> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vanna.finance/llms.txt
> Use this file to discover all available pages before exploring further.

# Tracking Tokens

> Single contract tracking Blend b-token positions and Aquarius/Soroswap LP token balances per margin account.

The `TrackingToken` contract is a single on-chain token registry that tracks synthetic position balances for each SmartAccount. Instead of querying external protocols (Blend, Aquarius, Soroswap) directly during health checks, the RiskEngine reads TrackingToken balances to determine a margin account's external positions.

**Testnet address:** `CA24GDWO63ZXNMW5FLWF2KMZ5DCF3DO7J3RYABFICDIDHH4A342RD2TR`

***

## Tracked Symbols

| Symbol        | Represents                       | Value in risk model                |
| ------------- | -------------------------------- | ---------------------------------- |
| `BLEND_XLM`   | XLM b-tokens held in Blend pool  | Valued via `b_rate × oracle price` |
| `BLEND_USDC`  | USDC b-tokens held in Blend pool | Valued via `b_rate × oracle price` |
| `AQ_XLM_USDC` | Aquarius XLM/USDC LP tokens      | `$0` (no oracle feed)              |
| `SS_XLM_USDC` | Soroswap XLM/USDC LP tokens      | `$0` (no oracle feed)              |

<Note>
  LP tokens (AQ\_XLM\_USDC, SS\_XLM\_USDC) are tracked to prevent double-counting but are valued at \$0 in health factor calculations. Only Blend b-tokens receive non-zero collateral valuation.
</Note>

***

## Mint / Burn Flow

TrackingTokens are minted and burned by the AccountManager based on the return value from `SmartAccount.execute()`:

```
SmartAccount.execute() → returns (success, token_delta)

if token_delta > 0:
    AccountManager → TrackingToken.mint(symbol, smart_account, token_delta)
if token_delta < 0:
    AccountManager → TrackingToken.burn(symbol, smart_account, -token_delta)
```

**Blend deposit:** mint `BLEND_XLM` equal to b-tokens received\
**Blend withdrawal:** burn `BLEND_XLM` equal to b-tokens returned\
**Aquarius add liquidity:** mint `AQ_XLM_USDC` equal to LP tokens received\
**Aquarius remove liquidity:** burn `AQ_XLM_USDC` equal to LP tokens burned

***

## Functions

### initialize

```rust theme={null}
fn initialize(
    env: Env,
    admin: Address,
    symbol: Symbol,
    decimals: u32,
    name: String,
) -> ()
```

One-time initialization per symbol. Sets the token info for a given tracking symbol.

***

### mint

```rust theme={null}
fn mint(
    env: Env,
    symbol: Symbol,
    to: Address,
    amount: i128,
) -> ()
```

Increases `to`'s balance for `symbol` by `amount`. Only callable by admin (AccountManager).

**Called when:** A SmartAccount deposits into Blend or adds liquidity to Aquarius/Soroswap.

***

### burn

```rust theme={null}
fn burn(
    env: Env,
    symbol: Symbol,
    from: Address,
    amount: i128,
) -> ()
```

Decreases `from`'s balance for `symbol` by `amount`. Only callable by admin (AccountManager).

**Called when:** A SmartAccount withdraws from Blend or removes liquidity from Aquarius/Soroswap.

***

### balance

```rust theme={null}
fn balance(env: Env, id: Address, symbol: Symbol) -> i128
```

Returns the tracking token balance for `id` and `symbol`. The primary read function used by RiskEngine during collateral valuation.

***

### total\_supply

```rust theme={null}
fn total_supply(env: Env, symbol: Symbol) -> i128
```

Returns the total tracking tokens minted across all accounts for `symbol`.

***

### admin

```rust theme={null}
fn admin(env: Env) -> Address
```

Returns the admin address (AccountManager).

***

### set\_admin

```rust theme={null}
fn set_admin(env: Env, new_admin: Address) -> ()
```

Changes the admin. Requires current admin auth.

***

## Storage Layout

| Key                        | Type                       | Description                     |
| -------------------------- | -------------------------- | ------------------------------- |
| `TokenInfo(Symbol)`        | `{decimals, name, symbol}` | Metadata per symbol             |
| `Admin`                    | `Address`                  | Admin (AccountManager)          |
| `TotalSupply(Symbol)`      | `i128`                     | Total minted per symbol         |
| `Balance(Address, Symbol)` | `i128`                     | Per-account, per-symbol balance |

***

## Reading TrackingToken Balances (TypeScript)

```typescript theme={null}
const TRACKING_TOKEN = 'CA24GDWO63ZXNMW5FLWF2KMZ5DCF3DO7J3RYABFICDIDHH4A342RD2TR';

// Check how many Blend XLM b-tokens a smart account has
const blendXlmBalance = await simulateCall(
  TRACKING_TOKEN,
  'balance',
  [smartAccountAddress, Symbol('BLEND_XLM')]
);

// Check Aquarius LP position
const aqLpBalance = await simulateCall(
  TRACKING_TOKEN,
  'balance',
  [smartAccountAddress, Symbol('AQ_XLM_USDC')]
);
```

***

## Related

* [SmartAccount](/developers/contracts/smart-account) — triggers mint/burn via `execute()` return value
* [AccountManager](/developers/contracts/account-manager) — calls `mint`/`burn` based on `token_delta`
* [Risk Engine](/developers/contracts/risk-engine) — reads balances for collateral valuation
* [Math Reference](/developers/math-reference#blend-b-token-valuation) — how Blend positions are priced