> ## Documentation Index > Fetch the complete documentation index at: https://docs.continuouslabs.ai/llms.txt > Use this file to discover all available pages before exploring further. # Get World Change > Returns a membership change and its outcome. ## OpenAPI ````yaml /openapi/simulation.yaml get /v1/worlds/{id}/changes/{change_id} openapi: 3.1.0 info: description: >- Build Simulators from OpenAPI, WSDL or GraphQL documents, create Simulations from them, and build Worlds that run Simulations together. Authenticate every request with an API key sent as a Bearer token. title: Continuous Simulation API version: v1 servers: - description: Continuous production API. url: https://api.continuouslabs.ai security: [] tags: - description: >- Build Simulators from OpenAPI, WSDL or GraphQL documents, check or cancel a build, clone Simulators into other workspaces, and delete Simulators. name: simulators x-group: Simulators - description: >- Create Simulations from ready Simulators, then fork, stop, start, and delete them. name: simulations x-group: Simulations - description: >- Build Worlds from one or more Simulators and start or stop their Simulations together. name: worlds x-group: Worlds - description: >- Store connections to real systems: a base URL, the header that carries the credential, and its value. The API never returns a value. name: credentials x-group: Credentials paths: /v1/worlds/{id}/changes/{change_id}: get: tags: - worlds summary: Get World Change description: Returns a membership change and its outcome. operationId: get-world-change parameters: - description: World ID. in: path name: id required: true schema: pattern: ^wld_[0-9A-HJKMNP-TV-Z]{26}$ type: string - description: Membership change ID. in: path name: change_id required: true schema: pattern: ^wch_[0-9A-HJKMNP-TV-Z]{26}$ type: string responses: '200': content: application/json: schema: $ref: '#/components/schemas/WorldChange' description: OK '401': $ref: '#/components/responses/Unauthorized' '403': content: application/problem+json: examples: auth_forbidden_world: $ref: '#/components/examples/auth_forbidden_world' schema: $ref: '#/components/schemas/Error' description: Forbidden '404': content: application/problem+json: examples: world_change_not_found: $ref: '#/components/examples/world_change_not_found' world_not_found: $ref: '#/components/examples/world_not_found' schema: $ref: '#/components/schemas/Error' description: Not Found '500': $ref: '#/components/responses/InternalServerError' '503': content: application/problem+json: examples: auth_provider_unavailable: $ref: '#/components/examples/auth_provider_unavailable' internal_unavailable: $ref: '#/components/examples/internal_unavailable' schema: $ref: '#/components/schemas/Error' description: Service Unavailable security: - apiKeyAuth: [] components: schemas: WorldChange: additionalProperties: false examples: - completed_at: null created_at: '2026-01-15T12:00:00Z' delete: false error: null id: wch_01J8Z5X4K7M2N9P0Q1R2S3T4VB kind: add simulation: id: sim_01J8Z5X4K7M2N9P0Q1R2S3T4V6 simulator_id: smr_01J8Z5X4K7M2N9P0Q1R2S3T4V5 status: applying world_id: wld_01J8Z5X4K7M2N9P0Q1R2S3T4V7 properties: completed_at: description: Time the change completed or failed, or null while it runs. format: date-time type: - string - 'null' created_at: description: Change creation time. format: date-time type: string delete: description: Whether a removed member is deleted rather than detached. type: boolean error: $ref: '#/components/schemas/ResourceError' description: Safe failure information, or null when no failure is recorded. id: description: Membership change ID. pattern: ^wch_[0-9A-HJKMNP-TV-Z]{26}$ type: string kind: description: add adds a member; remove detaches or deletes one. enum: - add - remove type: string simulation: $ref: '#/components/schemas/WorldSimulation' description: The member this change adds or removes. status: description: Durable change state. Poll while pending, building, or applying. enum: - pending - building - applying - completed - failed type: string world_id: description: World ID. pattern: ^wld_[0-9A-HJKMNP-TV-Z]{26}$ type: string required: - id - world_id - kind - status - simulation - delete - error - created_at - completed_at type: object Error: additionalProperties: false properties: code: description: Stable machine-readable error code. minLength: 1 type: string detail: description: Safe human-readable error detail. minLength: 1 type: string validation: $ref: '#/components/schemas/SpecificationValidation' description: >- Safe specification diagnostics for a rejected build request, when available. required: - validation - code - detail type: object ResourceError: additionalProperties: false properties: code: description: Stable machine-readable error code. type: string detail: description: Safe human-readable error detail. type: string required: - code - detail type: - object - 'null' WorldSimulation: additionalProperties: false properties: id: description: ID of the created Simulation. pattern: ^sim_[0-9A-HJKMNP-TV-Z]{26}$ type: string simulator_id: description: ID of the Simulator that this Simulation runs. pattern: ^smr_[0-9A-HJKMNP-TV-Z]{26}$ type: string required: - id - simulator_id type: object SpecificationValidation: additionalProperties: false properties: issues: description: Specification validation problems. At most 20 are returned. items: $ref: '#/components/schemas/SpecificationIssue' maxItems: 20 type: array required: - issues type: - object - 'null' SpecificationIssue: additionalProperties: false properties: code: description: Stable validation rule code. type: string kind: description: >- Whether the input is invalid, unsupported, incomplete, or has no specific diagnosis. enum: - invalid - unsupported - incomplete - unknown type: string location: description: Readable endpoint or field affected by this issue. maxLength: 512 type: string message: description: What needs attention at this location. type: string operation: description: >- Affected operation ID or method and path, when available. Empty for document-level issues. maxLength: 243 type: string suggestion: description: How to correct or address the problem. type: string required: - code - operation - location - kind - message - suggestion type: object responses: Unauthorized: content: application/problem+json: examples: auth_invalid: $ref: '#/components/examples/auth_invalid' auth_missing: $ref: '#/components/examples/auth_missing' schema: $ref: '#/components/schemas/Error' description: Unauthorized InternalServerError: content: application/problem+json: examples: internal: $ref: '#/components/examples/internal' schema: $ref: '#/components/schemas/Error' description: Internal Server Error examples: auth_forbidden_world: value: code: auth_forbidden detail: >- The World with ID "wld_01J8Z5X4K7M2N9P0Q1R2S3T4V7" belongs to another workspace. validation: null world_change_not_found: value: code: world_change_not_found detail: The World change was not found. validation: null world_not_found: value: code: world_not_found detail: No World was found with ID "wld_01J8Z5X4K7M2N9P0Q1R2S3T4V7". validation: null auth_provider_unavailable: value: code: auth_provider_unavailable detail: >- The authentication provider is unavailable. Retry the request after a short delay. validation: null internal_unavailable: value: code: internal_unavailable detail: >- The service is temporarily unavailable. Retry the request after a short delay. validation: null auth_invalid: value: code: auth_invalid detail: The authentication credential is invalid. validation: null auth_missing: value: code: auth_invalid detail: Authentication credentials are required. validation: null internal: value: code: internal detail: The server encountered an unexpected error. validation: null securitySchemes: apiKeyAuth: bearerFormat: Continuous API key description: >- Use a Continuous API key. Send it in the Authorization header as a Bearer token. scheme: bearer type: http ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.