> ## 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. # Build World > Builds a World definition from stable Simulator IDs. Start the World to create its Simulations. ## OpenAPI ````yaml /openapi/simulation.yaml post /v1/worlds 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: Create and control isolated runtime instances of ready Simulators. name: simulations x-group: Simulations - description: Build, inspect, and delete reusable Simulator artifacts. name: simulators x-group: Simulators - description: Build and control coordinated groups of Simulations. name: worlds x-group: Worlds paths: /v1/worlds: post: tags: - worlds summary: Build World description: >- Builds a World definition from stable Simulator IDs. Start the World to create its Simulations. operationId: build-world requestBody: content: application/json: schema: $ref: '#/components/schemas/BuildWorldRequest' required: true responses: '202': content: application/json: schema: $ref: '#/components/schemas/World' description: Accepted '400': content: application/problem+json: examples: simulator_unknown: $ref: '#/components/examples/simulator_unknown' schema: $ref: '#/components/schemas/Error' description: Bad Request '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '408': $ref: '#/components/responses/RequestTimeout' '409': content: application/problem+json: examples: simulator_not_ready: $ref: '#/components/examples/simulator_not_ready' schema: $ref: '#/components/schemas/Error' description: Conflict '413': $ref: '#/components/responses/PayloadTooLarge' '415': $ref: '#/components/responses/UnsupportedMediaType' '422': content: application/problem+json: examples: validation: $ref: '#/components/examples/validation' schema: $ref: '#/components/schemas/Error' description: Unprocessable Entity '500': $ref: '#/components/responses/InternalServerError' '503': $ref: '#/components/responses/ServiceUnavailable' security: - apiKeyAuth: [] components: schemas: BuildWorldRequest: additionalProperties: false examples: - instructions: Use stable example data for each Simulator. simulators: - smr_01J8Z5X4K7M2N9P0Q1R2S3T4V5 properties: instructions: description: >- Build guidance. At most 16,384 characters and 65,536 UTF-8 bytes. U+0000 is not permitted. maxLength: 16384 type: string simulators: description: Stable Simulator IDs for the World. items: pattern: ^smr_[0-9A-HJKMNP-TV-Z]{26}$ type: string minItems: 1 type: array required: - simulators type: object World: additionalProperties: false examples: - created_at: '2026-01-15T12:00:00Z' error: null id: wld_01J8Z5X4K7M2N9P0Q1R2S3T4V7 instructions: Use stable example data for each Simulator. simulations: [] simulators: - smr_01J8Z5X4K7M2N9P0Q1R2S3T4V5 status: building properties: created_at: description: Time when the World build started. format: date-time type: string error: $ref: '#/components/schemas/ResourceError' description: Safe failure information, or null when no failure exists. id: description: Stable World ID. pattern: ^wld_[0-9A-HJKMNP-TV-Z]{26}$ type: string instructions: description: Build guidance stored with the World. type: string simulations: description: Created member Simulations. This list is empty before first start. items: $ref: '#/components/schemas/WorldSimulation' type: array simulators: description: Stable Simulator IDs in member order. items: pattern: ^smr_[0-9A-HJKMNP-TV-Z]{26}$ type: string type: array status: description: Current World lifecycle status. enum: - building - ready - running - stopped - failed - canceled type: string required: - id - status - simulators - instructions - simulations - error - created_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 required: - 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: Stable ID of the created Simulation. pattern: ^sim_[0-9A-HJKMNP-TV-Z]{26}$ type: string simulator_id: description: Stable ID of the Simulator that this Simulation runs. pattern: ^smr_[0-9A-HJKMNP-TV-Z]{26}$ type: string required: - id - simulator_id type: object examples: simulator_unknown: value: code: simulator_unknown detail: No Simulator was found with ID "smr_01J8Z5X4K7M2N9P0Q1R2S3T4V5". simulator_not_ready: value: code: simulator_not_ready detail: >- The Simulator with ID "smr_01J8Z5X4K7M2N9P0Q1R2S3T4V5" is not ready. Wait for its build to finish before you retry. validation: value: code: validation detail: The request does not satisfy the API contract. auth_invalid: value: code: auth_invalid detail: The API key is missing or invalid. internal: value: code: internal detail: The server encountered an unexpected error. responses: Unauthorized: content: application/problem+json: examples: auth_invalid: $ref: '#/components/examples/auth_invalid' 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 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 InternalServerError: content: application/problem+json: examples: internal: $ref: '#/components/examples/internal' schema: $ref: '#/components/schemas/Error' description: Internal Server Error ServiceUnavailable: content: application/problem+json: schema: $ref: '#/components/schemas/Error' description: Service Unavailable 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 ````