Average interest rates Treasury pays on its outstanding securities by security type. Answers "what is the government's cost of borrowing?" Covers Bills, Notes, Bonds, TIPS, Floating Rate Notes, and aggregate marketable/non-marketable totals. Updated monthly (end-of-month records). Mode "latest" r...
Part of the Treasury Fiscaldata Mcp Server server.
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AI agents call treasury_get_interest_rates to retrieve information from Treasury Fiscaldata Mcp Server 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 treasury_get_interest_rates 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": {
"treasury_get_interest_rates": {}
}
}See the full Treasury Fiscaldata Mcp Server policy for all 7 tools.
These attack patterns abuse exactly the kind of access treasury_get_interest_rates 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.
Average interest rates Treasury pays on its outstanding securities by security type. Answers "what is the government's cost of borrowing?" Covers Bills, Notes, Bonds, TIPS, Floating Rate Notes, and aggregate marketable/non-marketable totals. Updated monthly (end-of-month records). Mode "latest" returns the most recent month's rates for all or one security type; "series" returns a time history. As of 2026-04-30: Bills 3.696%, Notes 3.230%, Bonds 3.403%, TIPS 1.068%, FRN 3.764%, Total Interest-bearing Debt 3.340%.. It is categorised as a Read tool in the Treasury Fiscaldata Mcp Server MCP Server, which means it retrieves data without modifying state.
Register the Treasury Fiscaldata Mcp Server MCP server in PolicyLayer and add a rule for treasury_get_interest_rates: 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 Treasury Fiscaldata Mcp Server. Nothing to install.
treasury_get_interest_rates 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 treasury_get_interest_rates 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 treasury_get_interest_rates. 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.
treasury_get_interest_rates is provided by the Treasury Fiscaldata Mcp Server MCP server (@cyanheads/treasury-fiscaldata-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 7 Treasury Fiscaldata Mcp Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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