# Operations > Every operation of the HTTP API, offered to agents as an MCP tool of the same name, grouped by kind. The engine has 54 operations of five kinds, like the statements of a SQL reference. The MCP server, `datanotes mcp`, offers each operation as an MCP tool of the same name, and `engineTools()` of `datanotes/mcp` gives the same definitions to [your own MCP server](https://datanotes.dev/develop/build-on-datanotes/#build-your-own-mcp-server). `DatanotesClient.call(name, args)` runs one from code. Over HTTP each one is `POST /datanotes/operations//`, with its arguments as the JSON body: the [HTTP API reference](https://datanotes.dev/api/) lists them. Next to them, `datanotes mcp` offers three tools that read these docs offline, `list_docs`, `read_docs` and `search_docs`; they aren’t operations of the engine ([Read the docs offline](https://datanotes.dev/guides/agents/docs-offline/)). `search_docs` takes required and excluded words, and becomes a hybrid search when the engine has semantic search on ([Search by words and by meaning](https://datanotes.dev/guides/agents/docs-offline/#search-by-words-and-by-meaning)). ## Schema (DDL) Operations that define the database: tables, columns, constraints, bases and views. [Schema operations (DDL)](https://datanotes.dev/reference/operations/schema/) lists their parameters. | Operation | What it does | Examples | | ------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [`create_table`](https://datanotes.dev/reference/operations/schema/#create_table) | Create a table: `name`, in `catalog` and `schema` (default: the database’s defaults); the definition goes in metastore.yaml, the rows in `////`. | [Catalogs, schemas and the database](https://datanotes.dev/guides/database-objects/catalogs-and-schemas/), [Tables](https://datanotes.dev/guides/database-objects/tables/), [Columns and types](https://datanotes.dev/guides/database-objects/columns/), [Bases](https://datanotes.dev/guides/database-objects/bases/), [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/), [Write and move rows](https://datanotes.dev/guides/read-and-write/write-rows/), [Automatic links](https://datanotes.dev/guides/read-and-write/automatic-links/), [Import existing notes](https://datanotes.dev/guides/read-and-write/import-notes/), [Table history and time travel](https://datanotes.dev/guides/history/table-history/) | | [`drop_table`](https://datanotes.dev/reference/operations/schema/#drop_table) | Drop a table. | [Tables](https://datanotes.dev/guides/database-objects/tables/) | | [`alter_table`](https://datanotes.dev/reference/operations/schema/#alter_table) | Alter a table: move it (`catalog`, `schema`), rename it (`name`), change `partition` / `filename` patterns, `description` (changes, never goes: “” is refused), `aliases`, `exclude` folders, `row_template` (“” removes it), `history` (true \| false \| “default”), `autolink_target` (true \| false \| “default”: may automatic links link its rows? default: yes, unless its rows are named by a date or a time) or `tags` (key/value labels merged into the table’s, e.g. | [Catalogs, schemas and the database](https://datanotes.dev/guides/database-objects/catalogs-and-schemas/), [Tables](https://datanotes.dev/guides/database-objects/tables/), [Automatic links](https://datanotes.dev/guides/read-and-write/automatic-links/), [Import existing notes](https://datanotes.dev/guides/read-and-write/import-notes/), [Table history and time travel](https://datanotes.dev/guides/history/table-history/) | | [`clone_table`](https://datanotes.dev/reference/operations/schema/#clone_table) | CREATE TABLE `target` CLONE `source`: same definition plus independent copies of its rows (deep clone), optionally as of a `version` / `timestamp`. | [Tables](https://datanotes.dev/guides/database-objects/tables/), [Bases](https://datanotes.dev/guides/database-objects/bases/), [Table history and time travel](https://datanotes.dev/guides/history/table-history/) | | [`add_column`](https://datanotes.dev/reference/operations/schema/#add_column) | Add a typed column. | [Columns and types](https://datanotes.dev/guides/database-objects/columns/), [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/), [Import existing notes](https://datanotes.dev/guides/read-and-write/import-notes/) | | [`rename_column`](https://datanotes.dev/reference/operations/schema/#rename_column) | Rename a column in metastore.yaml and on every row. | [Columns and types](https://datanotes.dev/guides/database-objects/columns/) | | [`drop_column`](https://datanotes.dev/reference/operations/schema/#drop_column) | Remove