Set the primary contact for a client
AI agents use set_client_primary_contact to create or update resources in Campaign Monitor MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Campaign Monitor MCP environment.
This tool creates or modifies client account metadata (primary contact designation) without irreversibly deleting data or executing arbitrary code. It fits the Write category as a reversible update operation.
From the tool's definition 'Set the primary contact for a client' modifies client account settings by updating who is designated as the primary contact. This is a reversible data modification operation.
Attacks that exploit this kind of access
Set the primary contact for a client. It is categorised as a Write tool in the Campaign Monitor MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Campaign Monitor MCP server in PolicyLayer and add a rule for set_client_primary_contact: 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 Campaign Monitor MCP. Nothing to install.
set_client_primary_contact 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 set_client_primary_contact 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 set_client_primary_contact. 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.
set_client_primary_contact is provided by the Campaign Monitor MCP server (pauliowest/cmon-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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