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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds the underlying data source ("Park & Keep airport parking index") and confines scope to European airports, which is useful provenance, but says nothing about data freshness, coverage gaps, or how results are returned.

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?

Front-loaded with the usage trigger, then metrics, then example phrasings — a sensible order with little wasted text. The metric enumeration and three-language phrase list are somewhat long for a single-parameter tool, but each element serves intent matching.

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 no output schema, the description carries the burden of telling the agent what comes back, and it does list the returned metrics qualitatively. It stops short of describing the response shape, units for distance, or handling of an unknown airport, which keeps it from being fully complete.

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?

Only one parameter, and schema description coverage is 100% — the schema already documents that it accepts an IATA code or an airport/city name with examples ("BRU", "Charleroi", "Málaga"). The description adds no disambiguation guidance for ambiguous city names or format normalization, so the baseline of 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 names a specific verb+resource (parking market snapshot for a European airport) and enumerates the exact metrics returned: competitor count, shuttle/valet/covered share, median and shortest distance, and count with published prices. That metric set implicitly separates it from airport_parking_options and airport_price_snapshot. It loses a point only because it never names the sibling tools to make the boundary explicit.

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 gives an explicit trigger ("Use this when a car park operator or analyst asks about the parking market around a European airport") plus three concrete example phrasings, including a non-English one, which makes intent matching easy. There is no when-not guidance and no routing to alternative tools for adjacent questions.

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