Saldo do Flow

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description still adds real context beyond them by promising the call consumes no credits, which matters in a family where most flow_* tools do spend credits.

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?

One short sentence, front-loaded with the action and resource, with the no-cost caveat tucked into a parenthetical. Nothing superfluous and nothing buried.

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 zero-parameter read tool this covers what an agent needs: what it returns conceptually (credit balance) and that it is free to call. It does not say whether the balance is broken down per model or account-wide, but no output schema or params create obligations here.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The schema is empty and fully consistent with the described read-only balance check.

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: shows the Google Flow credit balance for the account. It implicitly separates itself from the spend-tracking siblings (flow_gastos, flow_custo) by being a balance read, though it never names them explicitly.

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 parenthetical '(não gasta nada)' implies it is safe to call at any time, and the credit framing suggests it belongs before credit-consuming operations like flow_gerar_video. However, no explicit when-to-use guidance or routing to flow_gastos / flow_custo / flow_status is given.

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