Obsidian Bases Skill

This skill enables skills-compatible agents to create and edit valid Obsidian Bases (.base files) including views, filters, formulas, and all related configurations.

Overview

Obsidian Bases are YAML-based files that define dynamic views of notes in an Obsidian vault. A Base file can contain multiple views, global filters, formulas, property configurations, and custom summaries.

File Format

Base files use the .base extension and contain valid YAML. They can also be embedded in Markdown code blocks.

Complete Schema

Global filters apply to ALL views in the base

filters:

Can be a single filter string

OR a recursive filter object with and/or/not

and: [] or: [] not: []

Define formula properties that can be used across all views

formulas: formula_name: 'expression'

Configure display names and settings for properties

properties: property_name: displayName: "Display Name" formula.formula_name: displayName: "Formula Display Name" file.ext: displayName: "Extension"

Define custom summary formulas

summaries: custom_summary_name: 'values.mean().round(3)'

Define one or more views

views:

• type: table | cards | list | map name: "View Name" limit: 10 # Optional: limit results groupBy: # Optional: group results property: property_name direction: ASC | DESC filters: # View-specific filters and: [] order: # Properties to display in order
  • file.name
  • property_name
  • formula.formula_name summaries: # Map properties to summary formulas property_name: Average

Filter Syntax

Filters narrow down results. They can be applied globally or per-view.

Filter Structure

Single filter

filters: 'status == "done"'

AND - all conditions must be true

filters: and: - 'status == "done"' - 'priority > 3'

OR - any condition can be true

filters: or: - 'file.hasTag("book")' - 'file.hasTag("article")'

NOT - exclude matching items

filters: not: - 'file.hasTag("archived")'

Nested filters

filters: or: - file.hasTag("tag") - and: - file.hasTag("book") - file.hasLink("Textbook") - not: - file.hasTag("book") - file.inFolder("Required Reading")

Filter Operators

Operator Description

==

equals

!=

not equal

greater than

<

less than

=

greater than or equal

<=

less than or equal

&&

logical and

||

logical or

! logical not

Properties

Three Types of Properties

• Note properties - From frontmatter: note.author or just author

• File properties - File metadata: file.name , file.mtime , etc.

• Formula properties - Computed values: formula.my_formula

File Properties Reference

Property Type Description

file.name

String File name

file.basename

String File name without extension

file.path

String Full path to file

file.folder

String Parent folder path

file.ext

String File extension

file.size

Number File size in bytes

file.ctime

Date Created time

file.mtime

Date Modified time

file.tags

List All tags in file

file.links

List Internal links in file

file.backlinks

List Files linking to this file

file.embeds

List Embeds in the note

file.properties

Object All frontmatter properties

The this Keyword

• In main content area: refers to the base file itself

• When embedded: refers to the embedding file

• In sidebar: refers to the active file in main content

Formula Syntax

Formulas compute values from properties. Defined in the formulas section.

formulas:

Simple arithmetic

total: "price * quantity"

Conditional logic

status_icon: 'if(done, "✅", "⏳")'

String formatting

formatted_price: 'if(price, price.toFixed(2) + " dollars")'

Date formatting

created: 'file.ctime.format("YYYY-MM-DD")'

Complex expressions

days_old: '((now() - file.ctime) / 86400000).round(0)'

Functions Reference

Global Functions

Function Signature Description

date()

date(string): date

Parse string to date. Format: YYYY-MM-DD HH:mm:ss

duration()

duration(string): duration

Parse duration string

now()

now(): date

Current date and time

today()

today(): date

Current date (time = 00:00:00)

if()

if(condition, trueResult, falseResult?)

