# update

URL: /business/nouns/demand-budget/update · Id: `verb:DemandBudget.update` · Call: `await $.DemandBudget.update({ … })` (SDK) or the `do` tool at `https://api.sb/mcp`. Inputs says what to pass, Outputs what returns, When it waits who approves.

> Changes the given properties of a Demand Budget.

Update changes the given properties of a [Demand Budget](/business/nouns/demand-budget). It is inherited: every [Noun](/business/nouns/noun) has `get`, `list`, `create`, `update` and `delete`.

## Inputs
| Input | Type | Required | Description |
| --- | --- | --- | --- |
| `id` | `string` | Yes | The id of the Demand Budget. |
| `amount` | `money` | No | The monthly spend it funds; zero is the default. |
| `tier` | `string` | No | One of `$0`, `$100`, `$1k`, `$10k` or `$100k`: the highest tier at or below the amount, whose Play mix it buys. |
| `target` | `string` | No | The Metric value the spend must reach, such as cost per first Order under $40. |
| `stopRule` | `string` | No | The reading that closes the budget, such as acquisition cost above margin for two weeks. |
| `until` | `date` | No | The last day the budget runs before its Decision is read. |

## Outputs
| Output | Type | Required | Description |
| --- | --- | --- | --- |
| `demandBudget` | [Demand Budget](/business/nouns/demand-budget) | Yes | The Demand Budget. |

## Effects
- Emits `DemandBudget.updated`.
- Two-way: `try`, `send`, `do`.

## Refuses when
| Check | Error | Fix | Then call |
| --- | --- | --- | --- |
| The key is valid, but its scopes do not allow this operation. | [`forbidden`](/code/api/errors/forbidden) | Use a key whose scopes cover the operation, or ask an owner of the namespace to grant them. | [DemandBudget.update](/business/nouns/demand-budget/update) |

## When it waits
| Gate | Default |
| --- | --- |
| Decision class | Low: two-way, nothing at stake |
| [Delay window](/systems/trust-and-governance/controls/one-way-windows) | None: it runs once review passes. |
| Limit | The call [Limit](/business/nouns/limit) of the [Permission](/business/nouns/permission) it runs under. |
| Over the Limit | It waits `pending` for an [Approval](/business/nouns/approval) from the [Founder](/agents/founding/founder). Approved, it runs; refused, it ends `refused` with [`limit-exceeded`](/code/api/errors/limit-exceeded); unanswered by its deadline, it ends `canceled`. |

## Example

**Ask**

```text
Change the latest demand budget.
```

**API**

```bash
curl -X PATCH https://api.sb/ledgerlark.com/demand-budgets/demand_budget_1 \
  -H "Authorization: Bearer $STARTUP_BUILDER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"amount":{"amount":400,"currency":"USD"}}'
```

```json
{
  "api": "https://api.sb/ledgerlark.com",
  "demandBudget": {
    "$id": "https://api.sb/ledgerlark.com/demand-budgets/demand_budget_1",
    "$type": "DemandBudget",
    "amount": {
      "amount": 400,
      "currency": "USD"
    },
    "tier": "$0",
    "target": "Example target",
    "stopRule": "Example stop rule"
  },
  "action": {
    "$id": "https://api.sb/ledgerlark.com/actions/action_1",
    "operation": "DemandBudget.update",
    "status": "done"
  },
  "links": {
    "self": "https://api.sb/ledgerlark.com/actions/action_1"
  }
}
```

**SDK**

```ts
import { $ } from 'startup-builder'

const demandBudget = await $.DemandBudget.update({ id: 'demand_budget_1', amount: { amount: 400, currency: 'USD' } })
```

**CLI**

```bash
npx startup-builder do DemandBudget.update --json '{"id":"demand_budget_1","amount":{"amount":400,"currency":"USD"}}'
```

**MCP**

```json
{
  "name": "do",
  "arguments": {
    "code": "return await $.DemandBudget.update({ id: 'demand_budget_1', amount: { amount: 400, currency: 'USD' } })"
  }
}
```