AI agents call x_get_user_by_id to retrieve information from X without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries X API v2 to fetch publicly available user profile information based on a numeric ID. It is read-only retrieval with no ability to modify data, execute actions, or cause destructive effects. The blast radius of misuse is minimal—an attacker could enumerate user IDs or gather public profile data, but cannot modify, delete, or perform actions on behalf of the authenticated user.
From the tool's definition Tool performs a lookup operation that 'retrieves' user information by ID. The description uses 'Look up', which is a query/retrieval action with no modification, deletion, or side effects.
Attacks that exploit this kind of access
Look up an X user by their numeric user ID. It is categorised as a Read tool in the X MCP Server, which means it retrieves data without modifying state.
Register the X MCP server in PolicyLayer and add a rule for x_get_user_by_id: 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 X. Nothing to install.
x_get_user_by_id 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 x_get_user_by_id 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 x_get_user_by_id. 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.
x_get_user_by_id is provided by the X MCP server (mindmadelab/x-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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