Verify that an incoming webhook callback came from PicPay by comparing the x-seller-token header against PICPAY_SELLER_TOKEN. Use this in your callback handler before trusting the payload, then call get_payment_status to fetch the authoritative status.
AI agents call validate_notification to retrieve information from Mcp Afip without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool reads and validates webhook data (header comparison) without creating, modifying, deleting, or executing external actions. It is a defensive security check that should occur before processing, making it a Read operation. Severity is low because misuse would only prevent legitimate webhook validation, not expose or compromise data.
From the tool's definition Tool performs verification/validation of an incoming webhook callback by comparing headers. The description explicitly states 'Verify', 'comparing', and 'before trusting the payload' — these are authentication and integrity checks with no data modification or…
Documented attack patterns abuse exactly the kind of access validate_notification gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Afip, and nothing reaches the server without passing your rules. This is the rule we recommend for validate_notification:
{
"version": "1",
"default": "deny",
"tools": {
"validate_notification": {}
}
}validate_notification is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Verify that an incoming webhook callback came from PicPay by comparing the x-seller-token header against PICPAY_SELLER_TOKEN. Use this in your callback handler before trusting the payload, then call get_payment_status to fetch the authoritative status. It is categorised as a Read tool in the Mcp Afip MCP Server, which means it retrieves data without modifying state.
Register the Mcp Afip MCP server in PolicyLayer and add a rule for validate_notification: 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 Mcp Afip. Nothing to install.
validate_notification 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 validate_notification 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 validate_notification. 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.
validate_notification is provided by the Mcp Afip MCP server (codespar/mcp-dev-latam). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Afip, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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1300 Mcp Afip tools catalogued and risk-classified — across an index of 43,000+ MCP servers.