> For the complete documentation index, see [llms.txt](https://plimsoll-protocol.gitbook.io/plimsoll-protocol-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://plimsoll-protocol.gitbook.io/plimsoll-protocol-docs/guides/integrators.md).

# For protocol integrators

Lending pools, vaults, routers and payment contracts can refuse an asset that is under-backed or whose figures are out of date, with one cross-contract call.

## Choose your thresholds

| Parameter  | Typical value      | Meaning                                          |
| ---------- | ------------------ | ------------------------------------------------ |
| `min_bps`  | `10000`            | Reserves must cover 100% of supply               |
| `max_age`  | `604800`           | Supply snapshot and report both under 7 days old |
| `min_tier` | `2` (IssuerSigned) | Ignore transcribed-only figures                  |

Stricter settings are safer and fail more often. Decide what your contract does when the answer is `false`. The safe pattern, used by `covered-vault`, is to **block new exposure but never block exits**.

## Call it from Rust

```rust
use soroban_sdk::{contractclient, contracttype, Address, Env};

#[contracttype]
#[derive(Clone, Copy)]
#[repr(u32)]
pub enum Tier { Transcribed = 1, IssuerSigned = 2, AuditorSigned = 3 }

#[contractclient(name = "CoverageLedgerClient")]
pub trait CoverageLedger {
    fn is_covered(env: Env, sac: Address, min_bps: u32, max_age: u64, min_tier: Tier) -> bool;
}

pub fn require_covered(env: &Env, ledger: &Address, asset: &Address) {
    let ok = CoverageLedgerClient::new(env, ledger)
        .is_covered(asset, &10_000, &604_800, &Tier::IssuerSigned);
    if !ok {
        panic!("asset not covered");
    }
}
```

## Need the number, not a yes/no?

`coverage(sac, min_tier)` returns the full reading (`bps`, `supply`, `reserves`, `tier`, timestamps), or `None`. Use it to scale a loan-to-value ratio, for example.

## Test against it locally

Register the real contracts in your tests from the wasm in [plimsoll-contracts releases](https://github.com/plimsoll-protocol/plimsoll-contracts/releases), or depend on the crates by git and use `env.register(CoverageLedger, ...)` as the `covered-vault` tests do.

## Cost

`is_covered` reads up to four storage entries: the supply snapshot and one report per tier at or above `min_tier`. In the testnet demo, a full vault deposit including the check cost 0.1468325 XLM.


---

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