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

Annotations already declare this is a safe, read-only, non-destructive operation with openWorldHint false. The description adds that results are grouped per server within an OpenAPI spec, but it does not clarify how the target spec is identified or what the response shape looks like.

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?

The description is a single focused sentence with the resource and scope front-loaded. It is efficient, though the phrase 'specific OpenAPI spec' is slightly ambiguous given that no input parameter identifies the spec.

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 zero-parameter read-only tool with annotations covering safety, the description is minimally adequate. However, it leaves an important ambiguity about how the 'specific OpenAPI spec' is determined and does not describe the return structure, which matters since no output schema exists.

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 has zero parameters, so there is no parameter semantics burden on the description. The baseline for zero parameters is 4, and the description does not need to compensate for schema coverage gaps.

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 uses a specific verb and resource: it gets server variables for each server within an OpenAPI spec. This is clear enough for an agent to understand the tool's basic purpose, though it does not distinguish itself from siblings such as get-endpoint or fetch.

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 description provides no explicit guidance on when to use this tool versus alternatives like fetch, get-endpoint, or search-endpoints. Usage is only implied by the scope of returning server variables for an OpenAPI spec.

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