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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the agent knows this is a safe, self-contained lookup. The description adds only that the answer is about service-area coverage; it does not say what the response looks like (boolean vs. list of served areas) or how to interpret a negative result, so the behavioral picture is only partly filled in.

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, with the core question front-loaded and the input formats second. The list of place types largely duplicates the schema field, so a few words are not strictly earning their 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 two-parameter, read-only lookup with full schema coverage and no output schema, the description supplies enough to invoke it correctly. The main gap is that the shape of the answer — a yes/no coverage verdict — is left implicit rather than stated.

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 100%, so both parameters are already documented and the baseline is 3. The description repeats the accepted place formats and notably adds 'county', which the schema's place description omits — a small enrichment, but also a slight mismatch with the declared input contract.

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 frames a specific question about a specific resource: whether a given brokerage's service area covers a given place. That is distinguishable from find_brokerages (discovery) and about_brokerage (profile lookup) without opening a schema, though it never names those siblings explicitly.

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?

Usage is implied by the question framing — call it when you need to verify coverage before booking or referring. There is no explicit when-to-use/when-not-to-use guidance and no pointer to the sibling tools that would supply brokerage_id or handle the follow-up action.

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