---

name: secondbrain-entity description: | This skill should be used when the user asks to "add entity", "create custom entity", "new entity type", "define entity", or mentions wanting to add a new trackable data type to their secondbrain project beyond the predefined ADR, Note, Task, and Discussion types.

Add Custom Entity

Create custom entity types with schema validation and VitePress integration.

Prerequisites

Verify secondbrain is initialized:

1. Check for .claude/data/config.yaml
2. If not found, suggest running secondbrain-init first

Workflow

Step 1: Gather Entity Information

Collect from user:

1. Entity Name — Plural name (e.g., "contacts", "projects", "bookmarks")
2. Singular Name — For display (e.g., "contact", "project", "bookmark")
3. Fields — Custom fields for the entity:
   • Field name (snake_case)
   • Field type (string, integer, boolean, date, array, enum)
   • Required or optional
   • For enums: allowed values
4. ID Format — How records are numbered/identified:
   • Sequential (PREFIX-XXXX)
   • Date-based (YYYY-MM-DD-slug)
   • UUID
5. Status Workflow (optional) — If entity has status tracking

Step 2: Generate Schema

Create .claude/data/<entity>/schema.yaml:

type: object
required: [records]
properties:
  last_number:
    type: integer
    description: Last assigned sequential number
  records:
    type: array
    items:
      type: object
      required: [id, title, created, file]
      properties:
        id:
          type: string
          description: Unique identifier
        title:
          type: string
          description: Display title
        created:
          type: string
          format: date
        file:
          type: string
          description: Path to markdown file
        status:
          type: string
          enum: [active, archived]
        # ... custom fields

Step 3: Initialize Records File

Create .claude/data/<entity>/records.yaml:

last_number: 0
records: []

Step 4: Create Document Template

Create templates/entities/<entity>/TEMPLATE.md:

---
id: {{id}}
title: {{title}}
created: {{date}}
status: active
# ... custom fields
---

# {{title}}

## Overview

[Description]

## Details

[Content]

Step 5: Create VitePress Data Loader

Create docs/.vitepress/data/<entity>.data.ts:

import { defineLoader } from 'vitepress'
import fs from 'fs'
import yaml from 'js-yaml'

interface Record {
  id: string
  title: string
  created: string
  file: string
  status: string
  // ... custom fields
}

export interface Data {
  records: Record[]
  lastNumber: number
}

declare const data: Data
export { data }

export default defineLoader({
  watch: ['.claude/data/<entity>/*.yaml'],
  async load(): Promise<Data> {
    const recordsPath = '.claude/data/<entity>/records.yaml'

    if (!fs.existsSync(recordsPath)) {
      return { records: [], lastNumber: 0 }
    }

    const content = fs.readFileSync(recordsPath, 'utf-8')
    const parsed = yaml.load(content) as any

    return {
      records: parsed.records || [],
      lastNumber: parsed.last_number || 0
    }
  }
})

Step 6: Create Documentation Index

Create docs/<entity>/index.md:

---
title: <Entity> Index
---

# <Entity>

<script setup>
import { data } from '../.vitepress/data/<entity>.data'
import EntityTable from '../.vitepress/theme/components/EntityTable.vue'

const columns = [
  { key: 'id', label: 'ID', sortable: true },
  { key: 'title', label: 'Title', sortable: true },
  { key: 'created', label: 'Created', sortable: true },
  { key: 'status', label: 'Status', sortable: true }
]
</script>

<EntityTable :data="data.records" :columns="columns" />

Step 7: Update Configuration

Add entity to .claude/data/config.yaml:

entities:
  <entity>:
    enabled: true
    singular: <singular>
    id_format: sequential  # or date-based, uuid
    prefix: PREFIX         # for sequential IDs
    freshness:
      stale_after_days: 30
    fields:
      - name: field_name
        type: string
        required: true

Step 8: Update Sidebar

Add to docs/.vitepress/config.ts sidebar:

{
  text: '<Entity>',
  collapsed: true,
  items: [
    { text: 'Overview', link: '/<entity>/' }
  ]
}

Step 9: Confirm Creation

## Entity Created

**Name:** <entity>
**Singular:** <singular>
**ID Format:** sequential (PREFIX-XXXX)
**Status Tracking:** Yes

### Fields
| Field | Type | Required |
|-------|------|----------|
| title | string | Yes |
| description | string | No |
| priority | enum (low, medium, high) | No |

### Files Created
- `.claude/data/<entity>/schema.yaml`
- `.claude/data/<entity>/records.yaml`
- `docs/.vitepress/data/<entity>.data.ts`
- `docs/<entity>/index.md`

### Next Steps
1. Create records using the new entity type
2. Add entity-specific skills if needed
3. Customize the index page layout

Field Types

Type	YAML Schema	Example
string	type: string	"Hello world"
integer	type: integer	42
number	type: number	3.14
boolean	type: boolean	true/false
date	type: string, format: date	2026-01-15
datetime	type: string, format: date-time	2026-01-15T10:30:00Z
array	type: array, items: {...}	[tag1, tag2]
enum	type: string, enum: [...]	"active"

ID Formats

Sequential

Best for: Tasks, tickets, numbered records

PREFIX-0001, PREFIX-0002, PREFIX-0003

Date-based

Best for: Notes, journal entries, time-sensitive content

2026-01-15-meeting-notes
2026-01-15-architecture-review

UUID

Best for: Globally unique, import/export scenarios

550e8400-e29b-41d4-a716-446655440000

Tips

1. Keep fields minimal — Start with essential fields, add more later
2. Use enums for fixed values — Better than free-form strings
3. Consider status workflow — Most entities benefit from status tracking
4. Plan ID format carefully — Hard to change after records exist
5. Reuse existing patterns — Look at ADR, Task, Note for inspiration