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

Annotations indicate a write operation (readOnlyHint=false), and the description says 'Cria' (creates), so there is no contradiction. The description adds useful context about the required fields and recurring/installment behavior beyond the annotations. However, it does not disclose side effects like authentication prerequisites or potential validation errors, which is a minor gap given annotation coverage.

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 sentences: the first states the core action and required fields, the second explains how to achieve specific behaviors (installments vs recurrence). It is front-loaded, concise, and every sentence adds value without fluff.

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?

Given the tool has 9 parameters, no output schema, and moderate complexity, the description covers the required fields and the two most nuanced parameter groups (installments and recurrence). It omits the distinction from the plural sibling (poupa_add_transactions) and any prerequisites like authentication, but for a straightforward creation tool the basic usage is well covered. More context about single vs bulk or error handling would raise completeness, but it is adequate.

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 0%, so the description carries the burden. It explains the purpose of 'installments' (parcelar), 'expense_recurrency' (dias), and 'recurrency_array_dates' (lista de datas), which adds meaning beyond the schema. However, it only covers three of the nine parameters and does not explain 'category', 'card_name', 'description', or 'payment_bank', leaving ambiguity for those fields.

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 it creates a transaction with a specific verb ('Cria uma transação'). It distinguishes from the sibling 'poupa_add_transactions' (plural) by implying a single transaction, though not explicitly. The purpose is immediately clear.

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 usage guidance for recurring and installment transactions, explaining when to use installments vs expense_recurrency/recurrency_array_dates. However, it does not mention when to use this tool over the sibling 'poupa_add_transactions' (bulk add) or other alternatives, missing a clear exclusion statement.

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