33. Open an asset on a satellite

Opening an asset on a satellite makes the token on the reference chain and its T-REX Lite on that chain able to exchange messages, and makes the compliance able to authorize transfers there. A token opens no chain by default. The Issuer opens each satellite explicitly, with a route, a peer when one is needed, the two time windows that govern validations, and the deployment of T-REX Lite on the satellite. Until this is done, no position can be delegated to that chain and no transfer can be authorized on it.

At a glance

Triggered by	Issuer
Actors	Issuer, Network governance, Platform
Contracts	Token, ModularCompliance, TrustedGatewayRegistry (read only), the T-REX Lite factory of the satellite
Preconditions	The token suite is deployed and commissioned (see 01 and 25); the callers hold IDENTITY_MANAGER and COMPLIANCE_MANAGER in the asset's domain; a gateway that reaches the satellite is in the TrustedGatewayRegistry; a T-REX Lite factory exists on the satellite
Result	Token.isChainOpen(chainKey) is true, T-REX Lite exists on the satellite, and the compliance can issue validations for that chain

Actors and roles

Actor	Role in this flow	What they hold
Issuer	Chooses the gateway, registers the peer and sets the windows.	IDENTITY_MANAGER on the Token. COMPLIANCE_MANAGER on the ModularCompliance
Network governance	Has vetted the gateway beforehand. Does not transact in this flow.	INTEROP_MANAGER on the TrustedGatewayRegistry
Platform	Prepares the chain identifiers, relays the calls and confirms the result.	Whatever keys the Issuer has authorized

Sequence

Step by step

Step 1. Prepare the settings

Who: Platform, on behalf of the Issuer

Call: Off-chain, using read calls

Before the call: The Issuer has chosen the satellite and the messaging provider that carries the asset's traffic to it.

What happens: The Platform gathers four things.

Setting	How it is obtained
The chain	Its ERC-7930 chain type and chain reference. For an EVM chain, the type is 0x0000 and the reference is the chain id in its shortest big-endian form, with no leading zero byte.
The gateway	The address, on the reference chain, of the ERC-7786 gateway of the chosen provider for that chain. TrustedGatewayRegistry.isTrusted(gateway) must be true.
The peer	The address of the asset's T-REX Lite on the satellite. On an EVM satellite where T-REX Lite sits at the token's own address, nothing is needed.
The windows	The validity window of the asset, and the reconciliation window for this chain: the longest time that chain takes to finalize a transaction and for its message to reach the reference chain, with a margin.

What changes: Nothing on-chain.

Step 2. Set the route

Who: Issuer (IDENTITY_MANAGER)

Call: Token.setRoute(chainType, chainReference, gateway)

Before the call: Step 1 is done.

What the contract checks:

1. The caller holds IDENTITY_MANAGER in the asset's domain. Otherwise the call reverts with AccessManagedUnauthorized.

2. The gateway is trusted by the network at this moment. Otherwise GatewayNotTrusted.

3. The chain reference is not empty and, for an EVM chain, has no leading zero byte. Otherwise InvalidChainReference.

What changes: The first time the token sees this chain, it records the chain type and reference behind the chain key and emits ChainRegistered(chainKey, chainType, chainReference). It records the gateway as the route for that chain and emits RouteSet(chainKey, gateway). The chainKey in these events is the identifier used in every later call for this chain.

Step 3. Register the peer

Only when T-REX Lite is not at the token's own address: on a non-EVM satellite, or when the addresses differ.

Who: Issuer (IDENTITY_MANAGER)

Call: Token.setPeer(chainKey, peer)

Before the call: The Platform has encoded the address of T-REX Lite as an ERC-7930 interoperable address of that chain.

What the contract checks:

1. The caller holds IDENTITY_MANAGER in the asset's domain. Otherwise AccessManagedUnauthorized.

2. The peer is a canonical ERC-7930 address with an account part and no trailing bytes. Otherwise InvalidPeer.

3. The chain of the peer is the chain named by chainKey. Otherwise PeerChainMismatch.

What changes: The token records the peer for that chain and emits PeerSet(chainKey, peer). The peer is the only recipient the token sends to on that chain and the only author it accepts messages from.

Step 4. Set the windows

Who: Issuer (COMPLIANCE_MANAGER)

Call: ModularCompliance.setDefaultValidityWindow(duration), once for the asset, and ModularCompliance.setReconciliationWindow(chainKey, duration), for this chain

Before the call: The durations are decided, in seconds.

What the contract checks:

1. The caller holds COMPLIANCE_MANAGER in the asset's domain. Otherwise AccessManagedUnauthorized.

2. The duration is not zero. Otherwise ZeroDuration.

What changes: The compliance records the validity window and emits DefaultValidityWindowSet(duration). It records the reconciliation window of the chain and emits ReconciliationWindowSet(chainKey, duration). A validation issued from now on expires one validity window after its issuance, and its reservation is kept one reconciliation window longer.

Step 5. Deploy T-REX Lite on the satellite

Who: Issuer

Call: [[TBC: the call on the reference chain that has T-REX Lite deployed on a satellite]]

Before the call: The route is set, so that a message can reach the satellite.

What happens: A message goes through the ERC-7786 gateway to the T-REX Lite factory of the satellite. The factory deploys T-REX Lite for the asset, with the token on the reference chain as its peer. On an EVM satellite, T-REX Lite is deployed at the token's own address. The Issuer does not deploy anything on the satellite itself.

What changes: On the satellite, T-REX Lite and its compliance contract exist for the asset, with no supply. On the reference chain, nothing.

