snow_add_list_column
Add a column (field) to the default list layout of a table by writing to sys_ui_list_element, with optional position and pixel width. Changes how the list shows up in the UI.
This record as markdown: /tools/serac/snow-add-list-column.md
What snow_add_list_column does on Serac
AI agents use snow_add_list_column to create or update resources in Serac, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Serac environment.
Why snow_add_list_column is rated Medium
This tool creates or modifies UI configuration data (list layout columns) in ServiceNow's sys_ui_list_element table. It is reversible—columns can be removed or modified—and has no financial impact or data destruction. The blast radius is limited to UI/display layer changes affecting how lists appear to users.
From the tool's definition Tool description states 'Add a column (field) to the default list layout' and 'writing to sys_ui_list_element'. The verb 'Add' combined with explicit mention of 'writing to' a system table indicates a create/modify operation.
Attacks that exploit this kind of access
The rule that runs snow_add_list_column safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Serac, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For snow_add_list_column, this is the rule to start with:
snow_add_list_column 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 Serac, apply this rule, and every snow_add_list_column call is checked against it from then on.
Questions about snow_add_list_column
Add a column (field) to the default list layout of a table by writing to sys_ui_list_element, with optional position and pixel width. Changes how the list shows up in the UI. It is categorised as a Write tool in the Serac MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Serac MCP server in PolicyLayer and add a rule for snow_add_list_column: 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 Serac. Nothing to install.
snow_add_list_column 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 snow_add_list_column 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 snow_add_list_column. 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.
snow_add_list_column is provided by the Serac MCP server (serac-labs/serac). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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