Sable Sentinel

The Sentinel vault is the simplest and safest BTC yield strategy on Sable. It supplies WBTC directly to the Vesu PRIME lending pool, earning base lending APY plus BTCFi Season STRK rewards.

Risk Level: 1 (Low)
Strategy: Pure lending with no leverage, no debt, no swaps

Strategy Overview

Sentinel implements a single-step strategy:

WBTC Deposit → Vesu PRIME Pool → Lending Yield + STRK Rewards

Yield Sources

Source	Type	Description
Vesu Lending APY	Base yield	Interest from WBTC borrowers on Vesu PRIME
BTCFi STRK Rewards	Incentive	100M STRK distribution for BTC strategies

Risk Profile

No leverage: No borrowed positions or liquidation risk
No external dependencies: Single protocol integration (Vesu)
No price risk: No exposure to volatile assets like ETH or USDC
Smart contract risk only: Limited to Vesu PRIME pool audits

Contract Architecture

File: sentinel.cairo (~500 LOC)
Deployed: 0x04ec7fdb1679450fb88eae9facc439a46be4ddeba628211e269a7467f6e0971b

Core Components

ERC-4626 Vault
Vesu Integration
Auto-Deploy

Sentinel implements the ERC-4626 tokenized vault standard:

Share Token: yvBTC-SENT (8 decimals)
Asset: WBTC (8 decimals)
Share Price: Increases as Vesu lending yield accrues

fn total_assets(self: @ContractState) -> u256 {
    self.total_assets_managed.read()
}

fn convert_to_shares(self: @ContractState, assets: u256) -> u256 {
    let supply = self.total_supply.read();
    let total = self.total_assets_managed.read();
    if supply == 0 || total == 0 { assets } else { (assets * supply) / total }
}

Sentinel interacts with a single Vesu pool (PRIME) for all operations:

fn deploy_to_vesu(ref self: ContractState, amount: u256) {
    self._assert_owner();
    let params = ModifyPositionParams {
        collateral_asset: wbtc_addr,
        debt_asset: self.debt_asset.read(),
        user: this,
        collateral: Amount {
            denomination: AmountDenomination::Assets,
            value: i257 { abs: amount, is_negative: false },
        },
        debt: Amount {
            denomination: AmountDenomination::Assets,
            value: i257 { abs: 0, is_negative: false },
        },
    };
    vesu.modify_position(params);
}

New deposits are automatically deployed to Vesu if they exceed the dust threshold:

fn _deploy_to_strategy(ref self: ContractState, amount: u256) {
    // Query Vesu dust threshold: min = floor * scale / price
    let config = vesu.asset_config(wbtc_addr);
    let asset_price = vesu.price(wbtc_addr);
    if asset_price.value > 0 && config.floor > 0 {
        let min_amount = (config.floor * config.scale) / asset_price.value + 1;
        if amount < min_amount { return; }
    }

    wbtc.approve(pool_addr, amount);
    vesu.modify_position(params);
}

Minimum Deposit: Dynamically calculated from Vesu’s $10 floor requirement

Key Functions

User Functions

deposit

function

Deposit WBTC and receive yvBTC-SENT sharesParameters:

assets (u256): Amount of WBTC to deposit (8 decimals)
receiver (ContractAddress): Address to receive vault shares

Returns: u256 — Number of shares minted

fn deposit(ref self: ContractState, assets: u256, receiver: ContractAddress) -> u256

withdraw

function

Burn shares and withdraw WBTCParameters:

assets (u256): Amount of WBTC to withdraw
receiver (ContractAddress): Address to receive WBTC
owner (ContractAddress): Share owner (must approve if caller ≠ owner)

Returns: u256 — Number of shares burned

fn withdraw(ref self: ContractState, assets: u256, receiver: ContractAddress, owner: ContractAddress) -> u256

Withdrawal automatically unwinds Vesu positions if idle WBTC is insufficient.

total_assets

view

Get total WBTC managed by the vault (idle + deployed)

fn total_assets(self: @ContractState) -> u256

Value from sentinel.cairo:183

Curator Functions

These functions are owner-only and manage the vault’s Vesu strategy.

