swagger-petstore---openapi-3.0.getUserByName

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

Annotations already provide readOnlyHint=true, idempotentHint=true, and destructiveHint=false, establishing the safety profile. The description adds no further behavioral detail such as not-found handling or auth requirements, but it does not contradict the annotations.

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, front-loaded sentence with no fluff. It is concise, though slightly too terse to compensate for the missing parameter details.

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 read-only getter, the purpose is clear and the annotations plus output schema cover safety and return shape. The main gap is the lack of any mention of the required username parameter, which makes the tool difficult to invoke correctly.

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 input schema defines zero parameters, so the description must carry the input meaning; 'by user name' does identify the logical lookup key. However, it does not specify a parameter name, type, or requiredness, leaving invocation details ambiguous for an empty 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?

The description 'Get user by user name' clearly states the operation: a single-user lookup by username, distinguishing it from create/update/delete user tools. It does not explicitly differentiate from the identically named 'petstore-api.getUserByName' sibling, so it misses full sibling differentiation.

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 guidance on when to use this tool versus alternatives such as loginUser or the duplicate getUserByName in petstore-api. No exclusions, prerequisites, or alternative tool references are provided.

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