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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so safety and repeatability are covered. The description's added value is scope of content, including that refusal rates are benchmarked against all nationalities, which is genuinely useful context an agent could not infer. It says nothing about data freshness, what happens for a country code with no profile, or the response shape.

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 front-loaded sentence that opens with the resource and then lists the returned data blocks in a scannable series. Every clause names a distinct field, so nothing is padding. It is a long run-on list, which costs a little readability, but the density is justified.

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 one parameter, full schema coverage and no output schema, the description carries the burden of describing return values, and it does so across all four data categories. An agent can decide whether to call it from this text alone. Minor gaps remain around output format and edge-case behavior for unrecognized country codes.

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%: the single 'country' parameter documents the ISO 3166-1 two-letter pattern and gives an example ('PH'). The description reinforces this by framing the lookup as 'one nationality' and 'its passport', confirming the parameter is a passport country rather than residence. That is mild corroboration, not new semantics, so 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?

Names the resource precisely ('Australian visa figures for one nationality') and enumerates the four data blocks returned: visitor visa type, working holiday eligibility plus age limit, refusal rate versus all nationalities, and processing times by visa. That is far more specific than the title alone. It stops short of 5 because it never distinguishes itself from siblings that overlap on the same data, notably get_processing_times and get_visa_fees.

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?

Usage is only implied: the phrase 'for one nationality' signals a per-country profile lookup, and the field list implies this is the aggregate view rather than a single-metric call. There is no explicit statement of when to prefer this over get_processing_times or get_visa_fees, even though those siblings plainly overlap on processing times and visa data. No prerequisites or exclusions are given.

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