AI agents call getUserBio to retrieve information from Twitter Client MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves user biographical information from Twitter without modifying, executing, or deleting anything. It is a straightforward GET operation with no side effects, fitting the Read category. The low severity reflects minimal blast radius—returning public user bio data poses negligible risk even if misused by an AI agent.
From the tool's definition Tool name 'getUserBio' and description 'Get a Twitter user' indicate data retrieval. Sibling tools like 'getTweet', 'getUserTweets', 'getTwitterFollowers' confirm this server provides read-only query operations.
Documented attack patterns abuse exactly the kind of access getUserBio gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Twitter Client MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for getUserBio:
{
"version": "1",
"default": "deny",
"tools": {
"getUserBio": {}
}
}getUserBio is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get a Twitter user. It is categorised as a Read tool in the Twitter Client MCP MCP Server, which means it retrieves data without modifying state.
Register the Twitter Client MCP server in PolicyLayer and add a rule for getUserBio: 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 Twitter Client MCP. Nothing to install.
getUserBio 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 getUserBio 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 getUserBio. 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.
getUserBio is provided by the Twitter Client MCP server (mzkrasner/twitter-client-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Twitter Client MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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20 Twitter Client MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.