Validate a US bank ABA routing number with the Federal Reserve weighted mod-10 (3-7-1) checksum, not just a regex. Returns valid, routingNumber, and routing-symbol district. Catches transposed digits in ACH/wire setup.
AI agents call validate.aba to retrieve information from Mcp without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves validation status and metadata about a routing number without creating, modifying, deleting, or executing any operation. It is purely informational (Read category). Severity is low because misuse cannot cause financial harm—it only validates pre-existing routing numbers without moving money or committing financial obligations.
From the tool's definition Tool performs validation-only operation: 'Validate a US bank ABA routing number' and 'Returns valid, routingNumber, and routing-symbol district.' No modification, execution, or financial transaction occurs—it only checks and returns information about an…
Attacks that exploit this kind of access
Validate a US bank ABA routing number with the Federal Reserve weighted mod-10 (3-7-1) checksum, not just a regex. Returns valid, routingNumber, and routing-symbol district. Catches transposed digits in ACH/wire setup. It is categorised as a Read tool in the Mcp MCP Server, which means it retrieves data without modifying state.
Register the MCP server in PolicyLayer and add a rule for validate.aba: 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. Nothing to install.
validate.aba 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.aba 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.aba. 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.aba is provided by the MCP server (@2sio/mcp). 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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