_cfg"
 	fi
+}
+
+install_copilot() {
+	if command -v github-copilot-cli &>/dev/null; then echo "GitHub Copilot CLI already installed, skipping."; return 0; fi
+	ensure_node_for_npm
+	echo "Installing GitHub Copilot CLI..."
+	npm install -g @githubnext/github-copilot-cli
+}
+
+install_gemini() {
+	if command -v gemini &>/dev/null; then echo "Google Gemini CLI already installed, skipping."; return 0; fi
+	ensure_node_for_npm
+	echo "Installing Google Gemini CLI..."
+	npm install -g @google/gemini-cli
+}
+
+install_codex() {
+	if command -v codex &>/dev/null; then echo "OpenAI Codex CLI already installed, skipping."; return 0; fi
+	ensure_node_for_npm
+	echo "Installing OpenAI Codex CLI..."
+	npm install -g @openai/codex
+}
+
+for ai_tool in $(echo "$ai_choice" | tr ',' ' '); do
+	case "$ai_tool" in
+		claude)
+			echo "Installing Claude Code..."
+			# Trust boundary: the Claude Code install script manages its own binary
+			# fetching and verification. We rely on HTTPS for script integrity.
+			curl -fsSL https://claude.ai/install.sh | bash
+			;;
+		opencode)
+			if command -v opencode &>/dev/null; then
+				echo "OpenCode already installed, skipping."
+			else
+				echo "Installing OpenCode v${OPENCODE_VERSION}..."
+				sb_install opencode "$OPENCODE_VERSION"
+			fi
+			;;
+		copilot)  install_copilot ;;
+		gemini)   install_gemini ;;
+		codex)    install_codex ;;
+	esac
+done
+
+# Set aliases based on selection — c maps to first selected tool in priority order
+{
+	c_target=""
+	for ai_tool in claude copilot gemini codex opencode; do
+		if [[ ",$ai_choice," == *",$ai_tool,"* ]]; then
+			[ -z "$c_target" ] && c_target="$ai_tool"
+			case "$ai_tool" in
+				claude)   echo "alias claude-yolo='claude --dangerously-skip-permissions'" ;;
+				opencode) echo "alias opencode-yolo='opencode --dangerously-skip-permissions'" ;;
+			esac
+		fi
+	done
+	[ -n "$c_target" ] && echo "alias c='$c_target'"
 } > ~/.squarebox-ai-aliases
 
 # Text editors
@@ -468,44 +575,17 @@ else
 	echo "$sdk_list" > "$SDK_CONFIG"
 fi
 
-# SDK path setup file (create if missing, preserve on retry)
-touch ~/.squarebox-sdk-paths
-
 # Pinned versions — update via: scripts/update-versions.sh
-NVM_VERSION="0.40.3"
 GO_VERSION="go1.26.1"
 
-for _var in NVM_VERSION GO_VERSION; do
+for _var in GO_VERSION; do
 	if [ -z "${!_var:-}" ]; then
 		echo "Error: ${_var} is empty or unset" >&2
 		exit 1
 	fi
 done
 
-install_node() {
-	if command -v node &>/dev/null; then echo "Node.js already installed, skipping."; return 0; fi
-	rm -rf "$HOME/.nvm"
-	echo "Installing Node.js (via nvm v${NVM_VERSION})..."
-	curl -fsSo /tmp/nvm-install.sh "https://raw.githubusercontent.com/nvm-sh/nvm/v${NVM_VERSION}/install.sh"
-	verify_checksum /tmp/nvm-install.sh "nvm-install-v${NVM_VERSION}.sh"
-	bash /tmp/nvm-install.sh
-	rm /tmp/nvm-install.sh
-	export NVM_DIR="$HOME/.nvm"
-	# shellcheck source=/dev/null
-	[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"
-	# Node.js binary verification is handled by nvm
-	nvm install --lts
-	if ! grep -q 'NVM_DIR' ~/.squarebox-sdk-paths 2>/dev/null; then
-		cat <<'PATHS' >> ~/.squarebox-sdk-paths
-export NVM_DIR="$HOME/.nvm"
-[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"
-PATHS
-	fi
-	if ! command -v node &>/dev/null; then
-		echo "Error: Node.js binary not found after installation" >&2
-		exit 1
-	fi
-}
+# install_node is defined earlier (needed by npm-based AI tools)
 
 install_python() {
 	if command -v uv &>/dev/null; then echo "uv already installed, skipping."; return 0; fi