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

Annotations already mark the tool as read-only and open-world, and the description adds meaningful behavioral disclosure: results may be empty, 'total' reflects only this list, and there is no page 2. It also instructs the agent to show adoption_url and not fabricate pets, which is valuable runtime guidance beyond the structured 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 compact and front-loaded with the core purpose, then adds only high-value operational details: when to use, fallback behavior, output requirements, and pagination absence. Every sentence earns its place with no redundancy or 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 two-parameter read-only tool with a full input schema and an output schema, the description covers all essential calling context: search scope, trigger condition, empty-result handling, required display field, and pagination behavior. Nothing necessary for correct invocation is missing.

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 description coverage is 100%, so the schema already fully documents pet_ref and limit, including the max of 24 and absence of pagination. The description adds context about search criteria (same species and city) and output behavior, but not new parameter-level meaning, so the baseline of 3 is appropriate.

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 names a specific action and resource: finding pets similar to one specific pet, restricted to the same species and city. It explicitly distinguishes itself from the general catalog search ('não é a busca geral do catálogo') and from the sibling tool search_pets, so an agent can select it correctly.

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 gives a clear trigger condition: 'Use quando o pet desejado já não estiver disponível.' It also names the alternative (searchPets) and explains what to do when the result is empty: use searchPets and never invent pets. This is explicit when-to-use guidance with a fallback path.

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