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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so safety is covered. The description adds real behavioral value beyond that: it says the response includes the tile URL plus the tile's geographic bounds and the resolved date (important because the date may be defaulted), and that zoom is capped at the layer's deepest level. No auth/rate-limit notes, but GIBS is public so that gap is minor.

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 sentences, front-loaded with a concrete example of the user request it answers, then the two input paths, then the return payload. No filler and no restating 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 steps in and names what is returned (URL, tile bounds, resolved date), which is exactly what an agent needs to decide it can display or download imagery. Combined with the fully documented 8-parameter schema, nothing material is missing for correct invocation.

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 the baseline is 3. The description still earns an extra point by clarifying the mutually exclusive input strategies (lat/lon + zoom vs tile_row/tile_col) and by implying the layer/date/zoom interplay, which is the main semantic decision an agent must make when invoking the tool.

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?

The description states a specific verb and resource — it builds a ready-to-fetch NASA GIBS image tile URL — and immediately shows the concrete outcome with a natural-language example ('satellite image of Los Angeles on 2026-09-10'). It is clearly distinguishable from its GIBS siblings (gibs_layer_info, gibs_list_layers) which inspect/ enumerate layers rather than produce a tile URL.

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?

It gives clear context for use and explicitly routes between two input modes: supply latitude/longitude plus zoom to have the row/column computed, or supply tile_row/tile_col if already known. What's missing is any explicit when-not or pointer to the sibling tools (e.g. use gibs_list_layers first to find a layer id).

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