Stop experiment

Stop an active experiment without a winner. A broadcast experiment stopped before launch is ignored at launch; after launch, recipients already queued are still sent and the untested remainder is never sent. A journey keeps splitting by the node weights but stops recording assignments.

Outcome

Before you start

Verify identity and pin the intended organization and environment before discovering the action.
Discover a granted Nurture workspace. The application permission is workspace:write; required workspace access is read_write. A permission alone does not supply a workspace grant.
Organization and workspace come from verified context. Select resourceType/resourceId separately from action input; body fields cannot grant a different organization or workspace. The first authorized product action can initialize an identity-only workspace mirror.
Obtain authorization for the documented effect or personal-data export before supplying CLI --confirm or MCP confirm:true.

Discover the target

topolo whoami --json
topolo actions get app_topolo_nurture.experiments.stop --detail --json
topolo resources topolo-nurture --json
topolo workspaces list topolo-nurture --json
topolo actions get app_topolo_nurture.experiments.list --detail --json

id: experiments record id in the selected workspace.

Request

POST /api/experiments/{id}/stop

Save action input as payload.json. The reviewed plan separates path identifiers, query fields and HTTP body. Set NURTURE_WORKSPACE_ID from granted resource discovery; it is separate from action input.

Inspect and test this action in the signed action console. A test response still requires the verification below.

Input fields

Field	Required	Type	Constraints
`id`	Required	string	experiments record id in the selected workspace. {"minLength":1,"maxLength":64}
`reason`	Optional	string	{"minLength":1,"maxLength":500}

Exact input schema:

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "id": {
      "type": "string",
      "minLength": 1,
      "maxLength": 64
    },
    "reason": {
      "type": "string",
      "minLength": 1,
      "maxLength": 500
    }
  },
  "required": [
    "id"
  ],
  "additionalProperties": false
}

Effects

Sets status stopped with stoppedBy, stoppedAt and the reason; results stay readable.

Interpret the response

The returned identifier path is $.experiment.id for experiment. Empty lists do not discover a target.

Call app_topolo_nurture.experiments.get and confirm status stopped.

Exact success schema:

{
  "type": "object",
  "required": [
    "experiment"
  ],
  "properties": {
    "experiment": {
      "type": "object",
      "required": [
        "id",
        "kind",
        "status",
        "arms",
        "controlArm",
        "goal"
      ],
      "properties": {
        "id": {
          "type": "string"
        },
        "name": {
          "type": "string"
        },
        "kind": {
          "type": "string",
          "enum": [
            "broadcast",
            "journey"
          ]
        },
        "broadcastId": {
          "type": [
            "string",
            "null"
          ]
        },
        "journeyId": {
          "type": [
            "string",
            "null"
          ]
        },
        "nodeId": {
          "type": [
            "string",
            "null"
          ]
        },
        "arms": {
          "type": "array",
          "items": {
            "type": "object",
            "required": [
              "key",
              "weight"
            ],
            "properties": {
              "key": {
                "type": "string"
              },
              "label": {
                "type": [
                  "string",
                  "null"
                ]
              },
              "weight": {
                "type": "integer"
              },
              "variant": {
                "type": "object"
              }
            }
          }
        },
        "controlArm": {
          "type": "string"
        },
        "holdoutPercent": {
          "type": "integer"
        },
        "testPercent": {
          "type": [
            "integer",
            "null"
          ]
        },
        "goal": {
          "type": "object",
          "required": [
            "kind",
            "windowHours"
          ],
          "properties": {
            "kind": {
              "type": "string",
              "enum": [
                "event",
                "click"
              ]
            },
            "eventType": {
              "type": "string"
            },
            "urlPrefix": {
              "type": [
                "string",
                "null"
              ]
            },
            "windowHours": {
              "type": "integer"
            }
          }
        },
        "minSamplePerArm": {
          "type": "integer"
        },
        "confidenceLevel": {
          "type": "number"
        },
        "status": {
          "type": "string",
          "enum": [
            "active",
            "stopped",
            "promoted"
          ]
        },
        "winnerArm": {
          "type": [
            "string",
            "null"
          ]
        },
        "promotedBy": {
          "type": [
            "string",
            "null"
          ]
        },
        "promotedAt": {
          "type": [
            "string",
            "null"
          ]
        },
        "promotionOverride": {
          "type": "boolean"
        },
        "overrideReason": {
          "type": [
            "string",
            "null"
          ]
        },
        "remainderRecipients": {
          "type": [
            "integer",
            "null"
          ]
        },
        "stoppedBy": {
          "type": [
            "string",
            "null"
          ]
        },
        "stoppedAt": {
          "type": [
            "string",
            "null"
          ]
        },
        "stopReason": {
          "type": [
            "string",
            "null"
          ]
        },
        "createdBy": {
          "type": "string"
        },
        "createdAt": {
          "type": "string"
        },
        "updatedAt": {
          "type": "string"
        }
      }
    }
  }
}

Worked examples

Actual dispatcher and migration-created SQLite or Worker handlers; identity/workspace and external service dependencies are simulated. Fixture identifiers and timestamps are synthetic. These responses establish no live authorization, paid generation, credential provisioning or message delivery. Replace synthetic identifiers using credential-scoped discovery. A local success is not evidence of a deployed effect, configured provider or delivered message.

