Before calling any Vybe endpoint without an API key (e.g. AI agent, throwaway script, premium-only path), use this to access the same endpoint via x402 pay-per-call USDC on Solana.
Part of the Solana MCP by Vybe server.
Free to start. No card required.
AI agents use pay-with-x402 to initiate financial transactions through Solana MCP by Vybe. Financial operations involve real money and are irreversible once processed. PolicyLayer blocks financial tools by default, requiring explicit human approval with transaction-level limits to prevent unauthorised spending.
pay-with-x402 moves real money. Without a policy, an autonomous agent could initiate transactions that drain accounts or exceed budgets. PolicyLayer blocks financial tools by default, requiring human-in-the-loop approval with configurable spending limits per transaction and per time window.
Financial tools involve real money. Block by default and require explicit human approval before enabling.
{
"version": "1",
"default": "deny",
"tools": {
"pay-with-x402": {
"deny_if": [
{
"conditions": [],
"on_deny": "Requires human approval."
}
]
}
}
}See the full Solana MCP by Vybe policy for all 5 tools.
These attack patterns abuse exactly the kind of access pay-with-x402 gives an agent. Each links to the full case and the policy that stops it:
Other financial tools across the catalogue. The same approach applies to each: deny by default, or require human approval.
Before calling any Vybe endpoint without an API key (e.g. AI agent, throwaway script, premium-only path), use this to access the same endpoint via x402 pay-per-call USDC on Solana.. It is categorised as a Financial tool in the Solana MCP by Vybe MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Register the Solana MCP by Vybe MCP server in PolicyLayer and add a rule for pay-with-x402: 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 Solana MCP by Vybe. Nothing to install.
pay-with-x402 is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the pay-with-x402 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 pay-with-x402. 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.
pay-with-x402 is provided by the Solana MCP by Vybe MCP server (https://docs.vybenetwork.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 5 Solana MCP by Vybe 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.