# exercise

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

> Exercise buys the Shares an option or warrant covers at its strike price, up to what has vested.

Exercise buys the [Shares](/business/nouns/share) an option or warrant covers at its strike price, up to what has vested.

## Inputs
| Input | Type | Required | Description |
| --- | --- | --- | --- |
| `instrument` | [Instrument](/business/nouns/instrument) | Yes | The option or warrant. |
| `quantity` | `integer` | Yes | How many Shares to buy. |

## Outputs
| Output | Type | Required | Description |
| --- | --- | --- | --- |
| `share` | [Share](/business/nouns/share) | Yes | The Shares bought. |
| `instrument` | [Instrument](/business/nouns/instrument) | Yes | The Instrument, now exercised. |

## Effects
- Emits [`Instrument.exercised`](/business/events/Instrument.exercised).
- Performed by the [Legal Lead](/agents/legal/legal-lead).
- One-way (money): it waits out its delay window, and runs in the `send` and `do` modes.

## 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. | [Instrument.exercise](/business/nouns/instrument/exercise) |

## When it waits
| Gate | Default |
| --- | --- |
| Decision class | Medium: one-way, bounded (money) |
| [Delay window](/systems/trust-and-governance/controls/one-way-windows) | 1 business hour, in which a watcher can pause, redirect or cancel it; then it runs. |
| Limit | The spend [Limit](/business/nouns/limit) of the [Permission](/business/nouns/permission) or [Mandate](/business/nouns/mandate) 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
Exercise the latest instrument.
```

**API**

```bash
curl -X POST https://api.sb/patentpad.com/instruments/instrument_1/exercise \
  -H "Authorization: Bearer $STARTUP_BUILDER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"quantity":1}'
```

```json
{
  "api": "https://api.sb/patentpad.com",
  "share": {
    "$id": "https://api.sb/patentpad.com/shares/share_1",
    "$type": "Share",
    "class": "common",
    "quantity": 1
  },
  "instrument": {
    "$id": "https://api.sb/patentpad.com/instruments/instrument_1",
    "$type": "Instrument",
    "kind": "safe",
    "status": "outstanding"
  },
  "action": {
    "$id": "https://api.sb/patentpad.com/actions/action_1",
    "operation": "Instrument.exercise",
    "status": "done"
  },
  "links": {
    "self": "https://api.sb/patentpad.com/actions/action_1"
  }
}
```

**SDK**

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

const { share, instrument } = await $.Instrument.exercise({ instrument: 'instrument_1', quantity: 1 })
```

**CLI**

```bash
npx startup-builder do Instrument.exercise --json '{"instrument":"instrument_1","quantity":1}'
```

**MCP**

```json
{
  "name": "do",
  "arguments": {
    "code": "return await $.Instrument.exercise({ instrument: 'instrument_1', quantity: 1 })"
  }
}
```