a column from the schema and every row. | [Columns and types](https://datanotes.dev/guides/database-objects/columns/) | | [`alter_column`](https://datanotes.dev/reference/operations/schema/#alter_column) | Change a column’s attributes (type, min/max/step, values, required, default, label, aliases, description, note, `ref_where`, `ref_by` (see list_link_targets); `null` removes an attribute, except `description`, which changes but never goes (null or “” is refused); `dense` true/false). | [Tables](https://datanotes.dev/guides/database-objects/tables/), [Columns and types](https://datanotes.dev/guides/database-objects/columns/), [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/) | | [`rename_value`](https://datanotes.dev/reference/operations/schema/#rename_value) | Rename one value of an enum column (e.g. | [Columns and types](https://datanotes.dev/guides/database-objects/columns/) | | [`comment_on`](https://datanotes.dev/reference/operations/schema/#comment_on) | COMMENT ON CATALOG / SCHEMA: set the `description` of a catalog (`catalog` alone) or of one of its schemas (`catalog` and `schema`) in metastore.yaml: what it holds, so agents pick the right place. | [Catalogs, schemas and the database](https://datanotes.dev/guides/database-objects/catalogs-and-schemas/) | | [`define_base`](https://datanotes.dev/reference/operations/schema/#define_base) | Create or replace a base: a named set of columns (same spec as `create_table`) that tables inherit, like a parent class (`bases` in `metastore.yaml`). | [Bases](https://datanotes.dev/guides/database-objects/bases/) | | [`set_table_bases`](https://datanotes.dev/reference/operations/schema/#set_table_bases) | Set the bases a table inherits from (`bases`, in order; `[]` removes them). | [Bases](https://datanotes.dev/guides/database-objects/bases/) | | [`add_constraint`](https://datanotes.dev/reference/operations/schema/#add_constraint) | ALTER TABLE ADD CONSTRAINT `name` CHECK: `check` is a where filter every row must match, e.g. | [CHECK constraints](https://datanotes.dev/guides/data-quality/check-constraints/) | | [`drop_constraint`](https://datanotes.dev/reference/operations/schema/#drop_constraint) | Remove the CHECK constraint `name` from `table`. | [CHECK constraints](https://datanotes.dev/guides/data-quality/check-constraints/) | | [`create_view`](https://datanotes.dev/reference/operations/schema/#create_view) | Create (or `replace`) a view: a named select stored in metastore.yaml. | [Views](https://datanotes.dev/guides/database-objects/views/) | | [`drop_view`](https://datanotes.dev/reference/operations/schema/#drop_view) | Remove a view from `metastore.yaml` (undo with `undo_migration`). | [Views](https://datanotes.dev/guides/database-objects/views/) | ## Rows (DML) Operations that write rows: insert, update, merge, delete, move, adopt and batch. [Row operations (DML)](https://datanotes.dev/reference/operations/rows/) lists their parameters. | Operation | What it does | Examples | | -------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [`insert_row`](https://datanotes.dev/reference/operations/rows/#insert_row) | Insert a row (new note). | [Catalogs, schemas and the database](https://datanotes.dev/guides/database-objects/catalogs-and-schemas/), [Tables](https://datanotes.dev/guides/database-objects/tables/), [Columns and types](https://datanotes.dev/guides/database-objects/columns/), [Bases](https://datanotes.dev/guides/database-objects/bases/), [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/), [Validation](https://datanotes.dev/guides/data-quality/validation/), [CHECK constraints](https://datanotes.dev/guides/data-quality/check-constraints/), [Write and move rows](https://datanotes.dev/guides/read-and-write/write-rows/), [Automatic links](https://datanotes.dev/guides/read-and-write/automatic-links/), [Batch writes](https://datanotes.dev/guides/read-and-write/batch/), [Import existing notes](https://datanotes.dev/guides/read-and-write/import-notes/), [Journal and undo](https://datanotes.dev/guides/history/journal-and-undo/), [Table history and time travel](https://datanotes.dev/guides/history/table-history/), [Change data feed](https://datanotes.dev/guides/history/change-data-feed/), [Restore a table or the database](https://datanotes.dev/guides/history/restore/) | | [`update_row`](https://datanotes.dev/reference/operations/rows/#update_row) | Update exactly ONE row, addressed by its `id` (the system UUID) or its `path`; refused when the row does not exist (or