Calculate the real geometric orientation, altitude, and horizon status of the Big Dipper for any given latitude, longitude, and datetime.
按每次请求的经纬度计算真实北斗七星几何方位/高度与地平线状态；没有默认城市。
| Name | Required | Description | Default |
|---|---|---|---|
| datetime | Yes | ISO 8601; naive times use input_timezone; chart clock explicitly converts to Beijing civil time. | |
| observer | Yes | ||
| input_timezone | No | Asia/Shanghai |
Changes observed during successful MCP inspections.
v0.3.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered by structured data. The description adds that computation is driven strictly by request-supplied coordinates with no default city, which tells the agent omission of location will not silently succeed with a fallback. It says nothing about precision, ephemeris source, or performance.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single tightly written sentence with the core action front-loaded and the scope caveat attached. Nothing is redundant, though it is terse enough that the omitted details (units, return shape) feel like truncation rather than deliberate brevity.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema and no description of the returned values (azimuth/altitude units, horizon-state vocabulary), the agent cannot predict the response shape. Annotations cover the safety profile and the input constraint is stated, but for a coordinate-driven astronomy computation with an underspecified nested observer object, more behavioral detail would be warranted.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 33%: only 'datetime' is documented, while the nested observer fields (latitude, longitude, label, elevation_m) and input_timezone carry no descriptions. The description partly compensates by stating coordinates must be provided per request (no default city), but it never clarifies label/elevation_m meaning or timezone handling, leaving most parameters unexplained in both places.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names a specific verb/resource: computing real Big Dipper geometric azimuth/altitude and horizon status. It also states a scope constraint ('per-request lat/long, no default city') that distinguishes it from chart tools like get_qimen_chart that likely accept defaults. It never names a sibling explicitly, so differentiation is by domain inference rather than direct routing.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no when-to-use/when-not guidance and no alternative tool is named. The phrase '没有默认城市' hints that coordinates must always be supplied, but that is a constraint on inputs, not guidance about which tool to pick for a given task.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.