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

With no annotations provided, the description carries the full burden. It discloses that it 'Returns latest period and YoY percentage', which is a useful behavioral detail about output. However, it does not explicitly state safety characteristics (e.g., read-only, no side effects) or any limitations, leaving some assumptions for the agent. The description is not misleading but is minimal in behavioral disclosure.

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 a single sentence of about 20 words, front-loaded with the core purpose and output. Every word adds value, with no fluff or repetition. It is exceptionally concise and well-structured.

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 simple tool with one parameter, no output schema, and no annotations, the description is nearly complete. It specifies the data source (ABS 6401.0), the scope, and the output (latest period and YoY percentage). The only minor gap is a lack of explicit note about the absence of side effects, but for a CPI retrieval tool that is not a significant omission. The agent can call it correctly with the given information.

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 100% as the single parameter 'region' has a description ('ABS region or 'National' (default)'). The tool description adds a mild hint about scope ('Australia or capital-city region'), but this is largely redundant with the schema. While the description does reinforce the parameter's meaning, it does not add significant new semantics beyond the schema, so a baseline score of 3 is appropriate.

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 states a specific verb ('Returns') and resource ('ABS quarterly CPI YoY change (6401.0)') and clarifies scope ('for Australia or capital-city region'). It clearly differentiates from siblings like au-abs-building-activity or au-cash-rate by focusing on CPI data, so an agent can identify its purpose without confusion.

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 provides context (Australia or capital-city region) but does not explicitly state when to use this tool versus alternatives or when not to use it. It is implied that this is the go-to for Australian CPI, but no explicit exclusions or alternative references are given. This is adequate but not proactive guidance.

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