id and path disagree). | [Columns and types](https://datanotes.dev/guides/database-objects/columns/), [Bases](https://datanotes.dev/guides/database-objects/bases/), [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/), [CHECK constraints](https://datanotes.dev/guides/data-quality/check-constraints/), [Hand edits](https://datanotes.dev/guides/data-quality/hand-edits/), [Write and move rows](https://datanotes.dev/guides/read-and-write/write-rows/), [Automatic links](https://datanotes.dev/guides/read-and-write/automatic-links/), [Batch writes](https://datanotes.dev/guides/read-and-write/batch/), [Journal and undo](https://datanotes.dev/guides/history/journal-and-undo/), [Table history and time travel](https://datanotes.dev/guides/history/table-history/), [Change data feed](https://datanotes.dev/guides/history/change-data-feed/), [Restore a table or the database](https://datanotes.dev/guides/history/restore/) | | [`update_rows`](https://datanotes.dev/reference/operations/rows/#update_rows) | Update every row matching `where` (required: `{}` is every row). | [Write and move rows](https://datanotes.dev/guides/read-and-write/write-rows/) | | [`merge_rows`](https://datanotes.dev/reference/operations/rows/#merge_rows) | MERGE (upsert) `rows` into `table` by the key columns `on` (e.g. | [Write and move rows](https://datanotes.dev/guides/read-and-write/write-rows/) | | [`delete_rows`](https://datanotes.dev/reference/operations/rows/#delete_rows) | Delete rows matching `where`. | [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/), [Write and move rows](https://datanotes.dev/guides/read-and-write/write-rows/), [Table history and time travel](https://datanotes.dev/guides/history/table-history/) | | [`move_rows`](https://datanotes.dev/reference/operations/rows/#move_rows) | Move rows matching `where` (required: `{}` is every row) to another table (e.g. | [Write and move rows](https://datanotes.dev/guides/read-and-write/write-rows/) | | [`adopt_rows`](https://datanotes.dev/reference/operations/rows/#adopt_rows) | Turn existing notes (not rows of any table yet) into rows of `table`, keeping their body and links: `rename` keys (`{"data": "occurred_at"}`), `set` for all, `per_row` values by note path (`{"Home/x.md": {"zone": "[[Kitchen]]"}}`), `drop` keys the table does not have. | [Import existing notes](https://datanotes.dev/guides/read-and-write/import-notes/) | | [`batch`](https://datanotes.dev/reference/operations/rows/#batch) | Several writes that succeed or fail together. | [Views](https://datanotes.dev/guides/database-objects/views/), [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/), [CHECK constraints](https://datanotes.dev/guides/data-quality/check-constraints/), [Batch writes](https://datanotes.dev/guides/read-and-write/batch/), [Restore a table or the database](https://datanotes.dev/guides/history/restore/) | | [`align_relations`](https://datanotes.dev/reference/operations/rows/#align_relations) | Add the reciprocal links missing on a table’s `inverse` link columns (e.g. | [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/) | | [`recompute_columns`](https://datanotes.dev/reference/operations/rows/#recompute_columns) | Bring generated and identity columns up to date (all rows, or only `paths`), e.g. | [Hand edits](https://datanotes.dev/guides/data-quality/hand-edits/) | ## Queries Operations that read rows and notes: select_rows, link targets, text and semantic search, the link graph. [Query operations](https://datanotes.dev/reference/operations/queries/) lists their parameters. | Operation | What it does | Examples | | ----------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [`select_rows`](https://datanotes.dev/reference/operations/queries/#select_rows) | Query rows: `{table, total, rows: [{path, ...}]}`. | [Catalogs, schemas and the database](https://datanotes.dev/guides/database-objects/catalogs-and-schemas/), [Tables](https://datanotes.dev/guides/database-objects/tables/), [Columns and types](https://datanotes.dev/guides/database-objects/columns/), [Views](https://datanotes.dev/guides/database-objects/views/), [Bases](https://datanotes.dev/guides/database-objects/bases/), [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/), [Validation](https://datanotes.dev/guides/data-quality/validation/), [CHECK constraints](https://datanotes.dev/guides/data-quality/check-constraints/), [Hand edits](https://datanotes.dev/guides/data-quality/hand-edits/), [Read and filter rows](https://datanotes.dev/guides/read-and-write/read-and-filter/), [Joins and