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](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: 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: 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 . 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. 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: 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: For Obsidian 1.14+, group a kanban by an existing writable note property: groupOrder lists visible groups in display order. An absent groupOrder shows all groups using the groupBy sort; an empty list hides every group. null includes pages without the grouped value. Adding an empty group does not create a note. Native card moves can change a note property, and grouping by file.folder can move files; agents must still use reviewed transactions for vault mutations. A formula or other read only file property is unsuitable for an editable status board. See [Kanban view](https://obsidian.md/help/bases/views/kanban). Embed a Base or one named view in a Markdown note: 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.

obsidian-bases