URL: /code/apps/analytics-and-experiments/conclude · Id: `page:/code/apps/analytics-and-experiments/conclude`

# Experiment.conclude

> Ends an Experiment with ship, kill or iterate, recorded as a Decision with its reason.

POST https://api.sb/{your-domain}/experiments/{experiment}/conclude

Ends an [Experiment](https://startupbuilder.dev/business/nouns/experiment) with ship, kill or iterate, recorded as a [Decision](https://startupbuilder.dev/business/nouns/decision) with its reason.

- **Action class:** None
- **Approval:** Runs on its own
- **Emits:** `Experiment.concluded`
- **Price:** Free

```text title="Run it · Ask"
End the subject-line test and keep the question subject.
```

```ts title="Run it · SDK"
import { $ } from 'startup-builder'

const result = await $.try.Experiment.conclude({ experiment: 'https://api.sb/leaseline.app/experiments/experiment_Wb6nC1vZ8q', decision: 'Keep the question subject: replies 6.1% against 3.4% over 400 sends.' })
```

```json title="Run it · Response"
{
  "api": "https://api.sb/leaseline.app",
  "experiment": {
    "$id": "https://api.sb/leaseline.app/experiments/experiment_Wb6nC1vZ8q",
    "$type": "Experiment",
    "status": "concluded"
  },
  "decision": {
    "$id": "https://api.sb/leaseline.app/decisions/decision_Qs3uB6jL1w",
    "$type": "Decision"
  },
  "action": {
    "operation": "Experiment.conclude",
    "mode": "try",
    "status": "done"
  }
}
```

Its Inputs, Outputs, Effects and guards quote [the hub’s `Experiment.conclude`](https://startupbuilder.dev/business/nouns/experiment/conclude); this page adds what each Venue honors, its limits and a worked call. It is one of the [Verbs](https://startupbuilder.dev/business/nouns/verb) of [Analytics and experiments](/code/apps/analytics-and-experiments#verbs).

## Inputs
| Name | Type | Default | Meaning |
| --- | --- | --- | --- |
| `experiment` | `Experiment` | Required | The running Experiment. |
| `decision` | `string` | Required | One of `ship`, `kill`, `iterate`. |

## Outputs
| Field | Type | What `null` means |
| --- | --- | --- |
| `decision` | `Decision` | Never null: the recorded Decision. |
| `experiment` | `Experiment` | Never null: the Experiment, now concluded. |

## Effects
**Action class**

None: no approval rule names it, so it runs within its seat’s Permissions and Limits

**Modes**

- `try`: Runs every check and returns the record as it would be; nothing is stored.
- `send`: Returns a pending Action at once; `Experiment.concluded` fires when it is done.
- `do`: Waits for the Action to finish and returns the record.

**Idempotency**

Only with a key: the same `Idempotency-Key` and input return the first Action, and the same key with other input returns `409`.

**Saved or shared**

Moves each tested Hypothesis to supported or refuted. Ships the winning variant when the decision is `ship`.

**Emits**

`Experiment.concluded` with `{ experiment }`

**Performed by**

Whichever seat calls it

**Price**

Free on your own account: the platform charges nothing for the call.

## On each Venue
It acts on your own records and reaches no Venue, so every account answers the same way.

## What try does
Runs every check the call meets and returns the record as it would be; nothing is stored, sent or posted.

## Refuses when
The hub sets no guard of its own on this call: it refuses only on the shared checks every write meets (a missing record, a Permission the seat lacks).

## When it waits
Returns in one response; nothing waits.

## Example
In `send` mode the call returns its pending Action at once, and `Experiment.concluded` delivers the result.

**Ask**

```text
End the subject-line test and keep the question subject.
```

**API**

```bash
curl -X POST "https://api.sb/leaseline.app/experiments/experiment_Wb6nC1vZ8q/conclude?mode=send" \
  -H "Authorization: Bearer $SB_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
  "decision": "Keep the question subject: replies 6.1% against 3.4% over 400 sends."
}'
```

**CLI**

```bash
npx startup-builder do Experiment.conclude --send --data '{
  "decision": "Keep the question subject: replies 6.1% against 3.4% over 400 sends."
}'
```

`--send` returns the pending Action at once.

**MCP**

```json
{
  "name": "do",
  "arguments": {
    "mode": "send",
    "code": "return await $.Experiment.conclude({ decision: 'Keep the question subject: replies 6.1% against 3.4% over 400 sends.' })"
  }
}
```

**SDK**

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

const result = await $.send.Experiment.conclude({
  experiment: 'https://api.sb/leaseline.app/experiments/experiment_Wb6nC1vZ8q',
  decision: 'Keep the question subject: replies 6.1% against 3.4% over 400 sends.',
})
```


```json title="Response, in send mode"
{
  "mode": "send",
  "action": {
    "$id": "https://api.sb/leaseline.app/actions/action_Sd3kQ9vT2w",
    "operation": "Experiment.conclude",
    "status": "pending",
    "reason": "running"
  }
}
```

To retry, send the same `Idempotency-Key`: the retry returns the first answer for $0. A new key reads again.

## Used by
- **Agent tasks:** [Message test](/capabilities/run-ads/message-test)

## Related
[`Metric.query`](/code/apps/analytics-and-experiments/query) · [`Metric.watch`](/code/apps/analytics-and-experiments/watch) · [`Experiment.start`](/code/apps/analytics-and-experiments/start) · [`Dashboard.ask`](/code/apps/analytics-and-experiments/ask) · [`Metric.define`](/code/apps/analytics-and-experiments/define) · [`Event.capture`](/code/apps/analytics-and-experiments/capture) · [`Hypothesis.test`](/code/apps/analytics-and-experiments/test) · [`Dashboard.schedule`](/code/apps/analytics-and-experiments/schedule)