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

With no annotations, the description must carry the behavioral load. 'Check' implies a safe read-only lookup and 'PRO' signals it is a paid/authenticated tier, but it doesn't confirm the boolean return, failure behavior for malformed dates, or whether authentication is mandatory.

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 sentences with the core operation front-loaded after a terse tier marker. 'PRO.' is the only questionable token, since it is unexplained shorthand, but it earns space by signaling paid access.

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 two-parameter read tool with no output schema, the essentials of input format and scope are present. It still omits what the response looks like (presumably a boolean) and what happens to dates outside the AU list or invalid input, which matters for correct invocation.

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%: the undocumented parameter is 'date', and the description supplies exactly the missing contract, YYYY-MM-DD format. The access_token requirement is covered by the schema's own description, so the gap is effectively closed.

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 verb and resource: check a date against the AU holiday list, with the accepted date format named. The AU scope implicitly separates it from by_state and next_holidays, but the distinction is never made explicit, so an agent must infer it.

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 instead of by_state or next_holidays, and no prerequisites beyond the 'PRO' hint. The sibling names suggest a national-level lookup versus state-specific or upcoming-holiday alternatives, but the description never states that.

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