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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: the 30+ transaction minimum, the default exclusion of whole-building leases and land deals, and the 12-month median window. These are exactly the kind of filtering behaviors an agent needs to know to interpret results correctly.

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 dense with useful information. The first sentence front-loads the core purpose and user intents; the second adds the critical filtering caveats. No wasted words, no repetition of schema details.

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 ranking tool with no output schema, the description covers the key decision factors: what metric is used, what the default scope is, and the minimum transaction threshold. It doesn't describe the return format or whether results include the median values, but the absence of an output schema and the read-only annotation make this a minor gap rather than a critical one.

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 50%, with metric and propertyClass having descriptions. The description adds meaning by explaining the default propertyClass behavior (residential only) and clarifying that metric values map to 'sale prices' or 'annual rents'. It doesn't detail the limit or order parameters, but those are self-explanatory from their names and enums, so the description compensates well for the coverage gap.

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 states a specific verb ('rank'), a resource ('communities'), and the two ranking metrics (12-month median sale price or median annual rent). It also explicitly ties the tool to user intents like 'cheapest areas' and 'most expensive communities', which makes its purpose unmistakable and distinguishes it from siblings like rank_buildings.

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 gives clear context on when to use this tool: when the user wants the direct answer to cheapest/most expensive/most affordable areas. It also explains the default behavior (residential classes only without propertyClass filter) and the 30+ transaction threshold, which helps an agent decide whether this tool is appropriate versus alternatives like get_market_overview or rank_buildings.

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