Daily time series of the official NBU rate for ONE currency over a date range. Pass valcode (ISO-4217, e.g. USD) and start/end as YYYYMMDD. Returns one record per business day: {exchangedate (DD.MM.YYYY), cc, txt (Ukrainian name), enname (English name), rate (UAH per units), units, rate_per_unit}...
Part of the Nbu Ua server.
Free to start. No card required.
AI agents invoke currency_history to trigger processes or run actions in Nbu Ua. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.
currency_history can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. PolicyLayer enforces rate limits and validates arguments to keep execution within safe bounds.
Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.
{
"version": "1",
"default": "deny",
"tools": {
"currency_history": {
"limits": [
{
"counter": "currency_history_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}See the full Nbu Ua policy for all 25 tools.
These attack patterns abuse exactly the kind of access currency_history gives an agent. Each links to the full case and the policy that stops it:
Other execute tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Daily time series of the official NBU rate for ONE currency over a date range. Pass valcode (ISO-4217, e.g. USD) and start/end as YYYYMMDD. Returns one record per business day: {exchangedate (DD.MM.YYYY), cc, txt (Ukrainian name), enname (English name), rate (UAH per units), units, rate_per_unit}. Omit valcode to get every currency over the range. Newest first.. It is categorised as a Execute tool in the Nbu Ua MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Nbu Ua MCP server in PolicyLayer and add a rule for currency_history: 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 Nbu Ua. Nothing to install.
currency_history is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the currency_history 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_history. 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_history is provided by the Nbu Ua MCP server (https://gateway.pipeworx.io/nbu-ua/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 25 Nbu Ua tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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