> ## 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. # Fork a running Simulation at head or at a step > Creates a new Simulation from the current head or a recorded step. The source Simulation keeps running. ## OpenAPI ````yaml /openapi/simulation.yaml post /v1/simulations/{id}/fork openapi: 3.1.0 info: description: >- The continuous-simulation API builds reusable Simulators and runs isolated Simulations and Worlds. This document describes the stable v1 public contract. title: continuous-simulation API version: v1 servers: - description: Continuous production API. url: https://api.continuouslabs.ai security: [] tags: - description: Read deployment metadata for the public API. name: meta x-group: API metadata - description: Create and control isolated runtime instances of ready Simulators. name: simulations x-group: Simulations - description: Build, inspect, tag, publish, and delete reusable Simulator artifacts. name: simulators x-group: Simulators - description: Upload and publish Simulator artifacts. name: uploads x-group: Artifact uploads - description: Create and control coordinated groups of Simulations. name: worlds x-group: Worlds paths: /v1/simulations/{id}/fork: post: tags: - simulations summary: Fork a running Simulation at head or at a step description: >- Creates a new Simulation from the current head or a recorded step. The source Simulation keeps running. operationId: fork-simulation parameters: - in: header name: X-Forwarded-Proto schema: type: string - in: path name: id required: true schema: type: string - description: >- Required with a sealed session on workspace-scoped routes. API keys carry their workspace. in: header name: X-Workspace-Id schema: type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/ForkSimulationRequest' required: true responses: '200': content: application/json: schema: $ref: '#/components/schemas/Simulation' description: OK '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '408': $ref: '#/components/responses/RequestTimeout' '409': $ref: '#/components/responses/Conflict' '413': $ref: '#/components/responses/PayloadTooLarge' '415': $ref: '#/components/responses/UnsupportedMediaType' '422': $ref: '#/components/responses/UnprocessableEntity' '429': $ref: '#/components/responses/TooManyRequests' '500': $ref: '#/components/responses/InternalServerError' '503': $ref: '#/components/responses/ServiceUnavailable' '504': $ref: '#/components/responses/GatewayTimeout' security: - apiKeyAuth: [] - sessionBearerAuth: [] - sessionCookie: [] components: schemas: ForkSimulationRequest: additionalProperties: false examples: - at_step: 42 name: billing-fork properties: $schema: description: A URL to the JSON Schema for this object. examples: - https://example.com/schemas/ForkSimulationRequest.json format: uri readOnly: true type: string at_step: format: int64 maximum: 9007199254740991 minimum: 0 type: integer name: type: string type: object Simulation: additionalProperties: false examples: - clock_start: '2026-01-15T12:00:00Z' created_at: '2026-01-15T12:00:00Z' endpoint: https://api.continuouslabs.ai/sim/sim_01J8Z5X4K7M2N9P0Q1R2S3T4V6 id: sim_01J8Z5X4K7M2N9P0Q1R2S3T4V6 labels: environment: demo name: billing-sandbox parent: '' seed: demo-seed simulator_id: smr_01J8Z5X4K7M2N9P0Q1R2S3T4V5 status: running token: properties: $schema: description: A URL to the JSON Schema for this object. examples: - https://example.com/schemas/Simulation.json format: uri readOnly: true type: string clock_start: format: date-time type: string created_at: format: date-time type: string endpoint: type: string id: type: string labels: additionalProperties: type: string type: object name: type: string parent: type: string seed: type: string simulator_id: type: string status: enum: - running - paused - stopped type: string token: type: string required: - id - name - simulator_id - parent - seed - clock_start - status - endpoint - token - labels - created_at type: object Error: additionalProperties: false examples: - code: simulator_not_ready detail: simulator is not ready properties: code: minLength: 1 type: string detail: minLength: 1 type: string required: - code - detail type: object responses: BadRequest: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Bad Request Unauthorized: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Unauthorized Forbidden: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Forbidden NotFound: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Not Found RequestTimeout: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Request Timeout Conflict: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Conflict PayloadTooLarge: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Request Entity Too Large UnsupportedMediaType: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Unsupported Media Type UnprocessableEntity: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Unprocessable Entity TooManyRequests: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Too Many Requests InternalServerError: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Internal Server Error ServiceUnavailable: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Service Unavailable GatewayTimeout: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Gateway Timeout 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 sessionBearerAuth: bearerFormat: sealed session description: >- Use a sealed user session Bearer token. This method supports browser and session-only operations. scheme: bearer type: http sessionCookie: description: >- Use the sealed browser session cookie. This method supports browser and session-only operations. in: cookie name: wos-session type: apiKey ````