AI agents call list_activity to retrieve information from Posterly without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries historical activity and event logs for posts. It has no side effects, creates no data, executes no commands, and modifies nothing. The function is purely informational - listing status changes, publish attempts, failures, and retries that have already occurred. This is a classic Read operation with minimal security risk if misused by an AI agent.
From the tool's definition Tool name is 'list_activity' and description states it 'List[s] recent activity and publish events for posts' - clearly a retrieval operation with 'Use this as the agent notifications feed' indicating it queries existing data without modification.
Attacks that exploit this kind of access
List recent activity and publish events for posts, including status changes, publish attempts, failures, and retries. Use this as the agent notifications feed. It is categorised as a Read tool in the Posterly MCP Server, which means it retrieves data without modifying state.
Register the Posterly MCP server in PolicyLayer and add a rule for list_activity: 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 Posterly. Nothing to install.
list_activity 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_activity 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_activity. 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_activity is provided by the Posterly MCP server (posterly-mcp-server). 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.
Teams ship this data inside their own products. See what a licence covers →