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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the shape of the payload (places with addresses, hours, photos), but with an output schema present that content is largely redundant and it omits any latency, coverage, or rate-limit caveats.

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 sentences, both front-loaded: the action and its inputs first, then sibling routing. No filler, no repetition of schema content.

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 an output schema, full parameter descriptions, and read-only/open-world annotations, the description covers everything needed to select and call the tool correctly. Its job of routing between the guide tools is fully discharged.

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 lang, country, and guide_id are fully documented in the schema itself. The description references guide_id and locale but adds no format or sourcing detail beyond what the schema provides, making the baseline 3 appropriate.

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 and resource: fetch one curated Apple Guide by guide_id and locale. It also lists the returned payload types (metadata, places, addresses, coordinates, hours, photos), which lets an agent distinguish this detail-fetch from the sibling browse/lookup tools.

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?

Explicitly names the alternatives and their roles: apple_maps_guides for browsing, apple_maps_guides_lookup for finding by name, apple_maps_guides_publisher for publisher details. Combined with the required guide_id in the first sentence, the selection condition for this tool is unambiguous.

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