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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true), so the bar is lower. The description adds useful output context — 'categorized and sized images' — telling the agent the gallery is richer than a flat photo list. It stops short of noting rate limits or pagination, but even with an output schema present this adds real value.

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 compact clauses, front-loaded with the action and resource, followed immediately by the sibling differentiation and the prerequisite. 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?

Output schema exists so return values needn't be spelled out, and annotations cover safety. The description supplies the identifying-purpose, sibling differentiation, and place-id sourcing — everything needed to call it correctly. Only pagination/volume expectations 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 coverage is 100%, so place_id, lang, and country are fully documented in the schema and baseline is 3. The description adds provenance for the required place_id by pointing to apple_maps_place/apple_maps_search, which is genuine guidance beyond the schema's format-only description.

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 ('Fetch') and resource ('Apple Maps photo gallery for a place'), and explicitly contrasts with the sibling apple_maps_place ('shows at most 20 photos'). An agent can distinguish this from other apple_maps_* tools without opening a schema.

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 — use this when you need the complete gallery beyond the 20-photo cap — and names apple_maps_place / apple_maps_search as the source of the required place ID. It doesn't state an explicit 'when not to use' beyond the implied 20-photo threshold, so it falls just short of 5.

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