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

Annotations already establish that the tool is read-only, idempotent, and non-destructive. The description adds non-obvious behavioral context: this is a BYOK tool that calls an external ABR web service, so there is no platform-managed key. It also says results are ranked, though it does not explain ranking details, rate limits, or error behavior.

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 compact and front-loaded: it starts with the critical BYOK caveat, states the core action, explains the key requirement with a registration link, and finishes with a concrete example. Every sentence 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 four-parameter tool with rich schema coverage and safety annotations, the description plus schema cover the prerequisite, required parameters, optional filtering, and the general result type. The main missing contextual items are more detail about the return fields and an explicit comparison against abn_lookup, so it is not fully complete.

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%, and each parameter already has a useful description, so the baseline applies. The description's example demonstrates the required name and _apiKey combination, which adds a little clarity, but it does not add substantial meaning beyond what the schema already provides.

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 names a specific resource (Australian Business Register) and a concrete verb (search by entity/business name and return ranked ABN matches), and it includes a working example. It is not a tautology and is clear enough to know what the tool does, but it does not explicitly differentiate it from the sibling abn_lookup tool.

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 clearly states the prerequisite: the caller must provide their own ABR web-services GUID and register for a key. However, it does not explicitly say when to use this tool instead of alternatives such as abn_lookup, nor does it give any when-not-to-use guidance.

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