Query the active SMS subscriber list to retrieve subscriber IDs and phone numbers. Useful for downstream targeting decisions.
AI agents call list_subscribers to retrieve information from Postscript 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 existing subscriber data without creating, modifying, deleting, or executing external operations. It is purely informational (Read). The severity is low because while subscriber lists may contain personally identifiable information, the tool itself performs no destructive or high-impact actions—it simply reads data.
From the tool's definition Tool description states it 'Query[s] the active SMS subscriber list to retrieve subscriber IDs and phone numbers' — a retrieval operation with no modification or side effects.
Attacks that exploit this kind of access
Query the active SMS subscriber list to retrieve subscriber IDs and phone numbers. Useful for downstream targeting decisions. It is categorised as a Read tool in the Postscript MCP Server, which means it retrieves data without modifying state.
Register the Postscript MCP server in PolicyLayer and add a rule for list_subscribers: 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 Postscript. Nothing to install.
list_subscribers 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_subscribers 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_subscribers. 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_subscribers is provided by the Postscript MCP server (nobanks/postscript-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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