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

With no annotations, the description carries the full burden; it does disclose two useful traits beyond the schema — the data source (latest RBA rate) and that this is a subscriber/PRO feature, which explains the access_token parameter. It says nothing about failure behavior for unlisted currencies, rate staleness/timestamping, or what a successful response returns.

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?

A single tight sentence with the core operation front-loaded and the '(A$1 = X)' direction note earning its place. The leading 'PRO' tag is terse and slightly cryptic without context, but the overall size is appropriate.

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 3-parameter tool with no output schema, no annotations, and low schema coverage, the description leaves too much open: which currencies are 'listed', what the response contains (converted amount, rate used), and what the PRO/access_token requirement means in practice. It is not sufficient on its own for reliable 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 description coverage is only 33%, with just access_token documented, so the description must compensate and largely does not. 'Listed currency' gestures at an allowed-value set for the currency parameter but never enumerates or explains it, and it adds nothing about amount_aud beyond the name.

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 verb and resource: convert AUD into another currency using the latest RBA rate. The '(A$1 = X)' clause pins down the conversion direction. It does not distinguish this from siblings fx_rate and fx_table, so an agent can't tell why it should pick convert over a raw rate lookup.

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 relative to fx_rate or fx_table, which are the obvious alternatives. The only hints are indirect: 'PRO' suggests a paid-tier requirement and 'listed currency' implies a restricted currency set, but neither is explained.

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