Escrow the chain itself enforces
You will understand how an output can be locked by policy rather than by a third party, and what that costs in flexibility.
The problem
Somebody has to hold the money in the middle.
Any exchange between strangers has a moment where one side has paid and the other has not delivered. The usual answer is a trusted third party who holds the funds, which works and which replaces the risk of a counterparty with the risk of the escrow agent. This chain answers differently: the rules hold the funds.
Policy-locked outputs
An output that cannot be spent until its condition is met.
The escrow is a property of the output itself: it carries a policy, and validation refuses any spend that does not satisfy it. No agent holds anything, because there is nothing to hold — the coins are on chain and the only thing that can release them is the rule that was written when they were locked.
What it costs
A rule cannot be reasoned with.
A human escrow agent can be persuaded that a delivery was substantially complete. A policy cannot: if the condition is not met exactly, the funds stay locked, and a badly written condition can lock them permanently. That rigidity is the price of removing the agent, and it is why the escrow path in this chain is deliberately narrow and heavily tested.
Reachability
A rule nobody can reach is worse than no rule.
This chain shipped an escrow that four separate validation layers each refused for different reasons, so a correctly formed escrow could never be spent — a lock with no key, which would have frozen every coin placed in it. It is one rule now, in one place, and there is a command to build and inspect an escrow before you fund it. Test the release path on testnet first, every time.
In short
- The escrow is a property of the output: validation refuses a spend that fails the policy.
- No agent holds the funds, so there is no agent to trust or to fail.
- A policy cannot be negotiated with, and a badly written one locks the coins for good.
- Build and inspect the escrow, and exercise the release path on testnet, before funding it.