Conditional

min()

min(n1, n2, ...): number

Smallest number

max()

max(n1, n2, ...): number

Largest number

number()

number(any): number

Convert to number

link()

link(path, display?): Link

Create a link

list()

list(element): List

Wrap in list if not already

file()

file(path): file

Get file object

image()

image(path): image

Create image for rendering

icon()

icon(name): icon

Lucide icon by name

html()

html(string): html

Render as HTML

escapeHTML()

escapeHTML(string): string

Escape HTML characters

Any Type Functions

Function Signature Description

isTruthy()

any.isTruthy(): boolean

Coerce to boolean

isType()

any.isType(type): boolean

Check type

toString()

any.toString(): string

Convert to string

Date Functions & Fields

Fields: date.year , date.month , date.day , date.hour , date.minute , date.second , date.millisecond

Function Signature Description

date()

date.date(): date

Remove time portion

format()

date.format(string): string

Format with Moment.js pattern

time()

date.time(): string

Get time as string

relative()

date.relative(): string

Human-readable relative time

isEmpty()

date.isEmpty(): boolean

Always false for dates

Date Arithmetic

Duration units: y/year/years, M/month/months, d/day/days,

w/week/weeks, h/hour/hours, m/minute/minutes, s/second/seconds

Add/subtract durations

"date + "1M"" # Add 1 month "date - "2h"" # Subtract 2 hours "now() + "1 day"" # Tomorrow "today() + "7d"" # A week from today

Subtract dates for millisecond difference

"now() - file.ctime"

Complex duration arithmetic

"now() + (duration('1d') * 2)"

String Functions

Field: string.length

Function Signature Description

contains()

string.contains(value): boolean

Check substring

containsAll()

string.containsAll(...values): boolean

All substrings present

containsAny()

string.containsAny(...values): boolean

Any substring present

startsWith()

string.startsWith(query): boolean

Starts with query

endsWith()

string.endsWith(query): boolean

Ends with query

isEmpty()

string.isEmpty(): boolean

Empty or not present

lower()

string.lower(): string

To lowercase

title()

string.title(): string

To Title Case

trim()

string.trim(): string

Remove whitespace

replace()

string.replace(pattern, replacement): string

Replace pattern

repeat()

string.repeat(count): string

Repeat string

reverse()

string.reverse(): string

Reverse string

slice()

string.slice(start, end?): string

Substring

split()

string.split(separator, n?): list

Split to list

Number Functions

Function Signature Description

abs()

number.abs(): number

Absolute value

ceil()

number.ceil(): number

Round up

floor()

number.floor(): number

Round down

round()

number.round(digits?): number

Round to digits

toFixed()

number.toFixed(precision): string

Fixed-point notation

isEmpty()

number.isEmpty(): boolean

Not present

List Functions

Field: list.length

Function Signature Description

contains()

list.contains(value): boolean

Element exists

containsAll()

list.containsAll(...values): boolean

All elements exist

containsAny()

list.containsAny(...values): boolean

Any element exists

filter()

list.filter(expression): list

Filter by condition (uses value , index )

map()

list.map(expression): list

Transform elements (uses value , index )

reduce()

list.reduce(expression, initial): any

Reduce to single value (uses value , index , acc )

flat()

list.flat(): list

Flatten nested lists

join()

list.join(separator): string

Join to string

reverse()

list.reverse(): list

Reverse order

slice()

list.slice(start, end?): list

Sublist

sort()

list.sort(): list

Sort ascending

unique()

list.unique(): list

Remove duplicates

isEmpty()

list.isEmpty(): boolean

No elements

File Functions

Function Signature Description

asLink()

file.asLink(display?): Link

Convert to link

hasLink()

file.hasLink(otherFile): boolean

Has link to file

hasTag()

file.hasTag(...tags): boolean

Has any of the tags

hasProperty()

file.hasProperty(name): boolean

Has property

inFolder()

file.inFolder(folder): boolean

In folder or subfolder

Link Functions

Function Signature Description

asFile()

link.asFile(): file

Get file object

linksTo()

link.linksTo(file): boolean

Links to file

Object Functions

Function Signature Description

isEmpty()

object.isEmpty(): boolean

No properties

keys()

object.keys(): list

List of keys

values()

object.values(): list

List of values

Regular Expression Functions

Function Signature Description

matches()

regexp.matches(string): boolean

Test if matches

View Types

Table View

views:

• type: table name: "My Table" order:
  • file.name
  • status
  • due_date summaries: price: Sum count: Average

Cards View

views:

• type: cards name: "Gallery" order:
  • file.name
  • cover_image
  • description

List View

views:

• type: list name: "Simple List" order:
  • file.name
  • status

Map View

Requires latitude/longitude properties and the Maps community plugin.

views:

• type: map name: "Locations"

