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

With no annotations, the description does add useful behavioral constraints: it discloses a subscriber/PRO access requirement, a fixed 50 km radius, and an NSW geographic restriction. It does not disclose return contents, pagination, error behavior, or whether the access_token is mandatory in practice.

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?

It is brief and front-loads the key constraint, but the fragment 'PRO. AQ sites' is not self-explanatory and reads as unexplained jargon rather than efficient communication.

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 tool with no annotations and no output schema, the description is too thin: it omits what 'AQ' means, what results look like, authentication expectations beyond the schema, and any behavioral caveats around the fixed radius or NSW scope.

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 coverage is 50%: access_token is documented in the schema, but postcode has no description there. The description compensates partially by implying postcode must be an NSW postcode tied to a 50 km radius, but it does not specify format, validation, or what happens for non-NSW postcodes.

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?

It states a specific operation (find sites within 50 km of a postcode), which is distinguishable from the generic siblings sites and site_search. However, the abbreviation 'AQ sites' and the leading 'PRO.' fragment leave the resource ambiguous; an agent cannot be fully sure what 'AQ' refers to without outside knowledge.

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 guidance on when to use this tool over site_search or sites, and no stated exclusions or prerequisites beyond the cryptic 'PRO.' prefix. The agent must infer that proximity-to-postcode is the selecting condition.

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