Check whether a coordinate (latitude, longitude in decimal degrees) is on water or land, and how far it is from the coast. Returns: - is_water: boolean (true if over sea, false if over land) - distance_to_coast_m: meters to the nearest coastline boundary; meaningful on either side (sea → distance...
Part of the Nausika server.
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AI agents call nausika_is_water 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_is_water 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_is_water": {}
}
}See the full Nausika policy for all 19 tools.
These attack patterns abuse exactly the kind of access nausika_is_water 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.
Check whether a coordinate (latitude, longitude in decimal degrees) is on water or land, and how far it is from the coast. Returns: - is_water: boolean (true if over sea, false if over land) - distance_to_coast_m: meters to the nearest coastline boundary; meaningful on either side (sea → distance to shore, inland → distance to sea, e.g. Rome ≈ 25 km). - source: detection source Useful to verify waypoints in route planning, or to gauge how coastal/inland a point is.. 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_is_water: 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_is_water 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_is_water 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_is_water. 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_is_water 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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