Fetch NASA's Astronomy Picture of the Day for today or a chosen date. Provide a date to get that day's image; requires a NASA API key.
今日（または指定日）の NASA の今日の天文写真(APOD)を返す。NASA_API_KEY が必要。
| Name | Required | Description | Default |
|---|---|---|---|
| date | No |
Changes observed during successful MCP inspections.
v0.25.2Output schema / (root)Previous value: -{
- "properties": {
- "result": {
- "title": "Result",
- "type": "string"
- }
- },
- "required": [
- "result"
- ],
- "title": "_nasa_apodOutput",
- "type": "object"
-}New value: +nullv0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It usefully discloses a prerequisite (NASA_API_KEY が必要), which is real behavioral context, but says nothing about rate limits, error behavior, or response shape for a network-backed read.
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?
Two short sentences, front-loaded with the core purpose and followed by the auth prerequisite. No filler.
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?
For a single-parameter read tool this is nearly sufficient, but with no output schema and no annotations, the missing date format and any hint about what the response contains (image URL, title, explanation) leave a small but real gap.
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 0%, so the description must compensate. It conveys that the date is optional and defaults to today's picture ('今日（または指定日）'), adding genuine semantics, but it omits the expected date format (e.g. YYYY-MM-DD), which is the key detail an agent needs.
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?
States a specific verb ('返す' / returns) and a specific resource (NASA's Astronomy Picture of the Day), plus the scope (today or a specified date). It is clearly distinguishable from siblings like astronomy_news or search_space_images, though it does not explicitly name any sibling to route against.
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?
The phrase '今日（または指定日）' implies that the date parameter is optional and that the tool is the right choice when you want the APOD for a particular day, but there is no explicit when-to-use/when-not guidance or named alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.