PURRS

Can refuse liquidity removals. Whoever controls the hook controls the exit for LPs.

• takes a cut of swaps
  The hook may add or remove value on every swap. Our fills for this pool come from the on-chain quoter, so whatever it takes is already in the number you see.
• can block LP withdrawals
  The hook runs before any liquidity removal and may refuse it. On launchpad hooks the hook itself is the only LP; for anyone else this is the exit being controlled by someone else.
• gates who can add liquidity
  Usually means the hook (or its launchpad) is the sole LP — no one else can dilute or front-run the curve. It also means you cannot LP here.
• controls pool creation
  Only pools the hook agrees to can be created with it — the launchpad pattern.
• handles donations
  Reacts to direct donations into the pool (rare).