Obsidian Bases

Obsidian Bases Skill

Workflow

1. Create the file: Create a .base file in the vault with valid YAML content
2. Define scope: Add filters to select which notes appear (by tag, folder, property, or date)
3. Add formulas (optional): Define computed properties in the formulas section
4. Configure views: Add one or more views (table, cards, list, or map) with order specifying which properties to display
5. Validate: Verify the file is valid YAML with no syntax errors. Check that all referenced properties and formulas exist. Common issues: unquoted strings containing special YAML characters, mismatched quotes in formula expressions, referencing formula.X without defining X in formulas
6. Test in Obsidian: Open the .base file in Obsidian to confirm the view renders correctly. If it shows a YAML error, check quoting rules below

Schema

Base files use the .base extension and contain valid YAML.

# 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 | | = | greater than or equal | | `, =, !, %, @, `` must be quoted.

# WRONG - colon in unquoted string
displayName: Status: Active

# CORRECT
displayName: "Status: Active"

Mismatched quotes in formulas: When a formula contains double quotes, wrap the entire formula in single quotes.

# WRONG - double quotes inside double quotes
formulas:
  label: "if(done, "Yes", "No")"

# CORRECT - single quotes wrapping double quotes
formulas:
  label: 'if(done, "Yes", "No")'

Common Formula Errors

Duration math without field access: Subtracting dates returns a Duration, not a number. Always access .days, .hours, etc.

# WRONG - Duration is not a number
"(now() - file.ctime).round(0)"

# CORRECT - access .days first, then round
"(now() - file.ctime).days.round(0)"

Missing null checks: Properties may not exist on all notes. Use if() to guard.

# WRONG - crashes if due_date is empty
"(date(due_date) - today()).days"

# CORRECT - guard with if()
'if(due_date, (date(due_date) - today()).days, "")'

Referencing undefined formulas: Ensure every formula.X in order or properties has a matching entry in formulas.

# This will fail silently if 'total' is not defined in formulas
order:
  - formula.total

# Fix: define it
formulas:
  total: "price * quantity"

Boundaries — interaction with @obsidian-brain

The brain/ subtree of any project vault is a closed graph owned by @obsidian-brain. Bases must not breach its isolation.

• Never include wikilinks ([[...]]) or embeds (![[...]]) — in the base file body, in any view's name, in formula string literals, or anywhere else — that target files under brain/ (sessions, topics, decisions, or the -brain.md index file). The brain/ subtree is owned and maintained by @obsidian-brain; bases must not surface its contents through wikilinks or embeds in either direction.
• Never embed a .base file inside any note under brain/, and never embed a brain note (or its index) inside a .base file. The ![[.base]] and ![[]] patterns are forbidden across this boundary.
• Never author a base whose global or per-view filters resolve into brain/. When a base scopes the entire vault, exclude the subtree explicitly:

```yaml filters: and:

• file.hasTag("task")
• '!file.inFolder("brain")'

```

The same applies to per-view filters that would otherwise sweep in brain notes.

• Never add formula.X expressions that resolve files inside brain/ (e.g., file("brain/-brain"), link("brain/topics/auth")). Formulas that create links to brain notes are equivalent to a wikilink and fall under the same prohibition.
• If the user asks for a base that lists sessions, decisions, or topics, redirect them to @obsidian-brain — that surface is owned there (the brain.base dashboard lives inside brain/ and is generated by @obsidian-brain, not by this skill).

References

• Bases Syntax
• Functions
• Views
• Formulas
• [Complete Functions Reference](references/FUNCTIONS_REFERENCE.md)

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Bruno-Cunha-Souza
• Source: Bruno-Cunha-Souza/ValarMindSkills
• License: MIT

Install and usage instructions live in the source repository linked above.