Check real-time health status of any registered x402 service. Free, no payment required.
AI agents call x402_health to retrieve information from X402 Discovery without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves status information about registered services without modifying any data, executing code, making payments, or triggering external operations. It is a simple monitoring/observability query, which is characteristic of Read-category tools.
From the tool's definition Tool description states it 'Check[s] real-time health status' with 'Free, no payment required.' The verb 'check' and 'health status' indicate a read-only query operation with no side effects.
Attacks that exploit this kind of access
Check real-time health status of any registered x402 service. Free, no payment required. It is categorised as a Read tool in the X402 Discovery MCP Server, which means it retrieves data without modifying state.
Register the X402 Discovery MCP server in PolicyLayer and add a rule for x402_health: 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 X402 Discovery. Nothing to install.
x402_health 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 x402_health 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 x402_health. 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.
x402_health is provided by the X402 Discovery MCP server (rplryan/ouroboros). 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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