calculate_haversine_distance
Use this when you need the straight-line distance between two GPS coordinates or cities, e.g. for flight distance, range checks or geofencing. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need ro...
This record as markdown: /tools/com-tttkmbb-calcgrid/calculate-haversine-distance.md
What calculate_haversine_distance does on Calcgrid
AI agents call calculate_haversine_distance to retrieve information from Calcgrid without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
lat1 | number | Yes | Latitude of point 1 in decimal degrees (north positive, south negative). Unit: °. |
lat2 | number | Yes | Latitude of point 2 in decimal degrees (north positive, south negative). Unit: °. |
lon1 | number | Yes | Longitude of point 1 in decimal degrees (east positive, west negative). Unit: °. |
lon2 | number | Yes | Longitude of point 2 in decimal degrees (east positive, west negative). Unit: °. |
Parameters from the server's own tool schema.
Why calculate_haversine_distance is rated Low
Even though calculate_haversine_distance only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs calculate_haversine_distance safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Calcgrid, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For calculate_haversine_distance, this is the rule to start with:
calculate_haversine_distance is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Calcgrid, apply this rule, and every calculate_haversine_distance call is checked against it from then on.
Questions about calculate_haversine_distance
Use this when you need the straight-line distance between two GPS coordinates or cities, e.g. for flight distance, range checks or geofencing. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need road distance, or ellipsoidal accuracy better than about 0.5 % (use a geodesic method such as Vincenty or Karney on WGS-84); for bearings and compass points use compass-bearing. What it computes: Computes the great-circle (as-the-crow-flies) distance between two points on a spherical Earth with the haversine formula, in kilometres, miles and nautical miles, together with the initial bearing, compass direction and the midpoint of the route. Inputs: lat1 (number, °); lon1 (number, °); lat2 (number, °); lon2 (number, °). Complete JSON argument examples: {"lat1":-33.8688,"lon1":151.2093,"lat2":35.6762,"lon2":139.6503} | {"lat1":50.06639,"lon1":-5.71472,"lat2":58.64389,"lon2":-3.07} Outputs: distance_km [km], distance_miles [mi], distance_nautical_miles [nmi], central_angle_degrees [°], initial_bearing_degrees [°], compass_direction, midpoint_lat [°], midpoint_lon [°]. Formula: a = sin²(Δφ/2) + cos φ1 · cos φ2 · sin²(Δλ/2); c = 2 · atan2(√a, √(1−a)); d = R · c with R = 6371.0088 km; θ = atan2(sin Δλ · cos φ2, cos φ1 · sin φ2 − sin φ1 · cos φ2 · cos Δλ) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/haversine-distance with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/time/haversine-distance.md. It is categorised as a Read tool in the Calcgrid MCP Server, which means it retrieves data without modifying state.
calculate_haversine_distance accepts 4 parameters: lat1, lat2, lon1, lon2. Required: lat1, lat2, lon1, lon2. The full parameter table on this page comes from the server's own tool schema.
Register the Calcgrid MCP server in PolicyLayer and add a rule for calculate_haversine_distance: 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 Calcgrid. Nothing to install.
calculate_haversine_distance 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 calculate_haversine_distance 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 calculate_haversine_distance. 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.
calculate_haversine_distance is provided by the Calcgrid MCP server (https://tttkmbb.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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