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

With no annotations, the description carries the full behavioral burden. It does usefully disclose that this is a pure checksum/algorithm check (not a live registry lookup) and that it is free, which tells the agent there is no auth or cost concern. However, it says nothing about failure behavior, error signalling, or scope limits.

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?

One short sentence with the key fact ('Free') front-loaded and no filler. It is efficient, though the brevity comes at the cost of the missing detail noted in other dimensions.

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?

An output schema exists, so return values need not be described. For a simple two-parameter validator the description is minimally sufficient, but with zero annotation coverage and zero parameter description coverage it leaves the input contract 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 description coverage is 0% across two parameters. The description mentions the ABN concept but gives no format guidance (e.g., 11 digits, spacing, string vs numeric) and never explains the 'jurisdiction' parameter or why it defaults to AU for an Australia-specific check.

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 verb ('check') and resource ('an Australian Business Number's checksum'), plus the algorithm used (ABR). The 'Australian' qualifier implicitly separates it from siblings like validate_ird and validate_nz_bank, though no sibling is named 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?

There is no statement of when to use this tool versus alternatives, no prerequisites, and no mention of what a caller should do when validation fails. The only contextual hint is the 'Free:' prefix, which signals a cost model rather than usage guidance.

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