Retrieves live and historical fiat currency exchange rates from the Frankfurter API (sourced from the European Central Bank). Supports both real-time conversion and historical rate lookup for any past date, making it the preferred tool when auditable, ECB-sourced rate data is required. Use curren...
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AI agents call currency_rates to retrieve information from Inferventis — Financial Data, News & Web MCP 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 currency_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": {
"currency_rates": {}
}
}See the full Inferventis — Financial Data, News & Web MCP policy for all 20 tools.
These attack patterns abuse exactly the kind of access currency_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.
Retrieves live and historical fiat currency exchange rates from the Frankfurter API (sourced from the European Central Bank). Supports both real-time conversion and historical rate lookup for any past date, making it the preferred tool when auditable, ECB-sourced rate data is required. Use currency_rates when a rate from a specific past date is required (e.g. accounting, tax, or audit), or when the ECB source must be documented. Prefer currency_convert when only a live conversion is needed with a richer structured response. Prefer currency_convert_lite for lightweight live ECB conversions without historical requirements. Prefer currency_fx_lite when ECB sourcing is not required and only a lightweight live result is needed. Use currency_convert_open when a non-ECB rate source is acceptable and Frankfurter is unavailable. Does not support cryptocurrency pairs — use crypto_fx_rates for any conversion involving a digital asset.. It is categorised as a Read tool in the Inferventis — Financial Data, News & Web MCP MCP Server, which means it retrieves data without modifying state.
Register the Inferventis — Financial Data, News & Web MCP server in PolicyLayer and add a rule for currency_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 Inferventis — Financial Data, News & Web MCP. Nothing to install.
currency_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 currency_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 currency_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.
currency_rates is provided by the Inferventis — Financial Data, News & Web MCP server (https://mcp-server-295985738387.europe-west1.run.app/mcp-pay?src=registry). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 20 Inferventis — Financial Data, News & Web MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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