Evaluate a math expression and return the numeric result. Useful for fuel, range/autonomy, unit conversions, and ad-hoc arithmetic. Supported (exhaustive): +, -, *, /, ^, %, parentheses, sqrt(), abs(), ceil(), floor(), round(), sin(), cos(), tan(), log(), exp(), min(), max(), PI, E. Anything else...
Risk signalsAccepts freeform code/query input (expression)
Part of the Nausika server.
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AI agents call nausika_calculator to retrieve information from Nausika 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 nausika_calculator 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": {
"nausika_calculator": {}
}
} See the full Nausika policy for all 19 tools.
These attack patterns abuse exactly the kind of access nausika_calculator 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.
Evaluate a math expression and return the numeric result. Useful for fuel, range/autonomy, unit conversions, and ad-hoc arithmetic. Supported (exhaustive): +, -, *, /, ^, %, parentheses, sqrt(), abs(), ceil(), floor(), round(), sin(), cos(), tan(), log(), exp(), min(), max(), PI, E. Anything else (atan2, pow, log10, hypot, if, factorial, comparisons) is rejected. Examples: "(120 / 6) * 8.5" (fuel for 120 nm at 8.5 L/h, 6 kn); "45 * 1.852" (nm to km).. It is categorised as a Read tool in the Nausika MCP Server, which means it retrieves data without modifying state.
Register the Nausika MCP server in PolicyLayer and add a rule for nausika_calculator: 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 Nausika. Nothing to install.
nausika_calculator 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 nausika_calculator 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 nausika_calculator. 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.
nausika_calculator is provided by the Nausika MCP server (https://mcp.nausika.app). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 19 Nausika tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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