/obsidian-bases

name: obsidian-bases
description: Explain, draft, and validate Obsidian Bases .base files with filters, formulas, properties, summaries, and table, card, list, or version-gated kanban 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](https://help.obsidian.md/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](../wiki/references/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. Record static validation separately from native Obsidian rendering. Follow [the conformance procedure](../../docs/native-conformance.md) when application behavior cannot be verified locally. Never label unobserved output as tested.

Version boundary

Checked 2026-10-17 against [official view documentation](https://obsidian.md/help/bases/views). Table and cards require 1.9+, list requires 1.10+, and native kanban requires 1.14+. Map requires the Maps plugin. These are documented minimum versions, not versions exercised by this package's offline tests. On an older app, keep an ordinary table fallback. Preserve unknown existing view fields.

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:
  status_label: 'if(status == "mature", "Ready", "Review")'

properties:
  status:
    displayName: "Status"

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

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()`.
• Date subtraction has conflicting current source descriptions. Treat the

examples in the date section below as unverified compatibility candidates, and test the user's supported app versions before relying on the output.

• 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.

Date arithmetic needs native evidence

The [Help syntax](https://obsidian.md/help/bases/syntax) checked 2026-10-17 still describes date differences in milliseconds. The official [1.9.3 changelog](https://obsidian.md/changelog/2025-06-26-desktop-v1.9.3/) describes a Duration, and the pinned upstream skill also uses a Duration field. The recorded excerpts of the [API types at the reviewed commit](https://github.com/obsidianmd/obsidian-api/blob/9abd9605ce081383674aae1ed111c456edde0688/obsidian.d.ts) do not include a Duration definition, so they are not cited for either reading. No native app observation in this update resolves that disagreement.

These retained millisecond expressions are candidates for an isolated test, not a compatibility guarantee:

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

Compare direct subtraction/division, the Duration day field, and explicit `number(date)` subtraction using one-day, multi-month, negative, and missing values. Record app version, timezone, expression, actual value/type, and errors using [native-conformance.md](../../docs/native-conformance.md). Do not rewrite existing formulas or assert that any candidate is correct before that check.

Additional views

Cards and list examples:

views:
  - type: cards