Compare current prices between 2-5 commodities side by side. Use when the user asks to compare commodities (e.g., 'Brent vs WTI', 'US gas vs EU gas'). Returns each commodity's price with 24h changes, plus the spread if comparing two same-currency commodities. Accepts natural language or codes.
Part of the Oilpriceapi server.
Free to start. No card required.
AI agents call opa_compare_prices to retrieve information from Oilpriceapi 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 opa_compare_prices 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": {
"opa_compare_prices": {}
}
}See the full Oilpriceapi policy for all 14 tools.
These attack patterns abuse exactly the kind of access opa_compare_prices 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.
Compare current prices between 2-5 commodities side by side. Use when the user asks to compare commodities (e.g., 'Brent vs WTI', 'US gas vs EU gas'). Returns each commodity's price with 24h changes, plus the spread if comparing two same-currency commodities. Accepts natural language or codes.. It is categorised as a Read tool in the Oilpriceapi MCP Server, which means it retrieves data without modifying state.
Register the Oilpriceapi MCP server in PolicyLayer and add a rule for opa_compare_prices: 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 Oilpriceapi. Nothing to install.
opa_compare_prices 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 opa_compare_prices 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 opa_compare_prices. 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.
opa_compare_prices is provided by the Oilpriceapi MCP server (OilpriceAPI/oilpriceapi-api). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 14 Oilpriceapi tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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