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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds genuinely useful behavior beyond that: the result ordering ('mais comuns primeiro'), the caveat that most of the catalog is SRD, and the fact that returned slugs feed a `breed` filter elsewhere.

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?

Three short clauses, front-loaded with scope and ordering before the usage trigger and caveat. Nothing is redundant and every sentence carries information an agent needs.

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?

With an output schema present, return values need no explaining, and the description still covers scope, ordering, a data caveat and cross-tool linkage. The only gap is any hint about what the `species` filter does, which the schema happens to cover.

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 single `species` parameter is fully documented in the schema (100% coverage), so the baseline is 3. The description never mentions `species` at all; its `breed`/slug sentence concerns how the output plugs into other tools, not the input parameter.

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+resource ('Raças com pets no catálogo hoje') and adds scope that the title alone does not convey: only breeds that actually have pets listed, sorted by commonality. No sibling overlaps with this function, so an agent can distinguish it immediately from search_pets and the other search_* tools.

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?

Gives an explicit trigger ('Use quando perguntarem quais raças existem ou antes de filtrar por raça'), which routes the agent well. It stops short of naming alternatives or stating when NOT to use it, so it lacks the exclusion half of a 5.

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