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

With no annotations, the description carries the full behavioral burden and discloses almost nothing: it hints at a read of a 'latest' snapshot but not whether it is cached, how often the RBA table refreshes, what columns a 'full row' contains, or that access requires a paid subscription. Auth is only implied by the word 'PRO' and the access_token parameter.

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?

It is very short and front-loaded, but the compression goes too far: 'PRO' and 'F11.1' are unexplained abbreviations rather than useful shorthand. Brevity here reads as under-specification rather than economy.

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 no annotations and no output schema, the description must explain what is returned and under what conditions; instead it offers a single cryptic clause. An agent would not know the currency coverage, row shape, or freshness guarantees of the result.

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?

There is a single parameter with 100% schema description coverage ('Subscriber token from /success (or Authorization: Bearer)'), so the schema already documents it fully. The description adds no additional meaning about the token or optionality, so the baseline 3 applies.

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 names a resource ("Latest full RBA F11.1 FX row") but no verb, and the jargon ("PRO", "F11.1") assumes domain knowledge the agent may not have. It does not differentiate from the sibling fx_rate, which plausibly returns overlapping FX data, so an agent cannot confidently choose between them.

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 statement of when to use this tool versus fx_rate or convert, and no prerequisites or exclusions are given. The only implied guidance is the "PRO" prefix, which is not explained anywhere in the description.

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