Tags & custom attributes

Two ready-made resource subclasses for projects that use tags and user-defined custom fields.

BaseTagsResource

Adds the m2m tags relation to the response automatically. Use it when your model has a tags ManyToManyField:

from zeromcp.base import BaseTagsResource

class SpaceResource(BaseTagsResource):
    model = Space
    list_fields = ['id', 'name']

Detail responses include "tags": ["foo", "bar"] even when tags is not in edit_fields.

BaseCustomResource

For models that use a custom-attributes pattern (custom fields defined per row, stored through a related model). The class:

• Reads custom-attribute definitions ordered by fieldset.order.
• Groups attributes into named fieldsets (with optional card_type segmentation when the model has a card type).
• Resolves the value for each attribute on the current row.
• Returns a custom_attributes dict on detail responses, structured by fieldset.

Response shape

{
  "id": 42,
  "name": "Some row",
  "ca__priority": "High",
  "custom_attributes": {
    "default": {
      "name": "Default",
      "order": 100000,
      "fields": [{"id": 1, "name": "priority", "value": "High"}]
    },
    "fieldset_a": {
      "name": "Fieldset A",
      "order": 10,
      "hide_if_empty": false,
      "fields": [...]
    }
  }
}

Writing custom values

POST/PATCH bodies accept custom_<name> keys. The library splits them out, runs the regular CRUD pipeline, and saves them via obj._custom.aset(name, value):

POST /spaces
{"name": "Demo", "custom_priority": "High"}

Validation errors raised by the custom field framework bubble as HTTPException(409, message).

0-mcp by Stamatios Stamou Jr — github.com/ssjunior/0-mcp