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

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false). The description adds genuinely useful behavior the annotations do not carry: the 8-folder-per-owner ceiling and the fact that the response returns the entire refreshed library, so a follow-up GET /api/library is unnecessary. It still omits failure behavior when the cap is exceeded, which holds it back from a 5.

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, front-loaded sentences with zero filler: action first, constraint second, return-behavior third. Every sentence earns its place and no restatement of the name or schema.

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 one-parameter mutation tool with no output schema, the description covers purpose, the key limit, and the return payload (full updated library), which is exactly the missing-output-schema compensation an agent needs. Only the cap-exceeded failure path is left unspecified.

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% with a single documented parameter (name, up to 40 chars), so the schema already does the work. The description adds no syntax or format detail beyond it, making the baseline 3 correct.

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?

"Cria tab/categoria pessoal" states a specific verb and resource, and adds the scoping detail that it is a *personal* category. It is clear what the tool does, but it does not name or differentiate itself from any sibling (e.g. create_group), so an agent must infer the distinction from the name alone.

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 explicit when-to-use or when-not-to-use guidance, and no alternative tool is named. The 8-folder cap is a constraint, but it reads as a limit rather than a selection rule, leaving the agent to infer when this tool applies.

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