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

Annotations already establish readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds useful rendering context (equirectangular graticule, centerline plus shaded band of a given degree width) and a cost note, but says nothing about output format behavior beyond that, e.g. that json is the default format.

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 tight sentences plus metadata tags; the rendering substance (projection, centerline, band width) is front-loaded with 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 complex tool with 7 parameters, nested objects, and only 29% schema coverage, the description leaves major gaps: the relationship between the required `path` and optional `centerlinePoints`, item count limits (min 2 / max 500), and the visual/style controls. An output schema exists so return values need not be explained, but input-side completeness is still weak.

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 29% on a 7-parameter tool. The description clarifies the intent of the band width and the notion of a supplied track, but it never explains the distinction between `path` and `centerlinePoints` (both lat/long arrays), nor the size/width/height/theme/format render options.

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: renders an equirectangular world map with centerline and a shaded band, which is a distinct rendering output versus computing siblings like astroway_geo_eclipse_analysis. It does not explicitly name or rule out those siblings, but the rendering scope is clear from the wording.

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 'caller-supplied eclipse track' implies the caller must already have the track data rather than computing it, but there is no explicit when-to-use, when-not-to-use, or pointer to the sibling that produces eclipse tracks (e.g. astroway_calendar_eclipses or astroway_geo_eclipse_analysis). An agent has to infer the precondition.

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