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

# Stop Experiment

> End an active experiment and return traffic to baseline.

### Overview

Completes an active experiment with `completed_reason: "manual"`. Eligible calls immediately return to the baseline pin, and the final `variant_calls_routed` count is frozen on the record. Completion is permanent: a stopped experiment cannot be resumed, so use [Create Experiment](https://docs.bland.ai/api-v2/post/agents-id-experiments.md) to test again. Returns `409 CONFLICT` if the experiment is already completed for any reason.

Requires an admin, owner, operator, or prompter role. This endpoint takes no body.

### Headers

**authorization** `string` *required*

Your API key for authentication.

### Path Parameters

**agent\_id** `string` *required*

The agent's unique identifier.

**experiment\_id** `string` *required*

The experiment's unique identifier. Must be a valid UUID; returns `400 BAD_REQUEST` otherwise.

### Response

**data.experiment** `object`

The stopped experiment.

**experiment object**

**id** `string`

Unique identifier for the experiment.

**agent\_id** `string`

The agent the experiment belonged to.

**status** `string`

Always `completed` on success.

**completed\_reason** `string`

Always `manual` on success.

**baseline\_env** `string`

The control environment: `production` or `staging`.

**baseline\_current\_version\_id** `string | null`

The version currently pinned to `baseline_env`, which all eligible traffic now runs.

**variant\_version\_id** `string`

The version that was under test.

**traffic\_percentage** `integer`

The share of eligible calls the variant was receiving when stopped.

**run\_hours** `object | null`

The weekly schedule that was in effect, or `null`.

**starts\_at** `string | null`

The configured start, or `null`.

**ends\_at** `string | null`

The configured end date, or `null`.

**variant\_call\_quota** `integer | null`

The configured cap, or `null`.

**variant\_calls\_routed** `integer`

Final count of connected calls routed to the variant.

**created\_by** `string | null`

ID of the user who created the experiment, or `null` when created with an org-level key.

**created\_at** `string`

ISO 8601 timestamp of creation.

**completed\_at** `string`

ISO 8601 timestamp of this stop.

**errors** `null | array`

`null` on success, or a list of error objects if the request failed.

```json Response theme={null}
{
  "data": {
    "experiment": {
      "id": "339da41c-429f-4a5b-81c5-5f33fe01a266",
      "agent_id": "b8c322a1-9498-4a20-abd0-78ab3957b7d8",
      "status": "completed",
      "completed_reason": "manual",
      "baseline_env": "staging",
      "baseline_current_version_id": "4f8eb28b-8d56-44bb-9297-afe154f5acea",
      "variant_version_id": "2adb110d-e30d-49db-9e68-1d0904e462e3",
      "traffic_percentage": 40,
      "run_hours": null,
      "starts_at": null,
      "ends_at": null,
      "variant_call_quota": null,
      "variant_calls_routed": 96,
      "created_by": "c52e0087-b404-46af-aa5f-073edb5a3913",
      "created_at": "2026-09-09T09:05:44.310Z",
      "completed_at": "2026-09-10T21:37:12.654Z"
    }
  },
  "errors": null
}
```

```json Already Completed theme={null}
{
  "data": null,
  "errors": [
    {
      "error": "CONFLICT",
      "message": "The experiment is already completed"
    }
  ]
}
```

```json Not Found theme={null}
{
  "data": null,
  "errors": [
    {
      "error": "NOT_FOUND",
      "message": "Experiment not found"
    }
  ]
}
```

***

Docs for agents: [llms.txt](https://docs.bland.ai/llms.txt)


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