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

Annotations already declare readOnly=false, idempotent=false, destructive=false. The description adds meaningful mutation context: a hard limit of 12 sub-tabs per folder and a response that includes the fully updated library, removing the need for a follow-up GET /api/library. It does not describe what happens when the limit is exceeded, so it is not fully complete.

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 sentences, front-loaded with the core action. The limit and response behavior are stated efficiently with no filler, and the follow-up API call guidance is directly actionable.

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 two-parameter mutation with no output schema and full schema coverage, the description supplies the key operational facts: what it creates, the per-folder limit, and that the response already includes the updated library. Error handling for exceeding the limit is not covered, but the core calling context is complete.

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 both parameters (category_id and name) are already documented with types and constraints. The description adds no further parameter syntax or format details beyond the schema, making the baseline 3 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?

States a specific verb and resource: creates a sub-tab inside a category. This distinguishes it from create_category, which likely creates the parent folder. However, the tool name 'create_group' and the description's term 'sub-aba' are not identical, so the naming alignment is slightly loose.

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 guidance on when to use this tool versus siblings like create_category, nor any exclusions. The intended scenario is implied by 'Cria sub-aba numa categoria,' but an agent must infer the boundary between creating a category and creating a sub-tab.

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