Create a deterministic, read-only pre-action receipt from request, policy, and optional result evidence. Use before an agent posts, spends, lists, or writes so the decision can be audited; no external action is executed.
Part of the Boundary Guard x402 server.
Free to start. No card required.
AI agents call boundary_guard_check to retrieve information from Boundary Guard x402 without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though boundary_guard_check only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"boundary_guard_check": {}
}
}See the full Boundary Guard x402 policy for all 6 tools.
These attack patterns abuse exactly the kind of access boundary_guard_check gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Create a deterministic, read-only pre-action receipt from request, policy, and optional result evidence. Use before an agent posts, spends, lists, or writes so the decision can be audited; no external action is executed.. It is categorised as a Read tool in the Boundary Guard x402 MCP Server, which means it retrieves data without modifying state.
Register the Boundary Guard x402 MCP server in PolicyLayer and add a rule for boundary_guard_check: 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 Boundary Guard x402. Nothing to install.
boundary_guard_check 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 boundary_guard_check 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 boundary_guard_check. 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.
boundary_guard_check is provided by the Boundary Guard x402 MCP server (https://x402-resource-scanner.vercel.app/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 6 Boundary Guard x402 tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.