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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds meaningful behavioral context: the result is the "complete live value space" and includes per-value community counts, telling the agent this is an authoritative, uncached reference lookup rather than a sampled list.

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, zero filler, with the scope of the returned value space front-loaded and the usage instruction last. 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?

For a parameterless lookup with an output schema present, the description supplies everything needed: what is returned, that it is the full live value space, and that it should be called before greystar_search. No gaps remain.

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 tool takes no parameters (empty schema, 100% coverage vacuously), so the baseline is 4. There is nothing for the description to disambiguate, and it correctly implies a parameterless call.

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 a specific verb (List) and a precise resource (market area, neighborhood, city, state, country accepted by greystar_search filters), plus the count of communities per value. An agent can immediately distinguish this from greystar_search and greystar_locations without opening a 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?

"Call this first to get valid filter values" gives an explicit when-to-use directive tied to greystar_search, which is genuinely actionable. It does not name a when-not condition or an alternative lookup tool (e.g. greystar_locations), so it stops short of a 5.

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