Look up audience segments to see how many subscribers each contains. Use BEFORE drafting an SMS blast so the agent can scope the campaign correctly.
AI agents call check_segment_size 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 retrieves aggregate count data about subscriber segments without creating, modifying, deleting, or executing any operations. It is purely informational. Exposure of segment sizes poses minimal risk—the data itself is not sensitive customer information and cannot be misused to cause harm or financial loss. This is a standard Read category tool.
From the tool's definition Tool description states 'Look up audience segments to see how many subscribers each contains' - a pure query/retrieval operation with no modification or side effects.
Attacks that exploit this kind of access
Look up audience segments to see how many subscribers each contains. Use BEFORE drafting an SMS blast so the agent can scope the campaign correctly. 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 check_segment_size: 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.
check_segment_size 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 check_segment_size 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 check_segment_size. 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.
check_segment_size 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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