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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely useful context beyond that: it is a snapshot of the latest reading only, lists the metrics returned (index, period, annual % change), and discloses a 1¢ per-call cost, which is a real operational fact not present in annotations. It stops short of stating rate limits, whether all cities are always returned, or caching 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?

Two short, front-loaded sentences: the first defines the resource and its outputs, the second states cost. No filler or redundant restatement of the title. The pricing line is compact and earns its place for an agent deciding whether to spend a call.

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?

With only two optional parameters at full schema coverage and no output schema, the description does a reasonable job by naming the returned fields. However, for a tool sitting in a dense cluster of CPI and economics siblings, it omits the disambiguation an agent needs, leaving the selection decision under-informed.

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 the item parameter's enumeration of 26 series plus the frequency options are fully documented in the schema. The description adds nothing about how item or frequency affect the result (e.g. whether monthly data is available for all items), so it rests at the baseline for fully-described parameters.

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 resource (latest CPI) with explicit scope: Australia plus each capital city, with index, period and annual % change as outputs. It does not distinguish itself from the sibling tools economics_cpi, economics_cpi_adjust, or economics_series, so an agent cannot tell from the description alone which of these to prefer for a given CPI need.

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 mention of when this is inappropriate, and no pointer to the clearly related siblings (economics_cpi, economics_cpi_series-like tools such as economics_series) for historical ranges. The word 'latest' implies a recency constraint but the agent must infer that history requires another tool.

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