obsidian-bases

name	obsidian-bases
description	Create and edit .base database views, filters, and formulas.
platforms	["linux","macos","windows"]
version	1.1.0
author	Harish Kukreja (counterposition), Hermes Agent (adapted from Steph Ango's official Obsidian skills)
license	MIT
metadata	{"hermes":{"tags":["obsidian","note-taking","yaml","bases","database-views"],"related_skills":["obsidian","obsidian-markdown","obsidian-cli","json-canvas"]}}

Obsidian Bases Skill

Create and edit Obsidian Bases: YAML .base files that render database-like views (tables, cards, lists, maps) over the notes in a vault, with filters, computed formula properties, and summaries. Adapted from Steph Ango's MIT-licensed official Obsidian skills.

When to Use

• Creating or editing .base files
• The user mentions Bases, table/card views over notes, filters, formulas, or summaries in Obsidian

Route elsewhere for broad vault work (obsidian), regular note authoring (obsidian-markdown), .canvas files (json-canvas), or driving the running app (obsidian-cli).

Prerequisites

None — .base files are plain YAML and no running Obsidian app is required (only Obsidian can render the views). Resolve the vault path first (see the obsidian skill).

How to Run

Read .base files with read_file, create them with write_file, and make focused edits with patch. Find existing bases with search_files using pattern: "*.base" and target: "files".

Quick Reference

Schema

# Global filters apply to ALL views in the base.
# A filter is either a single expression string, or an object with
# exactly ONE key (and / or / not) whose list items are themselves filters.
filters:
  and:
    - 'status == "active"'
    - not:
        - 'file.hasTag("archived")'

# Formula properties computed for every note, usable in all views
formulas:
  formula_name: 'expression'

# Display names and settings for properties
properties:
  property_name:
    displayName: "Display Name"
  formula.formula_name:
    displayName: "Formula Display Name"

# Custom summary formulas
summaries:
  custom_summary_name: 'values.mean().round(3)'

# One or more views
views:
  - type: table            # table | cards | list | map
    name: "View Name"
    limit: 10              # optional
    groupBy:               # optional
      property: property_name
      direction: ASC       # ASC | DESC
    filters:               # view-specific, same rules as global filters
      and:
        - 'status == "active"'
    order:                 # properties to display, in order
      - file.name
      - property_name
      - formula.formula_name
    summaries:             # map properties to summary formulas
      property_name: Average

Filters

Expressions compare properties with ==, !=, >, <, >=, <= and combine with &&, ||, !. Common predicates: file.hasTag("x"), file.hasLink("Note"), file.inFolder("Folder"). Nest by making a list item an and/or/not object.

Properties

1. Note properties — frontmatter values: note.author or just author
2. File properties — metadata: file.name, file.basename, file.path, file.folder, file.ext, file.size, file.ctime, file.mtime, file.tags, file.links, file.backlinks, file.embeds
3. Formula properties — computed values: formula.my_formula

this refers to the base file itself in the main content area, to the embedding file when embedded, and to the active file in the sidebar.

Formulas

formulas:
  total: "price * quantity"
  status_icon: 'if(done, "✅", "⏳")'
  created: 'file.ctime.format("YYYY-MM-DD")'
  days_old: '((now() - file.ctime) / 86400000).round(0)'
  days_until_due: 'if(due_date, ((date(due_date) - today()) / 86400000).round(0), "")'

Key functions: date(), now(), today(), if(condition, then, else?), duration(), file(), link(). The function reference for all types (Date, String, Number, List, File, Link, Object, RegExp) is in FUNCTIONS_REFERENCE.md.

Subtracting two dates yields the difference in milliseconds — divide by 86400000 to get days (see days_old above). Add or subtract durations with strings: now() + "1 day", today() + "7d"; duration() is only needed for arithmetic on parsed durations themselves.

Views and summaries

View types: table, cards, list, and map (map needs lat/long properties and the Maps community plugin). Built-in summary formulas include Average, Min, Max, Sum, Median, Stddev, Earliest, Latest, Checked, Empty, Filled, Unique. Worked examples (task tracker, reading list, daily-notes index) are in EXAMPLES.md.

Embedding

![[MyBase.base]]              Embed base in a note
![[MyBase.base#View Name]]    Embed a specific view

Procedure

1. Create the .base file in the vault with write_file.
2. Define scope with global filters (tag, folder, property, or date).
3. Add computed properties in formulas as needed.
4. Configure one or more views, each with order listing the properties to display; add groupBy, view filters, and summaries as needed.
5. Validate YAML syntax and references (see Verification).
6. If a running Obsidian instance is available, open the file to confirm the view renders (the obsidian-cli skill can do this).

Pitfalls

• Quoting: wrap formulas containing double quotes in single quotes: 'if(done, "Yes", "No")'. Quote any YAML string containing :, #, [, {, or other special characters.
• Filter objects take exactly one key — and, or, or not. Do not put several of them at the same level of the same object; nest instead.
• Date subtraction returns milliseconds, not days: divide by 86400000 before rounding — '((date(due) - today()) / 86400000).round(0)'.
• Missing null guards: properties may be absent on some notes. Guard with if(): 'if(due, ((date(due) - today()) / 86400000).round(0), "")'.
• Undefined formula references: every formula.X used in order, properties, or summaries must be defined under formulas — unknown references fail silently in Obsidian.

Verification

Parse the file to confirm it is valid YAML (via terminal: python -c 'import yaml, sys; yaml.safe_load(open(sys.argv[1]))' file.base). Then re-read it with read_file and check: each filter object has exactly one of and/or/not; every formula.X reference is defined; every view has a type (and a distinct name when there are multiple views). Finally, open it in Obsidian if available — a YAML error banner means a quoting problem (see Pitfalls).

References

• Worked examples: references/EXAMPLES.md
• Full function reference: references/FUNCTIONS_REFERENCE.md
• Bases Syntax · Functions · Views
• Source: kepano/obsidian-skills by Steph Ango, MIT — full license in THIRD_PARTY_NOTICES.md