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

# Plan Add Backing

> Create a plan to add collateral to a Morpho position

# Plan Add Backing

Creates a plan to add backing (collateral) to an existing Morpho leveraged position. This improves the position's health factor without changing leverage. Returns a plan ID and an EIP-712 digest that must be signed to authorize execution.

## Request

```
POST /accounts/:account_id/plan/add-backing
```

### Path parameters

| Parameter    | Type   | Description        |
| ------------ | ------ | ------------------ |
| `account_id` | string | The sub-account ID |

### Body parameters

| Parameter        | Type    | Required | Description                                          |
| ---------------- | ------- | -------- | ---------------------------------------------------- |
| `exposure_asset` | string  | Yes      | The position's exposure asset (e.g., `"WETH"`)       |
| `backing_asset`  | string  | Yes      | The backing/collateral asset (e.g., `"USDC"`)        |
| `market_id`      | string  | Yes      | Morpho market ID (0x-prefixed 32-byte hex)           |
| `amount`         | string  | Yes      | Amount of backing asset to add in its smallest unit  |
| `is_short`       | boolean | Yes      | `true` if this is a short position, `false` for long |
| `network`        | string  | Yes      | Network name (e.g., `"base"`, `"mainnet"`)           |

## Examples

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://prime-api.legend.xyz/accounts/acc_2o0yiljtp378/plan/add-backing \
    -H "Authorization: Bearer $LEGEND_QUERY_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "exposure_asset": "WETH",
      "backing_asset": "USDC",
      "market_id": "0xb323495f7e4148be5643a4ea4a8221eef163e4bccfdedc2a6f4696baacbc86cc",
      "amount": "1000000000",
      "is_short": false,
      "network": "base"
    }'
  ```

  ```typescript TypeScript theme={null}
  const plan = await client.plan.addBacking("acc_2o0yiljtp378", {
    exposureAsset: "WETH",
    backingAsset: "USDC",
    marketId: "0xb323495f7e4148be5643a4ea4a8221eef163e4bccfdedc2a6f4696baacbc86cc",
    amount: "1000000000",
    isShort: false,
    network: "base",
  });
  ```

  ```python Python theme={null}
  plan = await client.plan.add_backing(
      "acc_2o0yiljtp378",
      exposure_asset="WETH",
      backing_asset="USDC",
      market_id="0xb323495f7e4148be5643a4ea4a8221eef163e4bccfdedc2a6f4696baacbc86cc",
      amount="1000000000",
      is_short=False,
      network="base",
  )
  ```

  ```rust Rust theme={null}
  use legend_client::AddBackingParams;

  let plan = client.plan.add_backing("acc_2o0yiljtp378", &AddBackingParams {
      exposure_asset: "WETH".into(),
      backing_asset: "USDC".into(),
      market_id: "0xb323495f7e4148be5643a4ea4a8221eef163e4bccfdedc2a6f4696baacbc86cc".into(),
      amount: "1000000000".into(),
      is_short: false,
      network: "base".into(),
  }).await?;
  ```
</CodeGroup>

```json Response (201 Created) theme={null}
{
  "plan_id": "pln_71mcui082png",
  "details": {
    "quark_operation_actions": [...],
    "eip712_data": {
      "digest": "0x8a3f...b7c2",
      "domain_separator": "0x...",
      "hash_struct": "0x..."
    }
  },
  "expires_at": "2025-06-15T10:32:00Z"
}
```

### Response fields

| Field                        | Type   | Description                                                 |
| ---------------------------- | ------ | ----------------------------------------------------------- |
| `plan_id`                    | string | Unique identifier for this plan (`pln_` prefix)             |
| `details`                    | object | Transaction details including EIP-712 signing data          |
| `details.eip712_data.digest` | string | The hash to sign with the account's signer key              |
| `expires_at`                 | string | ISO 8601 timestamp — plan must be executed before this time |

## Errors

| Status | Code             | Description                                      |
| ------ | ---------------- | ------------------------------------------------ |
| 400    | `invalid_params` | Missing required parameters or invalid market ID |
| 400    | `plan_failed`    | Could not generate a valid plan                  |
| 400    | `no_wallet`      | Account has no wallets                           |
| 408    | `timeout`        | Folio computation timed out                      |

## Notes

* Plans expire after 2 minutes. Sign and execute via [Execute Plan](/api-reference/plan-execute) before expiry.
* The `market_id` must match the Morpho market of the existing position.
* Use [Plan Withdraw Backing](/api-reference/plan-withdraw-backing) to remove collateral from a position.