mcp-stargazing

get_celestial_rise_set

Calculate rise and set times for a celestial object at specified coordinates, time, and timezone to plan observations.

Instructions

Calculate the rise and set times of a celestial object.

Use when: you need one object's rise/set events. Choose calendar_day for the local date containing time, or next_events for the next rise and next set after time. Do not use when: you need a continuous observing window or a complete night plan. Requires: object name, observer coordinates, time, timezone, and the intended event scope. Follow-up: get_celestial_pos for position; plan_stargazing_session for observing windows.

Args: celestial_object: Name of object (e.g. "sun", "moon", "andromeda") lon: Observer longitude in degrees lat: Observer latitude in degrees time: Date string "YYYY-MM-DD HH:MM:SS" time_zone: IANA timezone string event_scope: "calendar_day" (default) finds the events in the local calendar day containing time. "next_events" finds the next rise and next set independently, rolling into following days when needed.

Returns: Dict with keys "data", "_meta". "data" contains "rise_time" and "set_time".

Input Schema

Name	Required	Default
`lat`	Yes
`lon`	Yes
`time`	Yes
`time_zone`	Yes
`event_scope`	No	calendar_day
`celestial_object`	Yes

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.10.0Oct 28, 2026
- addedInput schema / properties / event_scope
```
Added value: +{
+  "default": "calendar_day",
+  "type": "string"
+}
```
First observedv1.0.0Jan 4, 2026

TDQS

A4.6/5.0

Behavior4/5

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

With no annotations, the description carries the full burden and does well: it explains the two event_scope behaviors (calendar-day lookup vs independent next rise/set rolling into following days), lists prerequisites, and notes return keys. Gaps remain around degenerate cases (circumpolar objects, no rise/set) and error behavior, so not a 5.

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?

Structured with labeled sections and front-loaded purpose plus when/when-not. Slight redundancy: the Args and Returns blocks largely restate schema/output-schema content, but each remains brief and harmless.

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

Completeness4/5

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

Output schema exists, so the "Returns" note is optional; parameters are fully documented and alternatives are named. Still missing edge-case behavior (objects that never rise or set, validation bounds on lat/lon), which would complete a calculation tool with no annotations.

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

Parameters5/5

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

Schema coverage is 0%, so the description must compensate and does: it gives the time format ("YYYY-MM-DD HH:MM:SS"), the IANA timezone string, degrees for lon/lat, example object names ("sun", "moon", "andromeda"), and a clear default/semantics for event_scope. This is meaningfully richer than the bare 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 and resource ("Calculate the rise and set times of a celestial object") and distinguishes itself from siblings by naming get_celestial_pos for position and plan_stargazing_session for observing windows. An agent can route to it 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 Guidelines5/5

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

Explicit "Use when" / "Do not use when" sections name the alternative (continuous observing window or complete night plan) and the required inputs. Nothing is left to inference about when this tool is the right choice.

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