AI agents call list_contact_fields to retrieve information from Systemeio without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves metadata about contact field definitions in the Systeme.io account. It performs a non-destructive, read-only operation that returns structured information without side effects. No data is created, modified, deleted, or executed.
From the tool's definition Tool name is 'list_contact_fields' and description states it 'List all custom contact fields' — a retrieval operation with no modification or deletion of data.
Attacks that exploit this kind of access
List all custom contact fields defined in your Systeme.io account (e.g., first_name, country, phone_number, and any custom fields you created). It is categorised as a Read tool in the Systemeio MCP Server, which means it retrieves data without modifying state.
Register the Systemeio MCP server in PolicyLayer and add a rule for list_contact_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 Systemeio. Nothing to install.
list_contact_fields is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_contact_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 list_contact_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.
list_contact_fields is provided by the Systemeio MCP server (snzeeee/mcp-server-systemeio). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
list_contact_fields is one line of Systemeio'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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