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 what the result contains (address, hours, BOPIS/curbside/same-day flags), which is useful context, but since an output schema exists that material is partly redundant and no rate limits, result caps, or coverage caveats are disclosed.

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?

One sentence, front-loaded with the primary purpose and the returned fields, with zero filler. Nothing could be trimmed without losing information.

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?

For a read-only, open-world proximity lookup with full schema coverage and an output schema documenting the return shape, the description supplies everything needed to call it correctly. Only minor gaps remain, such as coverage area or whether results are capped by the limit default.

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% and each parameter (limit, radius, latitude, longitude) carries its own range and default documentation, so the schema does the heavy lifting. The description's only parameter hint is 'near a coordinate', adding nothing beyond the required lat/long already specified — baseline 3 is 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?

The description gives a specific verb-resource pair ('Sephora physical store locations') and scopes it to a coordinate-proximity lookup, which cleanly separates it from the product/brand/category siblings in the sephora_* family. It stops short of naming any sibling it should not be confused with, but no near-identical store sibling exists, so the resource is unambiguous.

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?

Implicit usage is conveyed by 'near a coordinate' — an agent can infer this is the geospatial store-lookup tool rather than a search tool. However there is no explicit when-to-use/when-not statement and no mention of whether a geocoded address must be resolved first (e.g. via a geocoding tool).

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