weather_satellite_now

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

With no annotations, the description carries the full behavioral burden and does a lot: it declares 認証不要 (no auth), warns that band is silently ignored for non-Himawari sources, and explains that size is a compatibility parameter whose actual value must be read from structuredContent.size_px. It also specifies that supplying lat/lon/place switches the output to a 1500×880 composite panel — a real behavioral distinction, though error handling and latency are unaddressed.

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?

Purpose is front-loaded in a single sentence, followed by concrete query examples, then an Args block where each entry carries non-redundant information. It is long, but nearly every line adds constraint or alias knowledge an agent could not infer, so the length is justified rather than padded.

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 tool with six parameters, zero annotation coverage, no output schema, and 0% schema descriptions, the definition supplies almost everything needed: auth status, per-parameter semantics, cross-parameter interaction, and a hint that a link is returned ("回答時はこのリンクをそのまま提示してください"). Only the response payload shape and failure behavior remain underspecified.

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%, and the description compensates fully by documenting all six parameters: satellite (with defaults and a long list of accepted aliases such as "goes18", "fy4b", "gk2a"), band (with enumerated values plus legacy aliases "1d"/"vis"/"ir"/"wv"), size (flagged as a compatibility arg), and lat/lon/place with their combined effect. This is meaning well beyond the bare type declarations in the schema.

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 and resource — returning real-time actual imagery of the world's weather observation satellites — which clearly separates it from status-oriented siblings like satellite_status or constellation_now. It does not, however, name any sibling explicitly, so the differentiation is inferential rather than stated.

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 three example queries ("ひまわり9号の最新画像", "気象衛星の今の雲画像", "ひまわりの赤外線画像") effectively show when to reach for this tool, and the description adds explicit usage constraints (band is ignored for non-Himawari satellites, lat/lon apply only to Himawari-9). It stops short of naming a competing tool or stating when not to use it.

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