Obsidian bases

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

OperatorDescription==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

1. Note properties - From frontmatter: note.author or just author
2. File properties - File metadata: file.name, file.mtime, etc.
3. Formula properties - Computed values: formula.my_formula

File Properties Reference

PropertyTypeDescriptionfile.nameStringFile namefile.basenameStringFile name without extensionfile.pathStringFull path to filefile.folderStringParent folder pathfile.extStringFile extensionfile.sizeNumberFile size in bytesfile.ctimeDateCreated timefile.mtimeDateModified timefile.tagsListAll tags in filefile.linksListInternal links in filefile.backlinksListFiles linking to this filefile.embedsListEmbeds in the notefile.propertiesObjectAll 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")'

  # Calculate days since created (use .days for Duration)
  days_old: '(now() - file.ctime).days'

  # Calculate days until due date
  days_until_due: 'if(due_date, (date(due_date) - today()).days, "")'

Functions Reference

Global Functions

FunctionSignatureDescriptiondate()date(string): dateParse string to date. Format: YYYY-MM-DD HH:mm:ssduration()duration(string): durationParse duration stringnow()now(): dateCurrent date and timetoday()today(): dateCurrent date (time = 00:00:00)if()if(condition, trueResult, falseResult?)Conditionalmin()min(n1, n2, ...): numberSmallest numbermax()max(n1, n2, ...): numberLargest numbernumber()number(any): numberConvert to numberlink()link(path, display?): LinkCreate a linklist()list(element): ListWrap in list if not alreadyfile()file(path): fileGet file objectimage()image(path): imageCreate image for renderingicon()icon(name): iconLucide icon by namehtml()html(string): htmlRender as HTMLescapeHTML()escapeHTML(string): stringEscape HTML characters

Any Type Functions

FunctionSignatureDescriptionisTruthy()any.isTruthy(): booleanCoerce to booleanisType()any.isType(type): booleanCheck typetoString()any.toString(): stringConvert to string

Date Functions & Fields

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

FunctionSignatureDescriptiondate()date.date(): dateRemove time portionformat()date.format(string): stringFormat with Moment.js patterntime()date.time(): stringGet time as stringrelative()date.relative(): stringHuman-readable relative timeisEmpty()date.isEmpty(): booleanAlways false for dates

Duration Type

When subtracting two dates, the result is a Duration type (not a number). Duration has its own properties and methods.

Duration Fields:

FieldTypeDescriptionduration.daysNumberTotal days in durationduration.hoursNumberTotal hours in durationduration.minutesNumberTotal minutes in durationduration.secondsNumberTotal seconds in durationduration.millisecondsNumberTotal milliseconds in duration

IMPORTANT: Duration does NOT support .round(), .floor(), .ceil() directly. You must access a numeric field first (like .days), then apply number functions.

# CORRECT: Calculate days between dates
"(date(due_date) - today()).days"                    # Returns number of days
"(now() - file.ctime).days"                          # Days since created

# CORRECT: Round the numeric result if needed
"(date(due_date) - today()).days.round(0)"           # Rounded days
"(now() - file.ctime).hours.round(0)"                # Rounded hours

# WRONG - will cause error:
# "((date(due) - today()) / 86400000).round(0)"      # Duration doesn't support division then round

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 returns Duration type
"now() - file.ctime"                    # Returns Duration
"(now() - file.ctime).days"             # Get days as number
"(now() - file.ctime).hours"            # Get hours as number

# Complex duration arithmetic
"now() + (duration('1d') * 2)"

String Functions

Field: string.length

FunctionSignatureDescriptioncontains()string.contains(value): booleanCheck substringcontainsAll()string.containsAll(...values): booleanAll substrings presentcontainsAny()string.containsAny(...values): booleanAny substring presentstartsWith()string.startsWith(query): booleanStarts with queryendsWith()string.endsWith(query): booleanEnds with queryisEmpty()string.isEmpty(): booleanEmpty or not presentlower()string.lower(): stringTo lowercasetitle()string.title(): stringTo Title Casetrim()string.trim(): stringRemove whitespacereplace()string.replace(pattern, replacement): stringReplace patternrepeat()string.repeat(count): stringRepeat stringreverse()string.reverse(): stringReverse stringslice()string.slice(start, end?): stringSubstringsplit()string.split(separator, n?): listSplit to list

Number Functions

FunctionSignatureDescriptionabs()number.abs(): numberAbsolute valueceil()number.ceil(): numberRound upfloor()number.floor(): numberRound downround()number.round(digits?): numberRound to digitstoFixed()number.toFixed(precision): stringFixed-point notationisEmpty()number.isEmpty(): booleanNot present

List Functions

Field: list.length

FunctionSignatureDescriptioncontains()list.contains(value): booleanElement existscontainsAll()list.containsAll(...values): booleanAll elements existcontainsAny()list.containsAny(...values): booleanAny element existsfilter()list.filter(expression): listFilter by condition (uses value, index)map()list.map(expression): listTransform elements (uses value, index)reduce()list.reduce(expression, initial): anyReduce to single value (uses value, index, acc)flat()list.flat(): listFlatten nested listsjoin()list.join(separator): stringJoin to stringreverse()list.reverse(): listReverse orderslice()list.slice(start, end?): listSublistsort()list.sort(): listSort ascendingunique()list.unique(): listRemove duplicatesisEmpty()list.isEmpty(): booleanNo elements

File Functions

FunctionSignatureDescriptionasLink()file.asLink(display?): LinkConvert to linkhasLink()file.hasLink(otherFile): booleanHas link to filehasTag()file.hasTag(...tags): booleanHas any of the tagshasProperty()file.hasProperty(name): booleanHas propertyinFolder()file.inFolder(folder): booleanIn folder or subfolder

Link Functions

FunctionSignatureDescriptionasFile()link.asFile(): fileGet file objectlinksTo()link.linksTo(file): booleanLinks to file

Object Functions

FunctionSignatureDescriptionisEmpty()object.isEmpty(): booleanNo propertieskeys()object.keys(): listList of keysvalues()object.values(): listList of values

Regular Expression Functions

FunctionSignatureDescriptionmatches()regexp.matches(string): booleanTest 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

NameInput TypeDescriptionAverageNumberMathematical meanMinNumberSmallest numberMaxNumberLargest numberSumNumberSum of all numbersRangeNumberMax - MinMedianNumberMathematical medianStddevNumberStandard deviationEarliestDateEarliest dateLatestDateLatest dateRangeDateLatest - EarliestCheckedBooleanCount of true valuesUncheckedBooleanCount of false valuesEmptyAnyCount of empty valuesFilledAnyCount of non-empty valuesUniqueAnyCount 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()).days, "")'
  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