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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds the payload contents (persons, addresses, tax/registration numbers, default accounts, credit limit), which is genuinely useful, but says nothing about behavior for a missing or invalid id, or whether the response is a nested object.

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 short sentences, front-loaded with the payload contents and ending with the endpoint mapping. Every clause carries information; only the field enumeration borders on verbose, and it earns its place since there is no output schema.

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 one fully documented parameter, rich annotations and no output schema, the description usefully summarizes the returned record shape and the underlying endpoint. The only gap an agent might need is error/missing-contact behavior, which is minor for a simple read.

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% for the single contact_id parameter and it is already documented as 'Bukku contact id.' with positivity/range constraints. The description adds no format or sourcing hints (e.g. obtained from bukku_list_contacts) beyond the {id} path template, 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?

States a specific verb (implicitly fetch, via the GET endpoint) and resource (a single contact) and enumerates what the record contains, which distinguishes it from the list sibling. It never says outright 'retrieve' but 'One contact with ...' plus the GET path makes the purpose unambiguous.

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?

The phrase 'One contact' contrasted with bukku_list_contacts is an implicit usage signal, and the endpoint pins it to an id-based fetch. There is no explicit when-to-use/when-not or any mention of the list alternative by name, so guidance remains implied.

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