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

The annotations are all false/default (readOnlyHint false, idempotentHint false, destructiveHint false), providing no effective safety or behavior profile, so the description carries the burden. It does not disclose what happens on creation — no mention of idempotency despite an idempotency_key parameter, no duplicate/error behavior, no response description. The 'never invent UUID' rule guides agent input but does not reveal tool behavior.

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, each earning its place: purpose first, then the critical value rule with the prerequisite sibling tools, then a concrete example. No fluff, no repetition of schema content, and the most important constraint (names not IDs) is front-loaded.

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 is sufficient for a basic invocation of the five required parameters — account and is_income are clarified, and description/amount/date are self-evident. But with no output schema, empty annotations, and 13 parameters, it leaves meaningful gaps: idempotency_key semantics, recurring/periodicity behavior, the done flag, and the distinction from mass_create_transactions all go unaddressed. Adequate for selection, incomplete for advanced correct invocation.

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?

With schema description coverage at 0%, the description compensates partially: the example (account: 'Nubank', category: 'Alimentaçao', is_income: false) gives real value semantics for three parameters — human-readable names, not IDs — which the bare string schema completely lacks. However, 9 of 13 parameters (date format, done, tags, times, recurring, observation, periodicity, idempotency_key) receive no explanation, so the compensation is incomplete.

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 states a specific verb and resource — 'Cria uma transaao (receita ou despesa)' — and the parenthetical clarifies the two accepted transaction types. Among the many create_* siblings (account, budget, category, credit_card, transfer), the resource word 'transaao' makes the target unambiguous. It lacks an explicit contrast with sibling create tools, but the verb+resource pairing is specific enough to select it correctly.

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 gives actionable when-to-use guidance: 'Prefira NOMES de conta/cartão e categoria (list_accounts / list_credit_cards / list_categories primeiro se não souber)' names the exact sibling tools to call first and the condition that triggers them. 'Nunca invente UUID/id' sets a hard behavioral rule. It does not, however, contrast with alternatives like mass_create_transactions or update_transaction, so exclusion guidance is partial.

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