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

With only openWorldHint annotation, the description adds useful behavioral context: it returns a list with names/coordinates/distribution, covers specific POI types, and clarifies billing is per region × POI type, not per row. It does not describe pagination or output format, but an output schema exists.

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 concise and front-loaded: purpose in the first sentence, exclusions in the second, examples in the third, followed by a structured pricing note. Every sentence earns its place with 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?

The description covers scope, exclusions, typical queries, and billing, which is sufficient given the output schema. It could mention version fallback behavior, but the version parameter is already documented in the schema.

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?

The input schema already provides 100% parameter descriptions, including examples and extraction rules. The description reinforces the single-region requirement and typical usage, but adds little semantic detail beyond what the schema already states.

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 clearly states the tool queries a list of transport POI details (name, coordinates, distribution) for a specific city/district, and enumerates covered types (airport, train, metro, bus, parking). It differentiates from sibling count tools by explicitly saying it does not answer count questions like 'how many metro stations'.

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 specifies when to use (requires a clear city/district name, for POI detail lists) and provides typical question patterns. It explicitly names the alternative gov_data_poi_amenity for counts and mentions transport operation indicators for speed/throughput, giving clear when-not-to-use guidance.

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