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

With no annotations, the description must carry the burden of behavioral disclosure. It only says 'Update', implying mutation, but does not clarify whether it is a partial or full update, authentication requirements, or error behavior such as what happens if the pet does not exist. It also does not specify how 'by Id' is encoded (path vs body).

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 redundant: 'Update an existing pet. - Update an existing pet by Id.' The second sentence adds minimal information. It is under-specified rather than concise, and the structure is poorly organized.

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?

The tool has nested object parameters, no output schema, and no annotations. The description provides no information about return values, error handling, or preconditions. This is insufficient for an AI agent to invoke the tool correctly, especially since the schema has low coverage.

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 description adds no meaning to the parameters. The schema has 0% description coverage, and the description does not explain updatePetBody or x-hapi-auth-state. It merely repeats the tool's purpose without detailing parameter usage or types.

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 clearly states the verb 'Update' and resource 'existing pet', and mentions 'by Id' which identifies the target. However, it does not differentiate from the sibling tool updatePetWithForm, which also updates pets, so it lacks 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 updatePetWithForm or other update tools. No context, exclusions, or alternatives are mentioned, leaving the agent without decision support.

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