> ## Documentation Index > Fetch the complete documentation index at: https://docs.usetuner.ai/llms.txt > Use this file to discover all available pages before exploring further. # Create Run > Start a simulation run for an agent. Simulations generate synthetic test calls against the agent's current configuration and grade them using its `PASS_FAIL` evals. The agent needs at least one `PASS_FAIL` eval configured before a run can start. Returns immediately with the run in `pending` state and `generated_count` of zero — scenario generation runs asynchronously. Poll List Runs for progress. ## OpenAPI ````yaml https://api.usetuner.ai/public/openapi.json post /api/v1/workspaces/{workspace_id}/agents/{agent_id}/simulation-runs openapi: 3.1.0 info: title: My Public API version: 1.0.0 servers: - url: https://api.usetuner.ai security: [] tags: - name: calls x-group: Calls - name: workspaces x-group: Workspaces - name: agent-settings x-group: Agent Settings - name: agents x-group: Agents - name: simulation x-group: Simulation - name: providers x-group: Providers paths: /api/v1/workspaces/{workspace_id}/agents/{agent_id}/simulation-runs: post: tags: - simulation summary: Create Run description: >- Start a simulation run for an agent. Simulations generate synthetic test calls against the agent's current configuration and grade them using its `PASS_FAIL` evals. The agent needs at least one `PASS_FAIL` eval configured before a run can start. Returns immediately with the run in `pending` state and `generated_count` of zero — scenario generation runs asynchronously. Poll List Runs for progress. operationId: >- create_simulation_run_api_v1_workspaces__workspace_id__agents__agent_id__simulation_runs_post parameters: - name: agent_id in: path required: true schema: type: integer description: Tuner's internal numeric ID for the agent. title: Agent Id description: Tuner's internal numeric ID for the agent. - name: workspace_id in: path required: true schema: type: integer description: Workspace ID. Find this in Workspace > General Settings. title: Workspace Id description: Workspace ID. Find this in Workspace > General Settings. requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CreateSimulationRunRequest' responses: '202': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/SimulationRunResponse' '400': description: >- `caller_persona_id` or `simulation_profile_id` does not exist, or the profile belongs to a different agent. content: application/json: example: detail: >- Invalid simulation_profile_id or profile does not belong to this agent schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Missing or invalid API key. content: application/json: example: detail: Not authenticated schema: $ref: '#/components/schemas/ErrorResponse' '402': description: >- The workspace has no credits remaining, or its plan does not include simulations. content: application/json: example: detail: You have no credits remaining. schema: $ref: '#/components/schemas/ErrorResponse' '403': description: You do not have access to this workspace. content: application/json: example: detail: User does not have access to workspace 42 schema: $ref: '#/components/schemas/ErrorResponse' '404': description: Agent not found. content: application/json: example: detail: Agent with ID 17 not found schema: $ref: '#/components/schemas/ErrorResponse' '409': description: A simulation run is already in progress for this agent. content: application/json: example: detail: You have a simulation run in progress. Come back later. schema: $ref: '#/components/schemas/ErrorResponse' '422': description: >- The agent has no settings configured, its provider does not support simulations for its call direction, or it has no `PASS_FAIL` eval configured. content: application/json: example: detail: >- Agent has no boolean (PASS_FAIL) evals. Add at least one before running a simulation. schema: $ref: '#/components/schemas/ErrorResponse' security: - Bearer: [] components: schemas: CreateSimulationRunRequest: properties: functional_count: type: integer minimum: 0 title: Functional Count adversarial_count: type: integer minimum: 0 title: Adversarial Count max_call_duration_minutes: type: integer maximum: 12 minimum: 1 title: Max Call Duration Minutes default: 3 selected_eval_ids: anyOf: - items: type: integer type: array - type: 'null' title: Selected Eval Ids selected_intent_ids: anyOf: - items: type: integer type: array - type: 'null' title: Selected Intent Ids caller_persona_id: type: integer title: Caller Persona Id simulation_profile_id: anyOf: - type: integer exclusiveMinimum: 0 - type: 'null' title: Simulation Profile Id type: object required: - functional_count - adversarial_count - caller_persona_id title: CreateSimulationRunRequest SimulationRunResponse: properties: simulation_run_id: type: integer title: Simulation Run Id generated_count: type: integer title: Generated Count success: type: boolean title: Success caller_persona_id: anyOf: - type: integer - type: 'null' title: Caller Persona Id caller_persona: anyOf: - $ref: '#/components/schemas/CallerPersonaResponse' - type: 'null' simulation_profile_id: anyOf: - type: integer - type: 'null' title: Simulation Profile Id simulation_profile_name: anyOf: - type: string - type: 'null' title: Simulation Profile Name simulation_profile_snapshot: anyOf: - additionalProperties: true type: object - type: 'null' title: Simulation Profile Snapshot type: object required: - simulation_run_id - generated_count - success title: SimulationRunResponse ErrorResponse: properties: detail: type: string title: Detail description: Human-readable description of what went wrong. type: object required: - detail title: ErrorResponse description: Error body returned when a request fails. CallerPersonaResponse: properties: id: type: integer title: Id name: type: string title: Name language: type: string title: Language language_code: type: string title: Language Code accent: type: string title: Accent label: type: string title: Label country_code: type: string title: Country Code type: object required: - id - name - language - language_code - accent - label - country_code title: CallerPersonaResponse securitySchemes: Bearer: type: http description: >- Use Tuner API key (tr_api_...) or user session token. Find your API key in Workspace Settings > API Keys. scheme: bearer ````