Create a cohort

{  "id": "an_cohort_q8w4e6r0t5y2u8k3v9m2x7c1",  "projectId": "proj_tz4a98xxat96iws9zmbrgj3a",  "name": "Power users",  "description": "Finished three workouts in the last 30 days.",  "kind": "dynamic",  "definition": {    "match": "all",    "conditions": [      {        "kind": "performed",        "event": "workout_completed",        "isNegated": false,        "count": {          "op": "gte",          "value": 3        },        "withinDays": 30,        "filters": []      }    ]  },  "memberCount": 128,  "createdAt": "2026-03-05T12:00:00.000Z",  "updatedAt": "2026-03-05T12:00:00.000Z"}

{  "error": {    "type": "invalid_request",    "code": "invalid_analytics_cohort",    "message": "Cohorts name each other in a circle: Power users names Lapsed, which names Power users."  }}

{  "error": {    "type": "unauthenticated",    "code": "invalid_api_key",    "message": "This secret key is not valid."  }}

{  "error": {    "type": "permission_denied",    "code": "permission_denied",    "message": "Insufficient permissions."  }}

{  "error": {    "type": "not_found",    "code": "project_not_found",    "message": "There is no project proj_tz4a98xxat96iws9zmbrgj3a, or this credential cannot use it.",    "param": "projectId"  }}

{  "error": {    "type": "internal",    "code": "internal_error",    "message": "Something went wrong on our side. Try again, and contact support with the Request-Id header if it keeps failing."  }}

{  "error": {    "type": "unavailable",    "code": "string",    "message": "string",    "param": "string"  }}