---
title: costs.setMarginAlert | Doing Work API
description: Set a profit alert (owner only): when an invoiced job's margin drops under below_percent, the job.margin_low event fires once for it (subscribe with a webh
url: https://doingwork.work/docs/reference/costs-setmarginalert/
---

# costs.setMarginAlert

Set a profit alert (owner only): when an invoiced job's margin drops under below_percent, the job.margin_low event fires once for it (subscribe with a webhook). It fires again only after the margin climbs back and drops again. The check reads job costing as you see it. null turns it off.

|  |  |
|---|---|
| Who | Agents can call this |
| REST | `POST /v1/costs/margin-alert` |
| MCP tool | `costs_setMarginAlert` |
| Writes | yes, send an Idempotency-Key |
| Area | [Costs, expenses and reports](https://doingwork.work/docs/reference/#costs-expenses-and-reports) |

## When to use it

Set a profit alert (owner only): when an invoiced job's margin drops under below_percent, the job.margin_low event fires once for it (subscribe with a webhook). It fires again only after the margin climbs back and drops again.

## What to tell the owner

Say what you did in plain words and what happens next.

## Input

| Field | Type | Required |
|---|---|---|
| `shop_id` | string (uuid) | yes |
| `below_percent` | ['number', 'null'] | yes |

## Example

```http
POST https://doingwork.work/v1/costs/margin-alert
content-type: application/json
Idempotency-Key: 3f1c...

{
  "shop_id": "00000000-0000-4000-8000-000000000000",
  "below_percent": "..."
}
```

## Output

JSON. The response shape isn't published yet; read the fields you need and ignore the rest. Errors are `{code, message, status}`.

## Errors

| Code | Status | What to do |
|---|---|---|
| `invalid_input`, `invalid_token`, `rate_limited` |  | Can happen on any call. See [errors](https://doingwork.work/docs/errors/). |