deploy_to_vesu

function

Deploy idle WBTC to Vesu PRIME pool as collateralParameters:

amount (u256): WBTC amount to deploy

fn deploy_to_vesu(ref self: ContractState, amount: u256)

Implementation at sentinel.cairo:351

withdraw_from_vesu

function

Withdraw WBTC collateral from Vesu back to vaultParameters:

amount (u256): WBTC amount to withdraw

fn withdraw_from_vesu(ref self: ContractState, amount: u256)

Implementation at sentinel.cairo:380

harvest

function

Refresh total_assets from Vesu on-chain position

fn harvest(ref self: ContractState)

Reads Vesu position value and updates total_assets_managed, increasing share price. Implementation at sentinel.cairo:409

Integration with Vesu

Vesu PRIME Pool

Pool ID: 0x0451fe483d5921a2919ddd81d0de6696669bccdacd859f72a4fba7656b97c3b5 Sentinel supplies WBTC to the Vesu PRIME lending pool and earns:

Base APY: Interest from borrowers (variable rate)
BTCFi Rewards: STRK token incentives from StarkNet’s 100M STRK BTCFi Season program

Position Accounting

fn _refresh_total_assets(ref self: ContractState) {
    let vesu = IVesuPoolDispatcher { contract_address: pool_addr };
    let (_position, collateral_value, _debt_value) = vesu.position(wbtc_addr, debt_asset, this);
    let idle = wbtc.balance_of(this);
    self.total_assets_managed.write(collateral_value + idle);
}

From sentinel.cairo:483

Example Usage

Depositing WBTC

import { Contract, Account } from 'starknet'

const sentinelVault = new Contract(sentinelABI, sentinelAddress, account)
const wbtc = new Contract(erc20ABI, wbtcAddress, account)

// 1. Approve Sentinel vault to spend WBTC
const amount = 100_000_000n // 1 WBTC (8 decimals)
await wbtc.approve(sentinelAddress, amount)

// 2. Deposit WBTC and receive yvBTC-SENT shares
const { transaction_hash } = await sentinelVault.deposit(amount, account.address)

Withdrawing WBTC

// Get current share balance
const shares = await sentinelVault.balance_of(account.address)

// Convert shares to WBTC amount
const wbtcOut = await sentinelVault.convert_to_assets(shares)

// Withdraw all WBTC (burns all shares)
await sentinelVault.redeem(shares, account.address, account.address)

Checking Vault Stats

// Total WBTC managed (idle + deployed)
const totalAssets = await sentinelVault.total_assets()

// Current share price (WBTC per share)
const totalSupply = await sentinelVault.total_supply()
const sharePrice = totalAssets / totalSupply

// Strategy info: (collateral, debt, loops, paused)
const [collateral, debt, loops, paused] = await sentinelVault.get_strategy_info()

Security Considerations

Smart Contract Risk: Sentinel’s safety depends on Vesu PRIME pool security

Overview

Vault Contracts

Privacy Contracts

Other Contracts

Sentinel Vault

Sable Sentinel

Strategy Overview

Yield Sources

Risk Profile

Contract Architecture

Core Components

Key Functions

User Functions

Curator Functions

Integration with Vesu

Vesu PRIME Pool

Position Accounting

Example Usage

Depositing WBTC

Withdrawing WBTC

Checking Vault Stats

Security Considerations

Risk Mitigation

Audits

Additional Resources

Build docs developers (and LLMs) love

Overview

Vault Contracts

Privacy Contracts

Other Contracts

​Sable Sentinel

​Strategy Overview

​Yield Sources

​Risk Profile

​Contract Architecture

​Core Components

​Key Functions

​User Functions

​Curator Functions

​Integration with Vesu

​Vesu PRIME Pool

​Position Accounting

​Example Usage

​Depositing WBTC

​Withdrawing WBTC

​Checking Vault Stats

​Security Considerations

​Risk Mitigation

​Audits

​Additional Resources

Build docs developers (and LLMs) love

Sable Sentinel

Strategy Overview

Yield Sources

Risk Profile

Contract Architecture

Core Components

Key Functions

User Functions

Curator Functions

Integration with Vesu

Vesu PRIME Pool

Position Accounting

Example Usage

Depositing WBTC

Withdrawing WBTC

Checking Vault Stats

Security Considerations

Risk Mitigation

Audits

Additional Resources