Tanod MCP server

skypeek: satellite passes over a location (ISS and others)

satellite_passes

Read-onlyIdempotent

Predict when satellites like the ISS pass over a latitude and longitude in the next 1–3 days, with times, azimuth, elevation, duration, and eye visibility.

Instructions

skypeek: Predict satellite passes over a location. For sun and moon times use sun_moon_times. Returns the passes of a satellite (default the ISS) over a point in the next 1-3 days: start, highest and end times with azimuth and elevation, duration, and whether the pass is visible to the eye. SGP4 predictions, not observations, from CelesTrak orbital elements (only derived pass times are returned; no endorsement by CelesTrak implied). Satellites: CelesTrak's 'stations' and 'visual' groups plus NOAA 15 / 18 / 19; another NORAD id is a 422 (not charged). At most 40 passes. A cold orbital-data cache or an upstream outage can be a 503 (not charged; retry). Typically under 1 s; with a cold orbital-data cache up to a minute or more (a 503 when too slow, not charged: retry). Price: USD 0.002. Free: 5 skypeek calls per IP per UTC day. Docs: https://tanod.dev/learn/iss-pass-times-api.html

Input Schema

TableJSON Schema

Name	Required	Description
`lat`	Yes	Latitude in degrees (-90 to 90).
`lon`	Yes	Longitude in degrees (-180 to 180).
`days`	No	Window in days (1-3).
`alt_m`	No	Observer altitude in metres.
`norad_id`	No	NORAD catalog number (default 25544, the ISS); CelesTrak 'stations' and 'visual' groups plus NOAA 15 / 18 / 19.
`visible_only`	No	Only passes that can be seen with the eye (satellite sunlit, sky dark).
`min_elevation`	No	Lowest elevation counted as a pass, in degrees above the horizon.

Output Schema

TableJSON Schema

Name	Required	Description
`lat`	No
`lon`	No
`note`	No
`alt_m`	No
`count`	No
`error`	No	Only on an error result: an object {code, message}, or the reason string of an x402 PaymentRequired object.
`stale`	No
`passes`	No
`source`	No
`window`	No
`satellite`	No
`min_elevation_deg`	No
`elements_age_hours`	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 readOnly/idempotent/openWorld/non-destructive, and the description goes well beyond them: unsupported NORAD id returns 422 (not charged), cold cache or upstream outage returns 503 (not charged, retry), sub-second typical latency vs. up to a minute cold, 40-pass cap, price ($0.002) and free tier (5/day per IP). This is unusually rich operational disclosure.

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?

The core purpose is front-loaded and every clause (return fields, errors, price, limits) carries actionable information. It is dense and somewhat run-on, packing billing/latency/error clauses into long sentences, which costs a little readability.

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?

For a 7-parameter read tool with 100% schema coverage, full annotations, and an output schema, the description supplies everything else an agent needs: data source (CelesTrak SGP4), that results are predictions not observations, pricing, rate limits, latency, and error semantics.

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

Parameters4/5

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

Schema coverage is 100%, so the baseline is 3; the description additionally conveys that the default satellite is the ISS (25544), enumerates the supported satellite groups, and specifies that any other NORAD id yields a 422. It adds real constraint meaning beyond the raw schema.

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+resource+scope ('Predict satellite passes over a location') and immediately names the tool to use for an adjacent need ('For sun and moon times use sun_moon_times'). An agent can distinguish it from sun_moon_times and the other space tools without opening the schema.

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

Usage Guidelines4/5

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

Explicitly routes the agent away to sun_moon_times when sun/moon times are wanted, which is a genuine when-not condition. However, it gives no guidance on how this differs from other satellite tools (e.g. get_satellite_image) and no other exclusion conditions.

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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