Step 6. Confirm the chain is open

Who: Platform

Call: Off-chain, using read calls

Before the call: Steps 2 to 5 are confirmed.

What happens: The Platform reads Token.isChainOpen(chainKey), which must be true, and Token.peerFor(chainKey), which must be the address of T-REX Lite. It reads ModularCompliance.reconciliationWindowOf(chainKey) and ModularCompliance.defaultValidityWindow(), which must not be zero, and ModularCompliance.isIssuancePaused(chainKey), which must be false. It confirms on the satellite that T-REX Lite exists at the address of the peer.

What changes: Nothing on-chain.

State after the flow

• Token.routeFor(chainKey) returns the gateway, and Token.chainOf(chainKey) returns the chain type and reference.

• Token.peerFor(chainKey) returns the registered peer, or the token's own address on an EVM chain where none was registered.

• Token.isChainOpen(chainKey) is true.

• ModularCompliance.defaultValidityWindow() and ModularCompliance.reconciliationWindowOf(chainKey) are set.

• T-REX Lite is deployed on the satellite, with the token as its peer.

• No position has moved. Nothing is bridged yet.

Failure modes

Symptom	Cause	Fix
Reverts with AccessManagedUnauthorized	The caller does not hold the role of the function: IDENTITY_MANAGER for the route and the peer, COMPLIANCE_MANAGER for the windows (check 1 of steps 2 to 4)	Grant the role: 25
setRoute reverts with GatewayNotTrusted	The gateway is not in the TrustedGatewayRegistry (step 2, check 2)	Use a gateway the network has vetted. Adding one is a decision of Network governance
setRoute reverts with InvalidChainReference	The chain reference is empty, or has a leading zero byte for an EVM chain (step 2, check 3)	Encode the chain id in its shortest form
setPeer reverts with InvalidPeer, or on the address encoding	The peer is not a canonical ERC-7930 address, has no account part, or has trailing bytes (step 3, check 2)	Encode the chain and the address in canonical form
setPeer reverts with PeerChainMismatch	The peer is on another chain than the one chainKey names (step 3, check 3)	Take chainKey from the RouteSet event of that chain
setPeer with an empty value reverts with ChainNotRegistered	Restoring the default peer on a chain the token has never seen	Set the route first
A window call reverts with ZeroDuration	The duration is zero (step 4, check 2)	Pass a positive duration
isChainOpen is false after step 2	No peer is known: the satellite is not an EVM chain, and none was registered	Register the peer (step 3)
isChainOpen was true and is now false	The network removed the gateway from the registry	Set a route through another trusted gateway
The chain is open and a validation request reverts with ReconciliationWindowNotSet or ValidityWindowNotSet	A window was not set	Do step 4
The chain is open and validations are never executed	T-REX Lite is not deployed on the satellite, or not at the address of the peer	Do step 5. On a chain where the address differs, register the peer (step 3)

Common misunderstandings

Wrong: "Once the network supports a chain, every asset is available there."

Right: The network vets gateways. Each Issuer opens its own asset, chain by chain. A token sends nothing to, and accepts nothing from, a chain it was not opened for.

Wrong: "The Issuer can route through any bridge it likes."

Right: A route can only name a gateway in the network's TrustedGatewayRegistry. The Issuer chooses among vetted gateways. It cannot point its token at a list of its own.

Wrong: "Opening a satellite moves tokens there."

Right: Opening a chain moves nothing. Positions reach a satellite by a movement that starts on the reference chain: a delegation-out by the holder, a transfer in one step to a recipient's satellite wallet, or a mint by an agent directly to a satellite wallet. Until then nothing is bridged and nothing can be transferred there. See Movement types.

Wrong: "The reconciliation window is how long a transfer has to execute."

Right: That is the validity window. The reconciliation window is the extra time the register waits, after a validation expires, for the report of a transfer that executed just in time. It is sized on the satellite's finality and on the message latency, with a margin.

Integration notes

• Take chainKey from the ChainRegistered or RouteSet event. It is the hash of the ERC-7930 chain identifier, and every per-chain call uses it.

• Choose the reconciliation window conservatively. A window that is too short turns ordinary settlements into late reconciliations.

• The windows are read when a validation is issued. Changing them later affects new validations only.

• Changing the route later is safe. A validation already sent is settled through the gateway it went out by, as long as the network still trusts that gateway.

• To close a satellite, set its route to the zero address. The token then sends nothing to the chain and refuses burn proofs from it. Settlements of validations already sent are still accepted through the gateway that carried them. To stop authorizing new transfers there while still recording those already executed, call ModularCompliance.setIssuancePaused(chainKey, true).

• Grant VALIDATION_KEEPER to the keeper before the first transfer is authorized: 25. The T-REX Network operates the keeper that discards expired validations.

• The caller of a transaction that sends a cross-chain message pays for the message, directly or through a paymaster. Opening a chain costs the Issuer its own transactions and the deployment message.

• Holders link their wallets on the satellite to their ONCHAINID before they delegate out: 07.

Related flows

• 30 Delegate a position out to a satellite : how a holder takes its own position to the satellite once it is open

• 31 Transfer on a satellite : what the windows govern

• 35 Discard or resolve a validation : the keeper's work once transfers are authorized

• 36 Handle a late reconciliation or a halt : pausing and closing a chain

• 26 Authorize spenders : listing the venues of the satellite

• 07 Link a wallet to an ONCHAINID : linking a wallet that lives on the satellite