aggregates](https://datanotes.dev/guides/read-and-write/joins-and-aggregates/), [Write and move rows](https://datanotes.dev/guides/read-and-write/write-rows/), [Batch writes](https://datanotes.dev/guides/read-and-write/batch/), [Import existing notes](https://datanotes.dev/guides/read-and-write/import-notes/), [Journal and undo](https://datanotes.dev/guides/history/journal-and-undo/), [Table history and time travel](https://datanotes.dev/guides/history/table-history/), [Restore a table or the database](https://datanotes.dev/guides/history/restore/) | | [`list_link_targets`](https://datanotes.dev/reference/operations/queries/#list_link_targets) | The rows a link column may point to, for one row: what an agent or a picker offers before writing the link. | [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/) | | [`read_note`](https://datanotes.dev/reference/operations/queries/#read_note) | Read a note or another file of the vault: `{path, content, front_matter, tags, modified_at, created_at, size}`. | [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/), [Hand edits](https://datanotes.dev/guides/data-quality/hand-edits/), [Import existing notes](https://datanotes.dev/guides/read-and-write/import-notes/), [Read and search notes](https://datanotes.dev/guides/search/text/) | | [`list_folder`](https://datanotes.dev/reference/operations/queries/#list_folder) | The direct children of a vault folder: `{folder, folders, files}`, each a vault path, sorted; dot-files and dot-folders are left out. | [Catalogs, schemas and the database](https://datanotes.dev/guides/database-objects/catalogs-and-schemas/), [Tables](https://datanotes.dev/guides/database-objects/tables/), [Columns and types](https://datanotes.dev/guides/database-objects/columns/), [Write and move rows](https://datanotes.dev/guides/read-and-write/write-rows/), [Read and search notes](https://datanotes.dev/guides/search/text/) | | [`search_notes`](https://datanotes.dev/reference/operations/queries/#search_notes) | Plain-text search: every word of `query` must occur, case- and accent-insensitive, in the note’s path or text; there are no operators. | [Read and search notes](https://datanotes.dev/guides/search/text/) | | [`semantic_search`](https://datanotes.dev/reference/operations/queries/#semantic_search) | Find notes by meaning, not exact words: `{query, results: [{path, score, heading, snippet, table?}]}`, one result per note (its best passage), best first. | [Find notes by meaning](https://datanotes.dev/guides/search/semantic/) | | [`graph_neighbors`](https://datanotes.dev/reference/operations/queries/#graph_neighbors) | Direct neighbours of notes: what they link to (`out`) and what links to them (`in`, backlinks), with counts per edge label. | [Walk the link graph](https://datanotes.dev/guides/search/link-graph/) | | [`graph_traverse`](https://datanotes.dev/reference/operations/queries/#graph_traverse) | Breadth-first walk over links from `from_nodes` (`{"paths": [...]}` and/or `{"table", "where"}`). | [Walk the link graph](https://datanotes.dev/guides/search/link-graph/) | | [`graph_path`](https://datanotes.dev/reference/operations/queries/#graph_path) | Shortest chain of links between two sets of notes (each `{"paths": [...]}` and/or `{"table", "where"}`): `found`, `length` and `path`: the steps (`from`, `label`, `direction`, `to`). | [Walk the link graph](https://datanotes.dev/guides/search/link-graph/) | ## History Operations on the journal, a table’s versions, the change feed and webhooks: undo, time travel, restore and vacuum. [History operations](https://datanotes.dev/reference/operations/history/) lists their parameters. | Operation | What it does | Examples | | --------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [`list_migrations`](https://datanotes.dev/reference/operations/history/#list_migrations) | The operation journal, newest first: `total` (the matching operations) and `migrations`, each with `migration_id` (for undo_migration), `op`, `summary`, `table` (when it was about one), `executed_at`, `notes_changed`, `files_changed`, `undone`, `undoes`, `files_failed`, `by` (the agent), and `members` (a batch’s operations) or `batch` (the batch of an operation). | [Hand edits](https://datanotes.dev/guides/data-quality/hand-edits/), [Journal and undo](https://datanotes.dev/guides/history/journal-and-undo/) | | [`undo_migration`](https://datanotes.dev/reference/operations/history/#undo_migration) | Revert a journaled table operation by its `migration_id`. | [Columns and