> ## Documentation Index
> Fetch the complete documentation index at: https://docs.litellm-agent-platform.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Register a runtime harness



## OpenAPI

````yaml POST /api/runtime-harnesses
openapi: 3.0.3
info:
  title: LiteLLM Agent Platform API
  description: >-
    Unified API for the LiteLLM Agent Platform — gateway, agents, sessions, and
    runtimes.
  version: 0.1.0
servers:
  - url: https://litellm-rust.onrender.com
    description: Production
  - url: http://localhost:4000
    description: Local (Docker Compose)
security:
  - BearerAuth: []
tags:
  - name: System
  - name: Models
  - name: Messages
  - name: API Keys
  - name: Agents
  - name: Sessions
  - name: Runtimes
  - name: MCP
paths:
  /api/runtime-harnesses:
    post:
      tags:
        - Runtimes
      summary: Register a runtime harness
      operationId: createRuntimeHarness
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/UpdateRuntimeHarnessRequest'
      responses:
        '200':
          description: Runtime registered
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RuntimeHarnessesResponse'
        '401':
          description: Unauthorized
      security:
        - BearerAuth: []
components:
  schemas:
    UpdateRuntimeHarnessRequest:
      type: object
      properties:
        api_base:
          type: string
          example: http://opencode:8080
        api_key:
          type: string
          example: local-opencode-key
    RuntimeHarnessesResponse:
      type: object
      properties:
        harnesses:
          type: array
          items:
            $ref: '#/components/schemas/RuntimeHarness'
    RuntimeHarness:
      type: object
      properties:
        alias:
          type: string
          example: local-opencode
        api_spec:
          type: string
          enum:
            - claude_managed_agents
            - cursor
            - gemini_antigravity
            - elastic_agent_builder
          example: claude_managed_agents
        display_name:
          type: string
          example: local-opencode
        api_base:
          type: string
          example: http://opencode:8080
        is_default:
          type: boolean
        connected:
          type: boolean
        masked_api_key:
          type: string
          nullable: true
        tools:
          type: array
          items:
            type: object
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      description: 'Your LITELLM_MASTER_KEY. Default for local Docker Compose: `sk-local`'

````