> For the complete documentation index, see [llms.txt](https://developers.term.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.term.finance/periphery-contracts/curated-vaults/core-functionality/term-protocol-operations/protocol-interactions.md).

# Protocol Interactions

### Overview

In addition to the standard ERC-4626 methods implemented via Yearn V3 base operations, Term's custom strategy extends the **BaseStrategy** to include two key Term-specific functionalities:

1. **Auction Participation**: Enables the submission of offers into Term auctions, callable only by a designated manager.
2. **Direct Repo Token Liquidity**: Allows public users to sell repoTokens into the vault.

### **Validation and Risk Management (Shared Across Methods)**

| **Validation Criteria**                                    | **Description**                                                                             |
| ---------------------------------------------------------- | ------------------------------------------------------------------------------------------- |
| <mark style="color:blue;">**RepoToken Eligibility**</mark> |                                                                                             |
| Not Blacklisted                                            | `repoTokenBlacklist[repoToken] == false`                                                    |
| Recognized in TermController                               | `_isTermDeployed(repoToken) == true`                                                        |
| Not Matured                                                | `redemptionTimestamp > block.timestamp`                                                     |
| Collateral Requirements                                    | `maintenanceCollateralRatios >= minCollateralRatio`                                         |
| <mark style="color:blue;">**Portfolio Constraints**</mark> | *(from StrategyState struct)*                                                               |
| Maximum Maturity                                           | Ensures the weighted average maturity of the portfolio is below `timeToMaturityThreshold`.  |
| Reserve Ratio                                              | Maintains at least `requiredReserveRatio` for liquidity.                                    |
| Exposure Limits                                            | Verifies that exposure to a single repoToken does not exceed `repoTokenConcentrationLimit`. |

**Additiona Safeguards**:

* Reentrancy guards prevent recursive exploits in state-modifying functions.
* Pausable operations allow emergency suspension.
* Role-based access control ensures restricted access where required.
* Configurable blacklist functionality excludes prohibited repoTokens.

### Auction Participation

Callable by `MANAGER` only. Allows `MANAGER` to submit an offer into an eligible Term auctions, provided the offer satisfies all portfolio risk constraints.

```solidity
function submitAuctionOffer(
    ITermAuction termAuction,
    address repoToken,
    bytes32 idHash,
    bytes32 offerPriceHash,
    uint256 purchaseTokenAmount
) external returns (bytes32[] memory)
```

```solidity
function deleteAuctionOffers(address, bytes32[]) external
```

**Features**:

* Submits an offer into a Term auction after passing validation and portfolio risk checks.
* Restricted to the `MANAGER` role for controlled access.

### Direct Repo Token Liquidity

The `sellRepoToken` method provides a public interface for users to sell repoTokens into the vault.

```solidity
function sellRepoToken(
    address repoToken,
    uint256 repoTokenAmount
) external
```

**Features**:

* Facilitates liquidity by allowing users to sell repoTokens to the vault.
* Applies the `discountRateMarkup` to determine the repoToken's value.