AI agents call list_x402_categories to retrieve information from X402hub without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a simple query/browse operation that retrieves metadata about available service categories. It has no ability to modify data, execute operations, delete anything, or commit financial transactions. The blast radius of misuse is minimal—an AI agent cannot cause harm by calling this tool multiple times or with any argument variations.
From the tool's definition Tool name 'list_x402_categories' and description 'List the categories...to browse what capabilities exist' indicates data retrieval only. Returns enumeration and counts with no modifications, side effects, or external operations triggered.
Attacks that exploit this kind of access
List the categories of x402 services and how many are in each, to browse what capabilities exist. It is categorised as a Read tool in the X402hub MCP Server, which means it retrieves data without modifying state.
Register the X402hub MCP server in PolicyLayer and add a rule for list_x402_categories: 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 X402hub. Nothing to install.
list_x402_categories 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 list_x402_categories 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 list_x402_categories. 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.
list_x402_categories is provided by the X402hub MCP server (zacharytroberts03-ctrl/x402hub). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
list_x402_categories is one line of X402hub's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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