Successful request

Actual dispatcher and migration-created SQLite; verified identity/workspace and external CRM, Engage, Notify, Consent, Nexus, Brand, Generator, Voice and delivery dependencies are simulated. No live authorization, paid generation or external delivery is established.

Input · payload.json:

{
  "id": "exp_41afd28d70724d678a329ee6bb478a54"
}

CLI:

topolo actions validate app_topolo_nurture.experiments.stop --data @payload.json --json
topolo actions plan app_topolo_nurture.experiments.stop --resource-type workspace --resource-id "$NURTURE_WORKSPACE_ID" --data @payload.json --json
topolo actions call app_topolo_nurture.experiments.stop --resource-type workspace --resource-id "$NURTURE_WORKSPACE_ID" --data @payload.json --confirm --json

MCP tool and arguments:

{
  "tool": "topolo_call_action",
  "arguments": {
    "actionId": "app_topolo_nurture.experiments.stop",
    "input": {
      "id": "exp_41afd28d70724d678a329ee6bb478a54"
    },
    "resourceType": "workspace",
    "resourceId": "<identifier returned by resource discovery>",
    "confirm": true
  }
}

Captured local response · HTTP 200:

{
  "experiment": {
    "id": "exp_41afd28d70724d678a329ee6bb478a54",
    "name": "Subject test",
    "kind": "broadcast",
    "broadcastId": "bc_982e00778f594bae9cc4b6483ff552a6",
    "journeyId": null,
    "nodeId": null,
    "arms": [
      {
        "key": "control",
        "label": null,
        "weight": 50,
        "variant": {}
      },
      {
        "key": "question",
        "label": "Question subject",
        "weight": 50,
        "variant": {
          "templateVersion": 1,
          "subject": "Ready?"
        }
      }
    ],
    "controlArm": "control",
    "holdoutPercent": 0,
    "testPercent": null,
    "goal": {
      "kind": "event",
      "eventType": "purchase",
      "windowHours": 72
    },
    "minSamplePerArm": 100,
    "confidenceLevel": 0.95,
    "status": "stopped",
    "winnerArm": null,
    "promotedBy": null,
    "promotedAt": null,
    "promotionOverride": false,
    "overrideReason": null,
    "remainderRecipients": null,
    "stoppedBy": "u1",
    "stoppedAt": "2026-10-01T09:00:00.000Z",
    "stopReason": null,
    "createdBy": "u1",
    "createdAt": "2026-10-04T00:32:35.384Z",
    "updatedAt": "2026-10-04T00:32:35.406Z"
  }
}

HTTP 200. Call app_topolo_nurture.experiments.get and confirm status stopped.

Another supported request

Input · payload.json:

{
  "id": "exp_91556290384e4d4fb088a3c851d808d9",
  "reason": "Wrong audience"
}

CLI:

topolo actions validate app_topolo_nurture.experiments.stop --data @payload.json --json
topolo actions plan app_topolo_nurture.experiments.stop --resource-type workspace --resource-id "$NURTURE_WORKSPACE_ID" --data @payload.json --json
topolo actions call app_topolo_nurture.experiments.stop --resource-type workspace --resource-id "$NURTURE_WORKSPACE_ID" --data @payload.json --confirm --json

MCP tool and arguments:

{
  "tool": "topolo_call_action",
  "arguments": {
    "actionId": "app_topolo_nurture.experiments.stop",
    "input": {
      "id": "exp_91556290384e4d4fb088a3c851d808d9",
      "reason": "Wrong audience"
    },
    "resourceType": "workspace",
    "resourceId": "<identifier returned by resource discovery>",
    "confirm": true
  }
}

Captured local response · HTTP 200:

{
  "experiment": {
    "id": "exp_91556290384e4d4fb088a3c851d808d9",
    "name": "T",
    "kind": "broadcast",
    "broadcastId": "bc_b4beb327e7334e16b6e953c97015aa74",
    "journeyId": null,
    "nodeId": null,
    "arms": [
      {
        "key": "control",
        "label": null,
        "weight": 50,
        "variant": {}
      },
      {
        "key": "question",
        "label": "Question subject",
        "weight": 50,
        "variant": {
          "templateVersion": 1,
          "subject": "Ready?"
        }
      }
    ],
    "controlArm": "control",
    "holdoutPercent": 0,
    "testPercent": null,
    "goal": {
      "kind": "event",
      "eventType": "purchase",
      "windowHours": 72
    },
    "minSamplePerArm": 100,
    "confidenceLevel": 0.95,
    "status": "stopped",
    "winnerArm": null,
    "promotedBy": null,
    "promotedAt": null,
    "promotionOverride": false,
    "overrideReason": null,
    "remainderRecipients": null,
    "stoppedBy": "u1",
    "stoppedAt": "2026-10-01T09:00:00.000Z",
    "stopReason": "Wrong audience",
    "createdBy": "u1",
    "createdAt": "2026-10-04T00:32:34.625Z",
    "updatedAt": "2026-10-04T00:32:34.627Z"
  }
}

HTTP 200. Call app_topolo_nurture.experiments.get and confirm status stopped.

