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

The annotations already declare readOnly, idempotent, and non-destructive behavior, so the bar is lower. The description adds valuable behavioral context beyond that: null means unknown, the tool fails if any property is no longer public, and units are explicit EUR/period/m². These are exactly the non-obvious runtime behaviors an agent needs.

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?

Three short sentences, each carrying essential information: core operation, unit/null semantics, and failure mode. The most important constraint is front-loaded. No filler or 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?

There is no output schema, but the description covers key return semantics: same fields, explicit units, and null meaning unknown. The failure mode is also disclosed. It lacks a bit of detail on locale behavior, but for a two-parameter comparison tool with strong annotations, this is nearly 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?

Schema description coverage is 0%, so the description must compensate. It does add meaning for the ids parameter: IDs must be 2–4, distinct, and public, and failure occurs if a property is no longer public. However, the locale parameter is never mentioned, so the description only partially compensates for the schema 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 starts with a specific verb and resource: compare 2–4 distinct public property IDs. This clearly distinguishes it from siblings like get_property (single property), search_properties (search), and get_area_statistics (area stats) without needing to open the schema.

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 implies when to use it: whenever you need to compare 2–4 public properties. However, it never explicitly names alternatives or states when not to use it, so the agent has to infer the use case from the word 'compare' and the ID-count constraints.

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