---

name: obsidian-bases description: Explain, draft, and validate Obsidian Bases .base files with filters, formulas, properties, summaries, and table, card, or list views. Use for Obsidian Bases, database-like vault views, dynamic tables, reading lists, task trackers, filters, formulas, summaries, and .base file edits.

Obsidian Bases

Use this as a compact workflow and fallback syntax reference. Prefer a separately installed kepano/obsidian-skills obsidian-bases skill, then the current official Bases syntax, for detailed or version-sensitive fields and functions.

Answer design and syntax questions read-only. For a requested .base edit, resolve the user vault and use one inspected transaction; never write the file directly.

Resolve the installed product root from this skill's own location, not from the vault or current working directory:

PRODUCT_ROOT=/absolute/path/to/installed/claude-obsidian
CORE="$PRODUCT_ROOT/scripts/claude-obsidian.py"
test -f "$CORE"

Every ../wiki/references/ link in this file resolves the same way, relative to this skill's own directory under $PRODUCT_ROOT, never relative to the selected vault's wiki/ directory.

Workflow

1. Inspect representative note properties and any existing .base file.

2. Define the smallest filter that selects the intended notes.

3. Add formulas only for values that must be computed.

4. Choose views and display order. Do not assume a view type or option is supported by the user's Obsidian version or installed plugins.

5. Validate YAML, expression quoting, property names, formula references, and null handling.

6. Preview the complete file and expected result set before a mutation.

7. If an edit was requested, read operation-transactions.md, keep the .base file under wiki/, and build one claude-obsidian.transaction.v1 bundle with operation_type: base. Inspect it, then set APPROVAL_SHA256 to the returned approval_sha256 only after review and apply once:

   python3 "$CORE" transaction inspect "$BUNDLE" --vault "$VAULT"
   python3 "$CORE" transaction apply "$BUNDLE" --vault "$VAULT" \
     --approved-plan-sha256 "$APPROVAL_SHA256"
   

8. Ask the user to render the Base in Obsidian when application-level behavior cannot be verified locally.

Compact schema

.base files are YAML. Common top-level keys are filters, formulas, properties, summaries, and views.

filters:
  and:
    - file.inFolder("wiki")
    - 'status != "archived"'

formulas:
  age_days: '((now() - file.ctime) / 86400000).round(0)'
  status_label: 'if(status == "mature", "Ready", "Review")'

properties:
  status:
    displayName: "Status"
  formula.age_days:
    displayName: "Age (days)"

views:
  - type: table
    name: "Wiki pages"
    order:
      - file.name
      - type
      - status
      - updated
      - formula.age_days

Global filters apply to every view. A view may also define its own filters. Recursive filter objects use one of and, or, or not at each level.

filters:
  or:
    - file.hasTag("concept")
    - and:
        - file.hasTag("source")
        - 'status == "active"'

Use note properties by name, file metadata as file.name, file.path, file.folder, file.ext, file.ctime, file.mtime, or file.tags, and computed properties as formula.<name>.

Formula and YAML rules

• Quote expressions that contain operators, colons, or nested string quotes.
• Guard nullable properties with if().
• Subtracting two dates returns a millisecond number. Divide by 86400000 before rounding when a whole-day count is intended.
• Define every formula.<name> before referencing it in a view or property display configuration.
• Do not transplant Dataview-only keys such as from or where into a Base.
• Do not invent properties absent from the selected notes without explaining that the resulting column will be empty.

formulas:
  days_until: 'if(due_date, ((date(due_date) - today()) / 86400000).round(0), "")'

Table, cards, and list views are common:

views:
  - type: cards
    name: "Reading list"
    order:
      - file.name
      - author
      - status
  - type: list
    name: "Quick list"
    order:
      - file.name
      - status

Embed a Base or one named view in a Markdown note:

![[Dashboard.base]]
![[Dashboard.base#Wiki pages]]

After an applied edit, report the operation ID, exact changed path, validation performed, and anything that still requires rendering in Obsidian. Do not commit Git.