You can use a Free Action when you deal damage with the weapon to deal Poison damage instead of the weapon’s normal damage type.
When you deal Poison damage with the weapon, you can spend 1 charge of Inspiration or Mana Flux to inflict the Venom condition on the target.
When you deal Poison damage with the weapon, you can spend 1 charge of Inspiration or Mana Flux to inflict 1d6 Persistent Damage (Poison) per Tier of the weapon on the target.