  Map-specific settings for lat/lng properties

Default Summary Formulas

Name Input Type Description

Average

Number Mathematical mean

Min

Number Smallest number

Max

Number Largest number

Sum

Number Sum of all numbers

Range

Number Max - Min

Median

Number Mathematical median

Stddev

Number Standard deviation

Earliest

Date Earliest date

Latest

Date Latest date

Range

Date Latest - Earliest

Checked

Boolean Count of true values

Unchecked

Boolean Count of false values

Empty

Any Count of empty values

Filled

Any Count of non-empty values

Unique

Any Count of unique values

Complete Examples

Task Tracker Base

filters: and: - file.hasTag("task") - 'file.ext == "md"'

formulas: days_until_due: 'if(due, ((date(due) - today()) / 86400000).round(0), "")' is_overdue: 'if(due, date(due) < today() && status != "done", false)' priority_label: 'if(priority == 1, "🔴 High", if(priority == 2, "🟡 Medium", "🟢 Low"))'

properties: status: displayName: Status formula.days_until_due: displayName: "Days Until Due" formula.priority_label: displayName: Priority

views:

• type: table name: "Active Tasks" filters: and: - 'status != "done"' order:

  • file.name
  • status
  • formula.priority_label
  • due
  • formula.days_until_due groupBy: property: status direction: ASC summaries: formula.days_until_due: Average

• type: table name: "Completed" filters: and: - 'status == "done"' order:

  • file.name
  • completed_date

Reading List Base

filters: or: - file.hasTag("book") - file.hasTag("article")

formulas: reading_time: 'if(pages, (pages * 2).toString() + " min", "")' status_icon: 'if(status == "reading", "📖", if(status == "done", "✅", "📚"))' year_read: 'if(finished_date, date(finished_date).year, "")'

properties: author: displayName: Author formula.status_icon: displayName: "" formula.reading_time: displayName: "Est. Time"

views:

• type: cards name: "Library" order:

  • cover
  • file.name
  • author
  • formula.status_icon filters: not:
    • 'status == "dropped"'

• type: table name: "Reading List" filters: and: - 'status == "to-read"' order:

  • file.name
  • author
  • pages
  • formula.reading_time

Project Notes Base

filters: and: - file.inFolder("Projects") - 'file.ext == "md"'

formulas: last_updated: 'file.mtime.relative()' link_count: 'file.links.length'

summaries: avgLinks: 'values.filter(value.isType("number")).mean().round(1)'

properties: formula.last_updated: displayName: "Updated" formula.link_count: displayName: "Links"

views:

• type: table name: "All Projects" order:

  • file.name
  • status
  • formula.last_updated
  • formula.link_count summaries: formula.link_count: avgLinks groupBy: property: status direction: ASC

• type: list name: "Quick List" order:

  • file.name
  • status

Daily Notes Index

filters: and: - file.inFolder("Daily Notes") - '/^\d{4}-\d{2}-\d{2}$/.matches(file.basename)'

formulas: word_estimate: '(file.size / 5).round(0)' day_of_week: 'date(file.basename).format("dddd")'

properties: formula.day_of_week: displayName: "Day" formula.word_estimate: displayName: "~Words"

views:

• type: table name: "Recent Notes" limit: 30 order:
  • file.name
  • formula.day_of_week
  • formula.word_estimate
  • file.mtime

Embedding Bases

Embed in Markdown files:

![[MyBase.base]]

<!-- Specific view --> ![[MyBase.base#View Name]]

YAML Quoting Rules

• Use single quotes for formulas containing double quotes: 'if(done, "Yes", "No")'

• Use double quotes for simple strings: "My View Name"

• Escape nested quotes properly in complex expressions

Common Patterns

Filter by Tag

filters: and: - file.hasTag("project")

Filter by Folder

filters: and: - file.inFolder("Notes")

Filter by Date Range

filters: and: - 'file.mtime > now() - "7d"'

Filter by Property Value

filters: and: - 'status == "active"' - 'priority >= 3'

Combine Multiple Conditions

filters: or: - and: - file.hasTag("important") - 'status != "done"' - and: - 'priority == 1' - 'due != ""'

References

• Bases Syntax

• Functions

• Views

• Formulas