NASA Trek map layers (Mars, Moon, Vesta)

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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, so the safety profile is covered. The description adds genuinely new operational context: no API key is required, and it names the payload fields returned (layer ID, mission, instrument, WMTS endpoint) — useful for a tool with no output schema.

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; purpose and scope come first, the downstream handoff second. No filler or repetition of the title.

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, the description carries return-value burden and does so by listing the returned fields and naming the tool that consumes them. Coverage of bodies, auth, and pipeline role is solid; only edge behaviors (pagination limits beyond the schema) are left implicit.

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 100%, so every parameter (body enum, limit range, search, projection) is already documented. The description mentions the three bodies and layer types but adds no format or matching semantics for search or projection beyond 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 (search) plus the resource (map layer catalogs of Mars/Moon/Vesta Trek) and the content type (mosaics, colour hillshades, OGC WMTS tiles). It also explicitly distinguishes itself from the sibling nasa_trek_tile by naming it as the consumer of the returned layer IDs.

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?

Gives clear usage context: discover layers here, then feed the returned IDs to nasa_trek_tile. It does not state when to avoid the tool or how search terms map to the catalog, but the workflow positioning is unambiguous.

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