Refused request · invalid_status

Input · payload.json:

{
  "id": "exp_e6a4ff5a74cb4129922a9c41aca79ca9"
}

CLI:

topolo actions validate app_topolo_nurture.experiments.stop --data @payload.json --json
topolo actions plan app_topolo_nurture.experiments.stop --resource-type workspace --resource-id "$NURTURE_WORKSPACE_ID" --data @payload.json --json

Captured local response · HTTP 409:

{
  "error": {
    "code": "invalid_status",
    "message": "The experiment is promoted.",
    "details": {
      "status": "promoted"
    }
  }
}

HTTP 409. Preserve the refusal details and do not claim success.

Refused request · not_found

Input · payload.json:

{
  "id": "exp_missing"
}

CLI:

topolo actions validate app_topolo_nurture.experiments.stop --data @payload.json --json
topolo actions plan app_topolo_nurture.experiments.stop --resource-type workspace --resource-id "$NURTURE_WORKSPACE_ID" --data @payload.json --json

Captured local response · HTTP 404:

{
  "error": {
    "code": "not_found",
    "message": "Experiment was not found in this workspace."
  }
}

HTTP 404. Preserve the refusal details and do not claim success.

Refused request · permission_denied

Input · payload.json:

{
  "id": "exp_613046a467e949b8a25148077998762f"
}

CLI:

topolo actions validate app_topolo_nurture.experiments.stop --data @payload.json --json
topolo actions plan app_topolo_nurture.experiments.stop --resource-type workspace --resource-id "$NURTURE_WORKSPACE_ID" --data @payload.json --json

Captured local response · HTTP 403:

{
  "error": {
    "code": "permission_denied",
    "message": "The credential lacks workspace:write.",
    "details": {
      "requiredPermission": "workspace:write"
    }
  }
}

HTTP 403. Preserve the refusal details and do not claim success.

Verify the result

Call app_topolo_nurture.experiments.get and confirm status stopped.

Errors and recovery

organization_required (HTTP 403): Select an organization available to the verified caller before choosing a Nurture workspace.
permission_denied (HTTP 403): Grant the credential the required Nurture workspace permission.
workspace_required (HTTP 409): Create a Nurture workspace, or pass the workspace resource context.
invalid_input (HTTP 422): Correct the fields named in error.details using inputSchema, then retry.
not_found (HTTP 404): List experiments to find a valid id in this workspace.
invalid_status (HTTP 409): Read the experiment with app_topolo_nurture.experiments.get; only an active experiment can be stopped, and a promoted one is final.

Auth or gateway failures may precede this handler. Preserve the exact response shape, error string/code, request id and credential context; no synthetic fixture establishes live credential access.

Recovery boundary

A stopped experiment cannot restart; create a new experiment instead. It can still be promoted.

Promote experiment winner: Make one arm the winner. It must be results.recommendedWinner (significant at 95%) unless override is true with an overrideReason; the override, reason and acting user are recorded. Broadcast with testPercent: the winner is queued for every remaining contact and the broadcast resumes sending (it must be sending or sent). Journey: the draft's split node is set to 100% winner (other arms weight 0, no holdout); publish the journey to make it live, as published versions never change. The experiment ends as promoted.
Create experiment: Set up an A/B test. kind broadcast: on a DRAFT broadcast, 2-5 arms { key, weight, templateVersion?, subject? } (an arm without overrides sends the broadcast as-is), optional holdoutPercent (0-50, receives nothing) and testPercent (1-99: only that share is tested at launch; the winner goes to the rest on promote). kind journey: journeyId and the nodeId of a split node in the draft; arms and holdout come from the node. Each contact's arm is hash(experiment id, contact id), recorded once. controlArm defaults to the first arm. Conversion, within goal.windowHours after exposure (send, split or withheld holdout): goal.kind event (default) = the lifecycle eventType (e.g. purchase); click = a tracked-link click on the experiment's own sends, only URLs starting with urlPrefix if set.

Evidence

Actual dispatcher and migration-created SQLite or Worker handlers; identity/workspace and external service dependencies are simulated. Fixture identifiers and timestamps are synthetic. These responses establish no live authorization, paid generation, credential provisioning or message delivery. Test scenario and capture digests are retained with each fixture.

Stop experiment

Outcome

Before you start

Discover the target

Request

Input fields

Effects

Interpret the response

Worked examples

Successful request

Another supported request

Refused request · invalid_status

Refused request · not_found

Refused request · permission_denied

Verify the result

Errors and recovery

Recovery boundary

Related actions

Evidence