> ## Documentation Index > Fetch the complete documentation index at: https://docs.gc.ai/llms.txt > Use this file to discover all available pages before exploring further. # Create vault column > Add a column to a vault, so GC AI extracts one more thing from its documents. The MCP server is in public beta. It is open to use and still being refined, so tools and behavior may change. **Tool** `create_vault_column` · **Behavior** Additive Add a column to a vault, so GC AI extracts one more thing from its documents. Adding a column does NOT read the documents already in the vault: it starts empty for all of them and fills in for documents added afterwards. Backfilling the existing ones is a separate action someone takes in the app, so say so rather than waiting for values to appear. A vault holds at most 500 columns. ## Input parameters The vault to add the column to. Column heading people see. What the AI should look for in each document. Required for an `ai` column, which is the default. One of: text, rich\_text, date, date\_range, enum, multi\_enum, boolean, number, currency, percentage, duration, email, url, list. Defaults to text. `enum` and `multi_enum` need `field_meta`. The choices for an enum or multi-select column: 2 to 12 unique options. Must be null for every other column type. `ai` (the default) has GC AI fill the column. `manual` leaves it for people to fill in. The stable key for this column in `get_vault_documents`. Omit and GC AI derives it from the label. It never changes, even if the label does. ## Response