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

With no annotations, the description carries the full burden. It flags 'PRO' (a paid tier) but never says that a subscriber access_token is required for the call to succeed, nor whether results are exact/substring matches, capped, or paginated. The schema's token hint is the only auth signal, and it lives outside the description.

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 clauses with the operation front-loaded; nothing is wasted. The 'PRO.' prefix is terse to the point of ambiguity — it reads as a tier marker but is never expanded, so a small deduction.

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?

No output schema exists, so the description should describe what comes back (site objects? IDs? count?) and what an empty match yields; it says none of that. For a search tool with an undocumented required param and no annotations, this is under-specified.

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 inline but 'keyword' is a bare string in the schema. The description compensates by telling the agent the keyword matches either a site name or a region, which is real added semantics. It still says nothing about matching behavior or partial terms.

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 and resource: 'Find NSW AQ sites by name/region keyword.' The scope (NSW air-quality sites) and match dimension (name/region) are clear. It does not explicitly distinguish itself from the sibling 'sites' (list all) or 'near_postcode' (spatial search), so it stops short of a 5.

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 when-to-use guidance, no exclusion, and no reference to the obvious alternatives 'near_postcode' and 'sites'. An agent must infer that keyword lookup is the right path instead of a postcode or full listing.

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