Unified tool for ServiceNow On-Call Scheduling. Operates over cmn_rota (rotations), cmn_rota_member (members in a rotation), and cmn_rota_roster (shift assignments) to manage who covers which group at which time. Actions: - list_rotations — list rotations, optionally filtered by assignment group ...
AI agents use snow_oncall_manage 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.
While the tool includes read-only actions (list, get, query), the primary risk comes from swap_shift which reversibly modifies critical on-call assignments. This could disrupt incident response by changing who is scheduled to respond to emergencies, potentially affecting service availability and business continuity.
From the tool's definition Tool performs shift reassignment operations including 'swap_shift' which modifies roster entries in cmn_rota_roster.
Attacks that exploit this kind of access
Unified tool for ServiceNow On-Call Scheduling. Operates over cmn_rota (rotations), cmn_rota_member (members in a rotation), and cmn_rota_roster (shift assignments) to manage who covers which group at which time. Actions: - list_rotations — list rotations, optionally filtered by assignment group - get_current_oncall — resolve who is on call right now for a given rotation (queries cmn_rota_roster against the current GlideDateTime via a server-side helper) - list_shifts — list upcoming shifts/rosters for a rotation within a time window - swap_shift — reassign a roster entry from one rotation member to another Use when: ITSM teams need visibility into on-call coverage, the agent must page the correct person, or a user requests a one-time shift swap. Companion to snow_create_schedule for the underlying schedule definitions. Returns: action-specific structures. list_rotations returns rotation records with assignment_group and schedule references. get_current_oncall returns the active rotation member (sys_user link) plus the roster row that grants coverage. list_shifts returns roster rows ordered by start time. swap_shift returns the updated roster record. 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_oncall_manage: 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_oncall_manage 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_oncall_manage 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_oncall_manage. 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_oncall_manage 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.
snow_oncall_manage is one line of Serac's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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