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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and closed-world scope, so the safety profile is fully covered. The description still adds real information with 'published listings' (result scope excludes unpublished inventory) and 'No arguments', but says nothing about cost, caching, or freshness of the counts, which matters for an aggregate call.

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 short sentences, no filler, and the return contents are front-loaded before the calling convention. Every clause earns its place.

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 an output schema present and no inputs, the description need not explain return shapes, and it covers the dimensions the counts span. The one gap is that it never connects the returned filter values to the sibling search tool that consumes them.

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?

Zero parameters, so the baseline is 4. 'No arguments' usefully confirms the agent should call it bare rather than attempting to pass filters.

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?

States concretely what the tool returns: aggregate counts of published listings broken down by country, type, city, price range, plus the set of valid filter values. This is specific enough that an agent can tell it apart from a search tool, though it never names search_homes or explains the relationship.

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?

There is no explicit when-to-use or when-not-to-use guidance. The phrase 'valid filter values' hints that this is a discovery/seed call before searching, but the agent must infer that and infer that search_homes is the consumer of those values.

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