manage_custom_fields
List, create, or update custom fields for an entity type. Custom fields in Adrata are JSONB-merged, so this tool helps discover existing fields, define conventions, and bulk-update field values. Enterprise only.
This record as markdown: /tools/adrata-starfield-mcp/manage-custom-fields.md
What manage_custom_fields does on Starfield
AI agents use manage_custom_fields to create or update resources in Starfield, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Starfield environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
action | string | Yes | list: discover fields, create: add a new field to records, update: modify field values across records |
entity | string | Yes | Entity type |
fieldName | string | — | Field name (required for create/update) |
targetIds | array | — | Record IDs to update (for update action) |
fieldValue | object | — | Default value for create, or new value for update |
description | string | — | Field description/documentation (stored as cf_meta) |
Parameters from the server's own tool schema.
Why manage_custom_fields is rated Medium
An AI agent can call manage_custom_fields faster than any human can review: one bad instruction and it creates or modifies resources in Starfield by the hundred, each call as confident as the last.
Attacks that exploit this kind of access
The rule that runs manage_custom_fields safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Starfield, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For manage_custom_fields, this is the rule to start with:
manage_custom_fields stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Starfield, apply this rule, and every manage_custom_fields call is checked against it from then on.
Questions about manage_custom_fields
List, create, or update custom fields for an entity type. Custom fields in Adrata are JSONB-merged, so this tool helps discover existing fields, define conventions, and bulk-update field values. Enterprise only. It is categorised as a Write tool in the Starfield MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
manage_custom_fields accepts 6 parameters: action, entity, fieldName, targetIds, fieldValue, description. Required: action, entity. The full parameter table on this page comes from the server's own tool schema.
Register the Starfield MCP server in PolicyLayer and add a rule for manage_custom_fields: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Starfield. Nothing to install.
manage_custom_fields is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the manage_custom_fields rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for manage_custom_fields. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
manage_custom_fields is provided by the Starfield MCP server (@adrata/starfield-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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