Frontmatter & tagging schemas
for extraction in Obsidian

import { defineCollection, reference, z } from 'astro:content';

const notes = defineCollection({
  schema: z.object({
    title:   z.string(),
    created: z.coerce.date(),
    tags:    z.array(z.string()),
    status:  z.enum(['active', 'archived', 'done']),
    author:  reference('authors'),
  }),
});

z.coerce.date() converts ISO → JS Date. reference() cross-validates wikilinks. Eleventy v3 mirrors via eleventyDataSchema^[36]. astro-editor ⭐ 445 turns the same schema into a typed form^[43].

from enum import Enum
from pydantic import BaseModel
from pydantic_yaml import parse_yaml_raw_as

class Status(str, Enum):
    active   = "active"
    archived = "archived"
    done     = "done"

class Note(BaseModel):
    title:  str
    status: Status = Status.active
    tags:   list[str] = []

pydantic_yaml round-trips via parse_yaml_raw_as()/to_yaml_str()^[42]. Lighter alternative: Yamale ⭐ 764 ships str(), int(min,max), day(), enum(), regex(), include()^[38].

# mdschema · ./schema.yaml
- { name: "title",  type: string }
- { name: "created",type: date,
   format: date }
- { name: "author", optional: true,
   format: email }
- { name: "tags",   optional: true,
   type: array }

remark-lint-frontmatter-schema validates against JSON Schema in a remark pipeline; supports per-file $schema, IDE underlining, auto-fix^[37]. Stack with markdownlint-cli2 via its frontMatter regex skip^[44].