> ## Documentation Index > Fetch the complete documentation index at: https://developers.meshapi.ai/llms.txt > Use this file to discover all available pages before exploring further. # Router Select > Resolve the Auto Router's model choice for a prompt without running inference. ## OpenAPI ````yaml /api/openapi.json post /v1/router/select openapi: 3.1.0 info: title: MeshAPI description: One key, all AI models. version: 0.1.0 servers: - url: https://api.meshapi.ai security: - BearerAuth: [] paths: /v1/router/select: post: tags: - Router summary: Router Select description: >- Resolve the Auto Router's model choice for a prompt without running inference. operationId: router_select parameters: - in: header name: X-Mesh-Version required: false schema: type: string enum: - 2026-08 default: 2026-08 example: 2026-08 description: >- Dated version of the API contract to pin this request to. Omit it and the request is served under `2026-08` — the oldest supported version, so an existing integration is never moved by a release. A malformed or unsupported value is rejected with `400 invalid_api_version` rather than falling back silently. The version actually served is echoed as `X-Mesh-Version` on every response, including errors. requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/RouterSelectRequest' examples: default: summary: Example request value: messages: - role: user content: Write a SQL query for monthly revenue. api_type: completions exclude_models: - openai/gpt-4o-mini responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/RouterSelectResponse' examples: default: summary: Example response value: model: anthropic/claude-haiku-4.5 auto_router: selected: true strategy: registry reason: Best latency-adjusted fit for the prompt and API type. reasoning_effort: none '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' security: - BearerAuth: [] components: schemas: RouterSelectRequest: properties: messages: items: $ref: '#/components/schemas/Message' type: array minItems: 1 title: Messages api_type: type: string enum: - completions - responses - embeddings title: Api Type default: completions exclude_models: anyOf: - items: type: string type: array - type: 'null' title: Exclude Models candidate_models: anyOf: - items: type: string type: array - type: 'null' title: Candidate Models type: object required: - messages title: RouterSelectRequest RouterSelectResponse: properties: model: type: string title: Model auto_router: $ref: '#/components/schemas/AutoRouterMeta' reasoning_effort: anyOf: - type: string enum: - high - medium - low - none - type: 'null' title: Reasoning Effort type: object required: - model - auto_router title: RouterSelectResponse HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError Message: properties: role: type: string enum: - system - user - assistant - tool title: Role content: anyOf: - type: string - items: $ref: '#/components/schemas/ContentPart' type: array - type: 'null' title: Content name: anyOf: - type: string - type: 'null' title: Name tool_call_id: anyOf: - type: string - type: 'null' title: Tool Call Id tool_calls: anyOf: - items: $ref: '#/components/schemas/ToolCall' type: array - type: 'null' title: Tool Calls reasoning_details: anyOf: - items: additionalProperties: true type: object type: array - type: 'null' title: Reasoning Details cache_control: anyOf: - additionalProperties: true type: object - type: 'null' title: Cache Control type: object required: - role title: Message AutoRouterMeta: properties: fallback_used: type: boolean title: Fallback Used default: false fallback_reason: anyOf: - type: string - type: 'null' title: Fallback Reason type: object title: AutoRouterMeta ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type input: title: Input ctx: type: object title: Context type: object required: - loc - msg - type title: ValidationError ContentPart: properties: type: type: string enum: - text - image_url - video_url - input_audio title: Type text: anyOf: - type: string - type: 'null' title: Text image_url: anyOf: - $ref: '#/components/schemas/ImageUrl' - type: 'null' video_url: anyOf: - $ref: '#/components/schemas/VideoUrl' - type: 'null' input_audio: anyOf: - $ref: '#/components/schemas/InputAudio' - type: 'null' fps: anyOf: - type: string - type: 'null' title: Fps cache_control: anyOf: - additionalProperties: true type: object - type: 'null' title: Cache Control type: object required: - type title: ContentPart ToolCall: properties: id: type: string title: Id type: type: string const: function title: Type default: function function: additionalProperties: true type: object title: Function thought_signature: anyOf: - type: string - type: 'null' title: Thought Signature type: object required: - id - function title: ToolCall ImageUrl: properties: url: type: string title: Url detail: type: string enum: - auto - low - high title: Detail default: auto type: object required: - url title: ImageUrl VideoUrl: properties: url: type: string title: Url type: object required: - url title: VideoUrl InputAudio: properties: data: anyOf: - type: string - type: 'null' title: Data uri: anyOf: - type: string - type: 'null' title: Uri url: anyOf: - type: string - type: 'null' title: Url format: type: string enum: - wav - mp3 - aiff - aac - ogg - flac - m4a - pcm16 - pcm24 title: Format type: object required: - format title: InputAudio securitySchemes: BearerAuth: type: http scheme: bearer description: >- Enter your MeshAPI key (`rsk_...`) — sent as `Authorization: Bearer `. ````