> ## Documentation Index
> Fetch the complete documentation index at: https://www.rootset.app/llms.txt
> Use this file to discover all available pages before exploring further.

# rootset_create_field

> Add a validated field, checking existing values and row bytes.

## Workflow

```mermaid theme={"system"}
flowchart LR
  discover["Read the table schema"] --> invoke["Create field"]
  invoke --> outcome["Check the job result"]
```

## Access and behavior

Requires a current workspace role of **Member** or higher. The connection needs `schema:manage` scope.

* This tool changes data or starts work. Confirm the target and input before calling it.
* Keep the same `idempotencyKey` when retrying an unchanged request; use a new key for different input.
* Read the current table schema before supplying `expectedSchemaVersion`.
* A returned job is pending work. Use [rootset\_get\_job](/mcp-reference/rootset_get_job) to check its final result.

## Arguments

| Argument | Required | Type | Details |
| - | - | - | - |
| `orgId` | Yes | string | Workspace ID returned by rootset\_get\_context. |
| `databaseId` | Yes | string | ID of the database to work with. |
| `tableId` | Yes | string | ID of the table to work with. |
| `expectedSchemaVersion` | Yes | integer | Current version returned by the table schema. |
| `field` | Yes | object | — |
| `idempotencyKey` | Yes | string | Stable caller-provided key across retries of this exact operation. |

<Accordion title="Complete input schema">
  ```json theme={"system"}
  {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "orgId": {
        "type": "string",
        "pattern": "^[0-7][0-9A-HJKMNP-TV-Z]{25}$"
      },
      "databaseId": {
        "type": "string",
        "pattern": "^[0-7][0-9A-HJKMNP-TV-Z]{25}$"
      },
      "tableId": {
        "type": "string",
        "pattern": "^[0-7][0-9A-HJKMNP-TV-Z]{25}$"
      },
      "expectedSchemaVersion": {
        "type": "integer",
        "minimum": 1,
        "maximum": 2147483647
      },
      "field": {
        "anyOf": [
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "text"
              },
              "allowedValues": {
                "anyOf": [
                  {
                    "minItems": 1,
                    "maxItems": 100,
                    "type": "array",
                    "items": {
                      "type": "string",
                      "minLength": 1,
                      "maxLength": 4096
                    },
                    "description": "1–100 distinct nonempty exact text choices; up to 4,096 Unicode characters per choice and 65,536 UTF-8 bytes for the whole list. Optional cells may be null; defaults must be listed.",
                    "uniqueItems": true,
                    "x-rootset-max-utf8-bytes": 65536
                  },
                  {
                    "type": "null"
                  }
                ]
              },
              "charLimit": {
                "type": "integer",
                "exclusiveMinimum": 0,
                "maximum": 65536
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "integer"
              },
              "autoIncrement": {
                "description": "Generate increasing safe integers when a value is omitted on creation. Explicit IDs advance the durable counter. Cannot be combined with a constant default.",
                "type": "boolean"
              },
              "min": {
                "type": "integer",
                "minimum": -9007199254740991,
                "maximum": 9007199254740991
              },
              "max": {
                "type": "integer",
                "minimum": -9007199254740991,
                "maximum": 9007199254740991
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "float"
              },
              "min": {
                "type": "number"
              },
              "max": {
                "type": "number"
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "uri"
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "url"
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "image"
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "boolean"
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "date"
              },
              "min": {
                "type": "string",
                "pattern": "^(?!0000)\\d{4}-\\d{2}-\\d{2}$",
                "format": "date",
                "examples": ["2024-01-01"]
              },
              "max": {
                "type": "string",
                "pattern": "^(?!0000)\\d{4}-\\d{2}-\\d{2}$",
                "format": "date",
                "examples": ["2024-01-01"]
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "time"
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "date-time"
              },
              "min": {
                "type": "string",
                "pattern": "^(?!0000)\\d{4}-\\d{2}-\\d{2}T(?:[01]\\d|2[0-3]):[0-5]\\d:[0-5]\\d(?:\\.\\d{1,3})?Z$",
                "format": "date-time",
                "description": "UTC instant with mandatory Z and at most three fractional digits.",
                "examples": ["2024-01-01T12:30:00.000Z"]
              },
              "max": {
                "type": "string",
                "pattern": "^(?!0000)\\d{4}-\\d{2}-\\d{2}T(?:[01]\\d|2[0-3]):[0-5]\\d:[0-5]\\d(?:\\.\\d{1,3})?Z$",
                "format": "date-time",
                "description": "UTC instant with mandatory Z and at most three fractional digits.",
                "examples": ["2024-01-01T12:30:00.000Z"]
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          },
          {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "minLength": 1,
                "maxLength": 64,
                "pattern": "^[A-Za-z_]+$"
              },
              "required": {
                "type": "boolean"
              },
              "default": {
                "description": "Any finite JSON value. Cell size/depth and typed numeric policies are enforced by the domain validator.",
                "anyOf": [
                  {
                    "type": "null"
                  },
                  {
                    "type": "boolean"
                  },
                  {
                    "type": "number"
                  },
                  {
                    "type": "string"
                  },
                  {
                    "type": "array",
                    "items": {}
                  },
                  {
                    "type": "object",
                    "additionalProperties": {}
                  }
                ]
              },
              "order": {
                "type": "integer",
                "minimum": 0,
                "maximum": 199
              },
              "type": {
                "type": "string",
                "const": "json"
              }
            },
            "required": ["name", "type"],
            "additionalProperties": false
          }
        ]
      },
      "idempotencyKey": {
        "type": "string",
        "minLength": 8,
        "maxLength": 255,
        "description": "Stable caller-provided key across retries of this exact operation."
      }
    },
    "required": [
      "orgId",
      "databaseId",
      "tableId",
      "expectedSchemaVersion",
      "field",
      "idempotencyKey"
    ],
    "additionalProperties": false
  }
  ```
</Accordion>

## Example call

Your client initializes the MCP connection before this call. Example identifiers and values are illustrative; use the IDs, schema version and values from your installation.

```json theme={"system"}
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "rootset_create_field",
    "arguments": {
      "orgId": "01K6J7B8000000000000000000",
      "databaseId": "01K6J7B8000000000000000000",
      "tableId": "01K6J7B8000000000000000000",
      "expectedSchemaVersion": 1,
      "field": {
        "name": "example",
        "type": "text"
      },
      "idempotencyKey": "example-request-0001"
    }
  }
}
```

## Result

Read the structured result returned by the tool. A tool failure sets `isError`; do not treat an error as a completed operation. The [REST operation](/api-reference/createField) documents the corresponding result fields and errors.

[Connect an MCP client](/mcp-guide) · [REST conventions](/api-reference/overview)


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