Tanod MCP server

skypeek: great-circle distance between airports or points

airport_distance

Read-onlyIdempotent

Calculate the great-circle distance between two airport codes or coordinates, returning kilometers, nautical miles, statute miles, bearings, and midpoint for route reference.

Instructions

skypeek: Calculate the great-circle distance between two airports or points. For airport details use lookup_airport. Returns the great-circle distance between two airports (by code) or coordinates, in km, nautical miles and statute miles, with the initial and final true bearings and the midpoint. Input: from and to: each an airport code or {lat, lon}. Informational only: not for flight planning or navigation. A spherical (haversine) distance, within about 0.5 % of the WGS-84 geodesic. Airports: OurAirports (public domain); the data may contain errors and no endorsement is implied. An unknown code is a 422 unknown_airport (not charged). Typically under 0.1 s. Price: USD 0.001. Free: 5 skypeek calls per IP per UTC day. Docs: https://tanod.dev/learn/airport-lookup-flight-distance-api.html

Input Schema

TableJSON Schema

Name	Required	Description	Default
`to`	Yes	Airport code (ICAO, IATA or ident) or {lat, lon}.
`from`	Yes	Airport code (ICAO, IATA or ident) or {lat, lon}.

Output Schema

TableJSON Schema

Name	Required	Description
`to`	No
`from`	No
`error`	No	Only on an error result: an object {code, message}, or the reason string of an x402 PaymentRequired object.
`method`	No
`source`	No
`midpoint`	No
`disclaimer`	No
`distance_km`	No
`distance_mi`	No
`distance_nm`	No
`final_bearing_deg`	No
`initial_bearing_deg`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Oct 15, 2026

TDQS

A4.6/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare read-only/idempotent/non-destructive, and the description adds substantial extra context: 422 unknown_airport error semantics with 'not charged', latency (<0.1 s), an accuracy bound (~0.5% vs WGS-84), pricing, and a free-tier rate limit. This is well beyond what the annotations carry.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose and the routing hint are front-loaded ahead of the auxiliary detail. It is dense and largely earns its space, though pricing, free-tier quota, and the docs URL are somewhat promotional for a selection-time description.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Return values, error behavior, accuracy caveats, data provenance, cost, and rate limits are all covered. An output schema exists, so return-shape explanation is not strictly required, making the coverage more than sufficient for a two-parameter distance tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the parameter descriptions already state 'Airport code (ICAO, IATA or ident) or {lat, lon}'. The description restates this format and notes the two arguments can be mixed, adding marginal value; baseline of 3 applies when the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Calculate the great-circle distance between two airports or points') and immediately distinguishes itself from the sibling lookup_airport, which handles airport details. An agent can select this over lookup_airport from the description alone.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit routing ('For airport details use lookup_airport') plus a clear exclusion ('Informational only: not for flight planning or navigation'). Both a when-to-use and a when-not-to-use condition are stated, leaving nothing to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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