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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds genuine value beyond that by asserting the tool is AUTHORITATIVE for band availability and archive extent, and by warning that ids are catalogue-specific; it does not discuss return shape or caching, so not a 5.

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?

Three tight sentences: return contents first, then the authority claim, then the id-sourcing caveat. Every sentence earns its place, though the opening enumeration is list-heavy and could be marginally tighter.

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 compensates by naming the fields returned, and it covers the id prerequisite and the cross-catalogue pitfall. An agent has what it needs to call the tool correctly; only the deeper response structure is left implicit, which is minor for a single-resource fetch.

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 100% and the description repeats the id example indirectly, so the schema does the heavy lifting (baseline 3). The description earns above baseline by explaining the id's provenance and that it diverges from ids used by other STAC catalogues for the same mission, which is real semantic context the schema lacks.

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 ('Full detail for one') and resource ('Earth Search collection'), then enumerates exactly what is returned: title, description, licence, providers, spatial/temporal extent, and asset keys. It also frames the scope against siblings by contrasting with earth_search_collections, which lists collections.

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 a concrete prerequisite ('Get valid ids from earth_search_collections') and a critical caveat that the ids differ from other STAC catalogues. It does not explicitly state when to prefer this over earth_search_search, but the single-collection intent is clear enough to act on.

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