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

No annotations are provided, so the description carries the full burden, but it does contribute real behavioral context: the data source (RBA), freshness ("Latest"), and cost ("FREE"). It stops short of disclosing return shape, update cadence, base-vs-target direction, and error behavior, which matter for a data-retrieval tool with zero annotation coverage.

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 very short fragments, no filler beyond the leading "FREE." marketing token, and the resource is stated immediately. Slightly front-loaded with cost rather than function, but essentially no waste.

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 one-parameter tool with no output schema and no annotations, the description should at minimum say what comes back and how it differs from fx_table and convert. It leaves the return shape (single number vs. column) and sibling boundary unresolved, which is the core decision an agent must make.

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 0%, so the description must compensate, and it partially does by giving concrete code examples (USD, CNY, JPY, EUR, GBP) that establish the expected 3-letter currency-code format. It does not clarify whether the supplied currency is the target or the base relative to AUD, nor what happens if AUD is passed.

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 identifies the resource as the latest RBA AUD exchange rate and implies a lookup verb, so the general intent is graspable. However, "column" is ambiguous (single rate vs. a series) and nothing distinguishes this from siblings convert or fx_table, leaving the agent to infer the boundary.

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 at all: no mention of when to prefer this over convert (likely for converted amounts) or fx_table (likely for the full table). The only usage-adjacent signal is "FREE", which speaks to cost, not routing.

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