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

No annotations exist, so the description bears the full burden. 'Fetch' and 'customer-visible' do disclose the operation is a read and that results are scoped to customer-visible services, which is real behavioral context. It does not say what happens when a key is missing/invalid or whether auth/tenant scope applies.

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 sentence with the resource and the key parameter front-loaded, and the return-field list in parentheses. No filler.

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 simple one-parameter read, the description covers purpose and return shape, which substitutes for the absent output schema. It still leaves gaps on key provenance/format, error behavior, and its relationship to list_services.

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 0%, so the single service_key parameter has no structured documentation. The description only restates that the key identifies the service; it gives no format or source hint (where the key comes from). It does compensate somewhat by listing the response fields, which is useful since there is no output schema.

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 ('Fetch') and resource ('one customer-visible catalog service') keyed by service_key, and enumerates the fields it returns. The singular 'one' distinguishes it from list_services without naming that sibling explicitly.

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 requirement to supply a service_key implies this is the lookup path once a key is known, and 'one' implies complementarity with a listing tool. However, it never names list_services as the way to discover keys, nor states when not to use it (e.g., bulk retrieval).

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