cdx - Interactive MCP server selector for Codex CLI. Uses fzf for multi-select. Works on Linux/macOS.

cdx

#!/usr/bin/env zsh
# cdx - Codex CLI launcher with interactive MCP server selection
# Works on Linux and macOS

set -euo pipefail

config="${CODEX_CONFIG_PATH:-$HOME/.codex/config.toml}"

if [[ ! -f "$config" ]]; then
  echo "Missing config file: $config" >&2
  exit 1
fi

# Extract MCP server names, strip any quotes
names=$(
  grep -E '^\[mcp_servers\.' "$config" \
    | grep -v '\.env\]' \
    | sed 's/\[mcp_servers\.\([^]]*\)\]/\1/' \
    | sed 's/^"//; s/"$//' \
    | sort -u
)

if [[ -z "$names" ]]; then
  echo "No mcp_servers found in $config" >&2
  exit 1
fi

# Select servers via fzf
if command -v fzf >/dev/null 2>&1; then
  selected=$(
    print -r -- "$names" | fzf -m \
      --layout=reverse \
      --prompt="Select MCP servers (TAB=toggle, ENTER=confirm): "
  ) || {
    echo "No MCP servers selected; aborting." >&2
    exit 1
  }
else
  echo "fzf not found; enabling all servers" >&2
  selected="$names"
fi

# Build lookup of selected servers
typeset -A selected_map
while IFS= read -r srv; do
  [[ -n "$srv" ]] && selected_map[$srv]=1
done <<< "$selected"

# Backup config
cp "$config" "${config}.bak"

# Rewrite config:
# - Always inject an `enabled = true/false` line immediately after each [mcp_servers.<name>] header
# - Remove any existing enabled= lines within that server block to avoid duplicates
awk -v selected="${(kj:,:)selected_map}" '
BEGIN {
  n = split(selected, arr, ",")
  for (i = 1; i <= n; i++) sel[arr[i]] = 1
  in_mcp = 0
  current_server = ""
}

/^\[mcp_servers\.[^.]+\]$/ {
  # entering a top-level mcp server block
  match($0, /\[mcp_servers\.([^]]+)\]/, m)
  current_server = m[1]
  gsub(/^"|"$/, "", current_server)

  in_mcp = 1
  print

  # ALWAYS write enabled line (even if it didn’t exist before)
  if (current_server in sel) print "enabled = true"
  else                      print "enabled = false"

  next
}

/^\[/ {
  # entering any other table => stop treating as “inside current mcp server”
  in_mcp = 0
  current_server = ""
  print
  next
}

in_mcp && /^enabled[[:space:]]*=/ {
  # drop any existing enabled lines (we already emitted ours)
  next
}

{ print }
' "$config" > "${config}.tmp" && mv "${config}.tmp" "$config"

# Build display list
enabled_display="${(j:, :)${(f)selected}}"

# Report and launch
echo "✓ Enabled: ${enabled_display:-none}"
exec codex "$@"