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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds useful behavioral context such as the data source (National Public Toilet Map), sorting by distance, the fields returned, and the fallback behavior when no toilets are within radius. This goes beyond the annotations and helps set expectations.

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?

The description is efficiently structured: first sentence states the core purpose, followed by use-case examples and return details. The second paragraph addresses a key ambiguity around location handling. No redundant or filler content exists; every sentence serves a purpose.

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?

The tool is relatively simple with no output schema, but the description covers return fields, sorting, and filtering behavior. It also addresses the common 'near me' scenario. Minor gaps exist such as error handling for invalid coordinates or exact pagination, but overall this is sufficiently complete for effective use.

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 parameters are already documented. The description adds extra semantic value by explaining how latitude/longitude should be derived from user context or conversation, and notes default values for limit and radius. This supplements the schema descriptions meaningfully.

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 opens with a specific verb and resource: 'Find the nearest PUBLIC TOILETS to a location'. It clearly distinguishes from sibling tools like search_campsites or get_campsite_details by focusing on toilets. The example queries further clarify the tool's purpose.

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?

The description explicitly states when to use the tool ('Use this for questions like...') and provides concrete example phrases. It also gives guidance on how to handle 'near me' queries, either passing known context or asking for location. It lacks explicit exclusions or comparisons to alternatives, but the context is clear enough for correct selection.

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