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

No annotations are provided, so the description carries the full burden. It discloses a quota limit and the error code 402, which is a meaningful behavioral trait. However, it does not explain success response, idempotency, or whether an existing watch gets replaced. For a simple add operation, the quota disclosure is valuable but incomplete.

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 two concise sentences with no waste. The primary action is front-loaded, and the quota note is appended efficiently. It is well-structured and easy to parse.

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 description covers the core action and a key quota behavior, but it omits details about the success response and does not mention any prerequisites or side effects beyond quota. Given the tool's simplicity, the missing return information is a minor gap, but it is not fully complete for an agent to predict the outcome.

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 50% (only cnpj has a description). The description adds no parameter semantics beyond what the schema already provides; it does not explain session_id or elaborate on formatting requirements. It fails to compensate for the undocumented 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?

The description clearly states the verb 'Adiciona' (adds) and the resource 'CNPJ aos watches da sessão' (CNPJ to the session's watches). It distinguishes from siblings like list_watches (list) and get_cnpj (get) by specifying the action of adding to the session. The scope is explicit and unambiguous.

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 provides a quota constraint ('first 10 free, then 402') that implicitly guides usage, but it does not explicitly state when to use this tool over alternatives or mention exclusions. It lacks a contrast with sibling tools or conditions for when not to use it, so the guidance is only partially present.

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