satellite_image

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

With no annotations, the description carries the burden and does well: it discloses cost ($0.013 USDC per call), latency (p99 8000ms), return format (base64 JPEG), and provenance. It doesn't state auth/payment prerequisites or error behavior, but the operational traits it does expose (cost, latency, output) are exactly what an agent needs before calling.

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?

Front-loaded with purpose and source before the dense parameter block, and every clause carries information. The parameter section is a long run-on sentence with heavy parenthetical nesting, which slightly hurts scannability but wastes no words.

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 9-param, zero-required, no-annotation, no-output-schema tool, the description covers input modes, defaults, output format, cost, and latency — nearly everything an agent needs. It leaves unresolved which location mode wins if more than one is supplied and doesn't guide layer selection, minor gaps against an otherwise thorough definition.

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 coverage is only 11%, so the description must compensate — and it does: it explains the three mutually exclusive location modes (place / bbox / lat+lon+radius_km), the bbox ordering [min_lat, min_lon, max_lat, max_lon], the date format and 'yesterday' default, the layer options, and width/height ranges and defaults. This adds substantial meaning beyond the bare 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+resource: 'Daily true-color satellite image of any area from NASA GIBS,' naming the exact data sources (MODIS Terra/Aqua, VIIRS), resolution (~250 m/pixel), and output form (base64 JPEG with coastlines). An agent can distinguish this from sibling satellite_compare by the single-image, single-day scope.

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?

'Useful to see clouds, smoke, snow, floods or fires on a given day' gives concrete use-case context for when to reach for it. It stops short of naming exclusions or pointing at the sibling satellite_compare for multi-date/compare workflows, so usage routing is clear but not exhaustive.

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