AI agents use follow_user to create or update resources in X(Twitter) V2 MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your X(Twitter) V2 MCP Server environment.
Following a user on Twitter/X creates a social relationship (a reversible write action). While the description is empty, the tool name strongly implies it triggers a follow action via the Twitter API, which is a reversible write operation. Confidence is reduced due to the lack of description.
From the tool's definition Tool name 'follow_user' on a Twitter/X API server; description is empty and uninformative.
Documented attack patterns abuse exactly the kind of access follow_user gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and X(Twitter) V2 MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for follow_user:
{
"version": "1",
"default": "deny",
"tools": {
"follow_user": {
"limits": [
{
"counter": "follow_user_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}follow_user stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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follow_user. It is categorised as a Write tool in the X(Twitter) V2 MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the X(Twitter) V2 MCP Server MCP server in PolicyLayer and add a rule for follow_user: 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) V2 MCP Server. Nothing to install.
follow_user is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the follow_user 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 follow_user. 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.
follow_user is provided by the X(Twitter) V2 MCP Server MCP server (nexusx-mcp/x-v2-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from X(Twitter) V2 MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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16 X(Twitter) V2 MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.