@micacms/core

Public. From 1.0, semver covers what @micacms/core and @micacms/core/node export. @micacms/core/internal is for Mica's own packages and can change in any release. Pre-1.0: the API and the content format can still change in a minor release.

The core of Mica — a Git-native content editor for static Astro websites: the content model, the format its entries take on disk, and the ContentSource contract that everything reads through.

One model file is the single source of truth for TypeScript types, runtime validation, the CMS's forms, the layout on disk and the Astro collection schemas. Nothing is generated; everything is derived.

import { defineSite, collection, singleton, text, id, richText } from "@micacms/core";

export const site = defineSite({
  collections: {
    news: collection({
      label: "News",
      fields: {
        title: text({ label: "Title", required: true, maxLength: 120 }),
        id: id({ label: "ID", from: "title" }),
        body: richText({ label: "Body" }),
      },
    }),
  },
  singletons: {
    theme: singleton({ label: "Theme", fields: { /* … */ } }),
  },
});

The DSL is not Zod with different spelling. text({ label: "Title", maxLength: 120 }) carries editorial meaning that z.string().max(120) cannot — a label, a width, a group. Zod is generated from the DSL, not the other way round.

What it also decides

• The files on disk. Each entry and each singleton is a folder: index.json, one .mdoc per rich-text field, and media/. serializeEntry and parseEntry are the round trip, and they are byte-stable: equal content produces equal bytes, whatever order the keys arrived in.
• How content is read. A ContentSource is the small interface everything reads through. @micacms/core/node provides fileSystemSource(root) for a working tree.
• How a project describes itself to Mica. createManifest(site, by) wraps the model in a versioned envelope, which @micacms/astro writes to MANIFEST_PATH (.mica/schema.json) inside the content root. Mica reads it from there; nothing else passes between the two.

Install

npm install @micacms/core

zod 4 is a peer dependency. ESM only. Requires Node 24 or newer. Licence: MIT.