Historical National Bank of Romania (BNR) official FX reference rates, parsed from XML. With no arguments (or period="10days") returns the last 10 published business days. Pass year=YYYY (e.g. 2024) to return every published day in that calendar year. Returns an array of daily entries, each { dat...
Risk signalsBulk/mass operation — affects multiple targets
Part of the Bnr Ro server.
Free to start. No card required.
AI agents use exchange_rates_history to create or modify resources in Bnr Ro. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call exchange_rates_history repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Bnr Ro.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"exchange_rates_history": {
"limits": [
{
"counter": "exchange_rates_history_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Bnr Ro policy for all 22 tools.
These attack patterns abuse exactly the kind of access exchange_rates_history gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Historical National Bank of Romania (BNR) official FX reference rates, parsed from XML. With no arguments (or period="10days") returns the last 10 published business days. Pass year=YYYY (e.g. 2024) to return every published day in that calendar year. Returns an array of daily entries, each { date, rates:[{currency, value, multiplier}] }. Each rate is RON per multiplier units of the currency; per-1-unit rate = value / multiplier. Currencies are ISO 4217 codes. Note the currency set can vary across dates.. It is categorised as a Write tool in the Bnr Ro MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Bnr Ro MCP server in PolicyLayer and add a rule for exchange_rates_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 Bnr Ro. Nothing to install.
exchange_rates_history is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the exchange_rates_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 exchange_rates_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.
exchange_rates_history is provided by the Bnr Ro MCP server (https://gateway.pipeworx.io/bnr-ro/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 22 Bnr Ro tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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