Innate Spellcasting. The couatl's spellcasting ability is Charisma (spell save DC 11). It can innately cast the following spells, requiring only verbal components:
At will: detect magic, detect thoughts
Magic Weapons. The couatl's weapon attacks are considered magical.
Shielded Mind. The couatl is immune to any effect that would sense its emotions or read its thoughts.
Tail Attack. Melee Weapon Attack: +9 to hit, reach 5 ft., one creature. Hit: 13 (1d10 + 7) bludgeoning damage,
Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one creature. Hit: 10 (1d8 + 6) piercing damage, and the target must succeed on a DC 15 Constitution saving throw or be poisoned for 24 hours. Until this poison ends, the target is unconscious. Another creature can use an action to shake the target awake.
Constrict. Melee Weapon Attack: +8 to hit, reach 10 ft., one Large or smaller creature. Hit: 14 (2d8 + 6) bludgeoning damage, and the target is grappled (escape DC 15). Until this grapple ends, the target is restrained, and the couatl can't constrict another target.