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

# Set a harness's default connection

> Chooses what your tasks for the harness run on when nothing else says: Aether inference (runs_on aether, Claude Code and Codex only) or a connection you hold (runs_on stored with its connection_id). It takes effect at once: new tasks start on it, and tasks already running resolve their next model calls and secrets through it too. Refused with 409 aether_inference_unserved for Aether inference on OpenCode, 409 connection_harness_mismatch for a connection that does not work with the harness, 409 connection_agent_only for your agent's own ChatGPT login, 409 aether_inference_unavailable where this deployment serves no Aether inference, and 404 connection_not_found for a connection you do not hold.



## OpenAPI

````yaml api-reference/openapi.account.json PUT /connections/defaults/{harness}
openapi: 3.1.0
info:
  title: Aether Account & Integrations API
  version: 0.1.0
  description: >-
    Account, billing, and integration-management endpoints used by the Aether
    web app and CLI. Root-mounted; NOT part of the versioned /v1 contract.
servers:
  - url: https://api.runaether.dev
security:
  - bearerAuth: []
paths:
  /connections/defaults/{harness}:
    put:
      tags:
        - connections
      summary: Set a harness's default connection
      description: >-
        Chooses what your tasks for the harness run on when nothing else says:
        Aether inference (runs_on aether, Claude Code and Codex only) or a
        connection you hold (runs_on stored with its connection_id). It takes
        effect at once: new tasks start on it, and tasks already running resolve
        their next model calls and secrets through it too. Refused with 409
        aether_inference_unserved for Aether inference on OpenCode, 409
        connection_harness_mismatch for a connection that does not work with the
        harness, 409 connection_agent_only for your agent's own ChatGPT login,
        409 aether_inference_unavailable where this deployment serves no Aether
        inference, and 404 connection_not_found for a connection you do not
        hold.
      operationId: setDefaultConnection
      parameters:
        - description: The harness whose tasks the default runs.
          in: path
          name: harness
          required: true
          schema:
            description: The harness whose tasks the default runs.
            enum:
              - claude-code
              - codex
              - opencode
            type: string
      requestBody:
        content:
          application/json:
            schema:
              oneOf:
                - additionalProperties: false
                  properties:
                    runs_on:
                      description: >-
                        Aether inference, paid from your organization's balance:
                        Claude Code and Codex only.
                      enum:
                        - aether
                      type: string
                  required:
                    - runs_on
                  type: object
                - additionalProperties: false
                  properties:
                    connection_id:
                      description: A connection you hold that works with the harness.
                      format: uuid
                      type: string
                    runs_on:
                      description: The connection connection_id names.
                      enum:
                        - stored
                      type: string
                  required:
                    - runs_on
                    - connection_id
                  type: object
        required: true
      responses:
        '200':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ConnectionDefault'
          description: OK
        '400':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Bad Request
        '401':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Unauthorized
        '403':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/OrgAuthorizationErrorResponse'
          description: Forbidden
        '404':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Not Found
        '409':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Conflict
        '422':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Unprocessable Entity
        '500':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Internal Server Error
components:
  schemas:
    ConnectionDefault:
      additionalProperties: false
      properties:
        connection_id:
          description: The connection a stored default runs on.
          format: uuid
          type: string
        harness:
          enum:
            - claude-code
            - codex
            - opencode
          type: string
        runs_on:
          description: >-
            aether, Aether inference, paid from your organization's balance;
            stored, the connection connection_id names.
          enum:
            - aether
            - stored
          type: string
      required:
        - harness
        - runs_on
      type: object
    ErrorResponse:
      additionalProperties: false
      properties:
        code:
          type: string
        error:
          minLength: 1
          type: string
        errors:
          items:
            $ref: '#/components/schemas/ErrorDetail'
          type: array
      required:
        - error
      type: object
    OrgAuthorizationErrorResponse:
      additionalProperties: false
      properties:
        code:
          enum:
            - org_membership_required
            - org_role_insufficient
            - org_suspended
            - account_deleting
          type: string
        error:
          minLength: 1
          type: string
      required:
        - error
        - code
      type: object
    ErrorDetail:
      additionalProperties: false
      properties:
        location:
          description: >-
            Where the error occurred, e.g. 'body.items[3].tags' or
            'path.thing-id'
          type: string
        message:
          description: Error message text
          type: string
        value:
          description: The value at the given location
      type: object
  securitySchemes:
    bearerAuth:
      bearerFormat: JWT
      scheme: bearer
      type: http

````

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