types](https://datanotes.dev/guides/database-objects/columns/), [Views](https://datanotes.dev/guides/database-objects/views/), [Journal and undo](https://datanotes.dev/guides/history/journal-and-undo/), [Restore a table or the database](https://datanotes.dev/guides/history/restore/) | | [`describe_history`](https://datanotes.dev/reference/operations/history/#describe_history) | DESCRIBE HISTORY: the table’s versions, newest first — `version`, `timestamp`, `operation` (CREATE TABLE, WRITE, UPDATE, DELETE, MERGE, ALTER TABLE, ADD COLUMNS, RESTORE, UNDO, …; `EXTERNAL_EDIT` = changed outside the engine: an editor, git, sync), `operation_metrics` and `migration_id` (undo). | [Table history and time travel](https://datanotes.dev/guides/history/table-history/), [Restore a table or the database](https://datanotes.dev/guides/history/restore/) | | [`table_changes`](https://datanotes.dev/reference/operations/history/#table_changes) | Change data feed between two versions (both included, end defaults to latest): one entry per row change with its values plus `_change_type` (insert, delete, update_preimage, update_postimage, metadata), `_commit_version`, `_commit_timestamp`, `_operation`, `path`. | [Table history and time travel](https://datanotes.dev/guides/history/table-history/) | | [`restore_table`](https://datanotes.dev/reference/operations/history/#restore_table) | RESTORE TABLE to a `version` or `timestamp`: rows and definition return to that state — rows added since are deleted, changed rows get their old content, removed rows come back (a dropped table is re-created). | [Restore a table or the database](https://datanotes.dev/guides/history/restore/) | | [`restore_database`](https://datanotes.dev/reference/operations/history/#restore_database) | RESTORE DATABASE to a `timestamp` (each table as of its last version committed at or before it) or to `before_migration` (a `migration_id` or a `batch`: every table as it was just before that operation ran — to rewind an agent’s run). | [Restore a table or the database](https://datanotes.dev/guides/history/restore/) | | [`vacuum_table`](https://datanotes.dev/reference/operations/history/#vacuum_table) | Delete transaction-log history older than `retain_from_version` (default: keep only the latest version); time travel before it becomes impossible. | [Vacuum old history](https://datanotes.dev/guides/history/vacuum/) | | [`list_changes`](https://datanotes.dev/reference/operations/history/#list_changes) | Change feed across all tables: numbered row changes (`seq`), oldest first, from engine writes and from hand edits (`source: external`). | [Hand edits](https://datanotes.dev/guides/data-quality/hand-edits/), [Change data feed](https://datanotes.dev/guides/history/change-data-feed/) | | [`list_webhooks`](https://datanotes.dev/reference/operations/history/#list_webhooks) | Webhooks of the change feed: id, url, filter (tables, ops, columns, exclude_actor), `cursor` (last change delivered), `status` (ok, failing, disabled), `last_delivery`, `last_error`. | [Change data feed](https://datanotes.dev/guides/history/change-data-feed/) | | [`create_webhook`](https://datanotes.dev/reference/operations/history/#create_webhook) | Push row changes to a URL (a service that would rather be called than poll `list_changes`): batches of up to 100 events POSTed as `{webhook, events, last}`, signed with `X-Datanotes-Signature: sha256=`, retried with backoff until a 2xx. | [Change data feed](https://datanotes.dev/guides/history/change-data-feed/) | | [`delete_webhook`](https://datanotes.dev/reference/operations/history/#delete_webhook) | Stop and remove a webhook (by `id` from list_webhooks). | [Change data feed](https://datanotes.dev/guides/history/change-data-feed/) | ## Auxiliary Operations that describe and check the database, configure it and maintain its indexes. [Auxiliary operations](https://datanotes.dev/reference/operations/auxiliary/) lists their parameters. | Operation | What it does | Examples | | ------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [`list_tables`](https://datanotes.dev/reference/operations/auxiliary/#list_tables) | List every table: `name`, `catalog`, `schema`, `qualified` (`personal.metrics.mood` — use it wherever a table is expected; `metrics.mood` or `mood` also work when unambiguous), `path` and, when declared, `description`, `aliases` (other words for what it records) and `tags`. | [Tables](https://datanotes.dev/guides/database-objects/tables/), [Views](https://datanotes.dev/guides/database-objects/views/) | | [`describe_table`](https://datanotes.dev/reference/operations/auxiliary/#describe_table) | Describe