AI agents call get_user_mentions to retrieve information from X (Twitter) MCP server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves/queries existing tweets that mention a user. It performs a read-only operation with no capability to modify, delete, execute code, or affect financial systems. The blast radius of misuse is minimal—at worst, an AI agent could retrieve and aggregate mentions of a user, which is already public information on Twitter/X.
From the tool's definition Tool name 'get_user_mentions' and description 'Get tweets mentioning a specific user' indicate data retrieval with no side effects.
Documented attack patterns abuse exactly the kind of access get_user_mentions gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and X (Twitter) MCP server, and nothing reaches the server without passing your rules. This is the rule we recommend for get_user_mentions:
{
"version": "1",
"default": "deny",
"tools": {
"get_user_mentions": {}
}
}get_user_mentions is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get tweets mentioning a specific user. It is categorised as a Read tool in the X (Twitter) MCP server MCP Server, which means it retrieves data without modifying state.
Register the X (Twitter) MCP server MCP server in PolicyLayer and add a rule for get_user_mentions: 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 (Twitter) MCP server. Nothing to install.
get_user_mentions 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 get_user_mentions 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 get_user_mentions. 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.
get_user_mentions is provided by the X (Twitter) MCP server MCP server (rafaljanicki/x-twitter-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 24 X (Twitter) MCP server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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24 X (Twitter) MCP server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.