AI agents call hn_user to retrieve information from UnClick without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
username | string | Yes |
Parameters from the server's own tool schema.
This tool queries and retrieves publicly available user profile data from Hacker News. 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—an agent could only retrieve user profile information already publicly available on the platform.
From the tool's definition Tool name 'hn_user' and description 'Get a Hacker News user profile' indicate a retrieval operation with no side effects.
Attacks that exploit this kind of access
Get a Hacker News user profile. It is categorised as a Read tool in the UnClick MCP Server, which means it retrieves data without modifying state.
hn_user accepts 1 parameter: username. Required: username. The full parameter table on this page comes from the server's own tool schema.
Register the UnClick MCP server in PolicyLayer and add a rule for hn_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 UnClick. Nothing to install.
hn_user 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 hn_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 hn_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.
hn_user is provided by the UnClick MCP server (@unclick/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.
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