a table (`catalog.schema.table` or a shorter unambiguous name): `qualified`, `name`, `catalog`, `schema`, `description`, `aliases`, `layout` (`folder`, `row_folder`: the folder pattern of new rows, `archive`), `options` (`partition`, `filename`, `archive`, `exclude`), typed `columns` with label/aliases/description and the dense flag, `untyped_fields`, `row_count`, and when set: `tags`, `bases` (the bases it inherits from, in order), `constraints` (its CHECKs, name → where), `row_template`, `history`, `autolink_target`, `fields` (their values). | [Catalogs, schemas and the database](https://datanotes.dev/guides/database-objects/catalogs-and-schemas/), [Tables](https://datanotes.dev/guides/database-objects/tables/), [Bases](https://datanotes.dev/guides/database-objects/bases/), [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/) | | [`describe_database`](https://datanotes.dev/reference/operations/auxiliary/#describe_database) | Describe the database: its folder (`root`), `metastore` (`metastore.yaml`: read it freely, but it is read-only for agents and changes only through the schema operations), configuration (default catalog and schema, row partition and file-name formats, archive folder, time zone, history, automatic links), journal folder, `bases` (shared column sets and the tables using them), `catalogs` → `schemas` → `tables` (with `row_count`, `tags`, and `unreadable_count` when some rows’ front matter cannot be read) and `views`; catalogs and schemas show their `comment` (set with `comment_on`). | [Catalogs, schemas and the database](https://datanotes.dev/guides/database-objects/catalogs-and-schemas/), [Hand edits](https://datanotes.dev/guides/data-quality/hand-edits/) | | [`configure_database`](https://datanotes.dev/reference/operations/auxiliary/#configure_database) | Configure the database (persisted in metastore.yaml `config:`): `root` (rename the database folder; links follow; revert by renaming back), `default_catalog`, `default_schema`, `default_partition` (“” = flat) and `default_filename` (date formats for new time-based tables), `archive_folder`, `timezone` (IANA; completes date-times written without offset), `history` (transaction log for every table: true in a database the engine creates, false when `config` lacks it, as in a metastore from before 3.0.0; change it only on the user’s request), `autolink` (the text a write puts in a body links the notes it mentions; on by default). | [Catalogs, schemas and the database](https://datanotes.dev/guides/database-objects/catalogs-and-schemas/), [Tables](https://datanotes.dev/guides/database-objects/tables/), [Automatic links](https://datanotes.dev/guides/read-and-write/automatic-links/), [Table history and time travel](https://datanotes.dev/guides/history/table-history/) | | [`check_table`](https://datanotes.dev/reference/operations/auxiliary/#check_table) | Validate every row against the table (required, types, ranges, enums, links, unknown columns, CHECK constraints, those that follow links included, filtered link targets (ref_where / ref_by), stale generated/identity values, missing inverse links, front matter that cannot be read: code `unreadable`, with no column, for a note whose `table` line names the table but whose YAML is broken, which every other read leaves out). | [Relations and hierarchies](https://datanotes.dev/guides/database-objects/relations/), [Hand edits](https://datanotes.dev/guides/data-quality/hand-edits/), [Find rows that break the schema](https://datanotes.dev/guides/data-quality/check-table/) | | [`infer_table`](https://datanotes.dev/reference/operations/auxiliary/#infer_table) | Read-only schema inference from notes’ front matter. | [Hand edits](https://datanotes.dev/guides/data-quality/hand-edits/), [Import existing notes](https://datanotes.dev/guides/read-and-write/import-notes/) | | [`describe_semantic_index`](https://datanotes.dev/reference/operations/auxiliary/#describe_semantic_index) | The semantic search index: `enabled`, `provider`, `model`, `files`, `passages`, `pending`, `running`, `last_sync`, `last_error`. | [Find notes by meaning](https://datanotes.dev/guides/search/semantic/) | | [`sync_semantic_index`](https://datanotes.dev/reference/operations/auxiliary/#sync_semantic_index) | Bring the semantic search index up to date: embed the notes changed since the last run (the engine also does it on its own about ten seconds after edits). | [Find notes by meaning](https://datanotes.dev/guides/search/semantic/) |