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

With no annotations, the description carries the full burden. It discloses that the tool costs 0¢ per call, which is a behavioral trait, and states the content type (SA4 regions grouped by state). It doesn't describe the response structure or any side effects, but for a zero-parameter reference tool this is sufficient and adds value beyond the name.

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?

The description is brief and front-loaded with the core purpose. The price is mentioned twice ('0c.' and 'Price: 0¢ per call'), which is slightly redundant but does not detract significantly. Overall, it is efficient and focused.

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?

Given the tool has zero parameters and an output schema exists, the description adequately covers what an agent needs: it states the purpose (reference for search parameters) and cost. It doesn't list alternative tools explicitly, but the reference to 'search' is sufficient in context.

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 has no parameters, so the baseline is 4. The description goes beyond the name by explaining that the output is the set of accepted values for search parameters, which clarifies the tool's role without any parameter documentation needed.

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 clearly states that this tool returns SA4 regions grouped by state, and specifies that these are the accepted values for the `states` / `regions` parameters on search. This is a specific verb-resource pairing that distinguishes it from the many sibling tools, especially other suburbs_finder_* tools.

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 explicitly mentions that the values are accepted by `states`/`regions` on search, which tells the agent when to use this tool (when needing valid region/state values). It doesn't explicitly contrast with alternatives like suburbs_finder_fields or suburbs_finder_search, but the context is clear enough to route the agent correctly.

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