Caliber Mailbox

A Caliber Mailbox is deployed alongside every Spoke Caliber. It is the Machine's local endpoint on the spoke chain: from the Caliber's perspective, the Mailbox stands in for the Machine, and it absorbs all the chain-specific logic so the Caliber behaves identically on every chain.

It plays three roles.

1. Liquidity gateway

The Mailbox controls the spoke side's set of bridge adapters and is the contract through which capital is sent to and received from the Hub Machine. It is the spoke-side counterpart to the Machine's hub-side bridging, executing the same four-step transfer and tracking pending in- and out-bound amounts per token.

2. Governance endpoint

Mirroring the Machine on the Hub Chain, the Mailbox exposes the per-strategy roles (Operator, Risk Manager, Security Council, …) to its Caliber, so the same permission model (including Recovery Mode) applies on the spoke. Recovery Mode is per-chain: it must be triggered on each spoke's Mailbox independently.

3. Accounting source

The Mailbox exposes the view function that the Chainlink CRE workflow reads to build the spoke's accounting snapshot: the Caliber's net AUM, pending bridge amounts, and the block context used for freshness checks. This is how the spoke's value reaches the Machine for total-AUM computation.