Details of all options available in config.json

When adding a new app to the Companion App Store, you need to create a config.json file in the app’s folder. This file contains all the information needed to run the app. Below you can find all the options available in the config.json file.

Sometimes an app requires additional information to run, such as a username or a password. You can leverage the form_fields property in the config.json file to request that information. Here’s an example:

{
  "form_fields": [
    {
      "type": "text",
      "label": "Username",
      "max": 50,
      "min": 3,
      "required": true,
      "env_variable": "NEXTCLOUD_ADMIN_USER"
    },
    {
      "type": "password",
      "label": "Password",
      "max": 50,
      "min": 3,
      "required": true,
      "env_variable": "NEXTCLOUD_ADMIN_PASSWORD"
    }
  ]
}

You can choose between different types of fields. The app will automatically validate the user input before submitting.

Here is a table of the available form_field properties:

Using options in form fields

You can create a form field with options like this in your config.json. It will be rendered as a multi-select dropdown in the UI. label is what will be shown to the user and value is the actual value the environment variable will be set to when the corresponding option is selected.

Hub integration (hub_integration)

Apps can opt in to Hub-provided environment variables and services.

MCP client

Agent apps that connect to Hub MCP set:

{
  "hub_integration": {
    "mcp_client": true,
    "wake_endpoint": "/hooks/hub-wake",
    "wake_port": 3000,
    "sse_events": false
  }
}

When enabled, Hub injects HUB_URL, HUB_MCP_URL, HUB_MCP_MESSAGES_URL, HUB_MCP_API_KEY, and HUB_WAKE_SECRET into the app’s environment.

Inference variables

AI apps map standardized Hub inference keys to their own env variable names:

{
  "hub_integration": {
    "inference": {
      "llm_base_url": "LLM_API_BASE",
      "llm_api_key": "LLM_API_KEY",
      "chat_model": "LLM_DEFAULT_CHAT_MODEL",
      "embedding_model": "LLM_DEFAULT_EMBEDDING_MODEL",
      "vision_model": "LLM_DEFAULT_VISION_MODEL",
      "ollama_host": "OLLAMA_HOST"
    }
  }
}

See AI & Inference for resolution order and setup.

{ 
   "label": "Select your favorite fruits", 
   "type": "text", 
   "required": true, 
   "options": [ 
       { "label": "Apple", "value": "apple" }, 
       { "label": "Banana", "value": "banana" }, 
       { "label": "Orange", "value": "orange" } 
   ], 
   "env_variable": "fruits" 
}