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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the bar is low. The description still adds useful behavioral context the annotations do not: the response includes JPY prices, service limits, and explicitly 'what is not offered', which tells the agent it can use this call to rule out unsupported requests.

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 a single front-loaded sentence with no filler, verb and resource first, qualifications after. The long parenthetical service enumeration is informative for intent matching but is the one element bordering on verbose.

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 parameters and no output schema, the description carries the return-value burden and does so by naming the payload (services, JPY prices, limits, exclusions). It is complete enough to call correctly, though it does not sketch the response structure at all.

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?

The tool takes zero parameters, so the baseline is 4; there is nothing for the description to disambiguate beyond confirming it is a no-argument catalog listing.

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 gives a specific verb ('List') and resource ('the services MARU Japan Hands provides in Japan') and even enumerates the catalog contents, so an agent knows exactly what it returns. It stops short of the top score because it never distinguishes this catalog tool from siblings such as check_availability or request_service.

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 explicit when-to-use, when-not, or 'use this before request_service' guidance. Usage is only implied by the framing of a priced catalog that also states limits and what is not offered, which an agent can infer as a discovery/scoping step but must guess at.

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