Obsidian Properties

Properties are structured metadata stored as YAML frontmatter at the top of notes. They enable organization, search, filtering, and integration with features like Bases, Templates, and Search.

Always use the update_frontmatter tool for property changes — it handles YAML formatting safely via Obsidian's API.

Property Format

Properties are YAML between --- delimiters at the very start of a file:

---
title: My Note
tags:
  - journal
  - personal
date: 2024-08-21
---

• Each property name must be unique within a note
• Names are separated from values by a colon followed by a space
• Order of properties doesn't matter

Property Types

Once a type is assigned to a property name, all notes in the vault share that type.

Text

Single line of text. No markdown rendering. Hashtags do NOT create tags.

Internal links must be quoted:

title: A New Hope
link: '[[Episode IV]]'
url: https://www.example.com

List

Multiple values, each on its own line with - :

cast:
  - Mark Hamill
  - Harrison Ford
  - Carrie Fisher
links:
  - '[[Link]]'
  - '[[Link2]]'

Internal links in lists must also be quoted.

Number

Literal integers or decimals only — no expressions or operators:

year: 1977
pie: 3.14

Checkbox

Boolean true or false. Renders as a checkbox in Live Preview:

favorite: true
reply: false

Date

Format: YYYY-MM-DD

date: 2024-08-21

With the Daily Notes plugin enabled, date properties function as internal links to daily notes.

Date & Time

Format: YYYY-MM-DDTHH:mm:ss

time: 2024-08-21T10:30:00

Tags

Special type used exclusively by the tags property. Cannot be assigned to other property names. Formatted as a list:

tags:
  - journal
  - personal
  - draft

Default Properties

Property	Type	Description
tags	List	Note tags (also recognized inline with #tag)
aliases	List	Alternative names for the note (used in link resolution)
cssclasses	List	Apply CSS snippets to style individual notes

Obsidian Publish Properties

Property	Description
publish	Whether to publish the note
permalink	Custom URL path
description	Page description
image / cover	Page image

Deprecated Properties (removed in Obsidian 1.9)

Use the modern equivalents instead:

• tag → use tags
• alias → use aliases
• cssclass → use cssclasses

JSON Format

Properties can also be defined as JSON (will be converted to YAML on save):

---
{ 'tags': ['journal'], 'publish': false }
---

Best Practices

When Modifying Properties

• Always use update_frontmatter — never manually edit YAML via write_file
• Use canonical names: tags not tag, aliases not alias, cssclasses not cssclass
• Quote internal links: "[[Note Name]]" in both text and list properties
• Use proper date format: YYYY-MM-DD for dates, YYYY-MM-DDTHH:mm:ss for datetimes
• Numbers must be literals — no expressions like 1+1

When Writing File Content

• Never place content above or inside the frontmatter block
• "Top of the note" means after the closing ---, not the first line of the file
• Preserve existing frontmatter exactly when using write_file

Property Design Patterns

• Use tags for broad categorization (searchable, filterable in Bases)
• Use custom properties for structured data (status, priority, due dates)
• Use aliases so notes can be found by alternative names
• Use cssclasses to visually distinguish note types (e.g., dashboard, daily-note)
• Keep property names consistent across your vault — Obsidian enforces type consistency per name

Integration with Bases

Properties are the foundation of Bases views. Note properties are accessed as note.property_name or just property_name in Base filters and formulas. Design your property schema with Bases queries in mind.

Limitations

• No nested properties — use Source mode to view nested YAML if needed
• No bulk editing — use external tools or community plugins for mass property changes
• No markdown in properties — properties are meant for small, atomic, machine-readable data
• No duplicate names — each property name can only appear once per note