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

Adds significant behavioral details beyond annotations: date pairing, window constraint, client-side keyword filtering, multi-account parallel aggregation with errors array, and pagination prohibition. These are not captured by readOnlyHint/idempotentHint/destructiveHint.

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 concise for the amount of information conveyed, but a bulleted or structured format could improve readability. No unnecessary sentences.

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?

Covers all 7 parameters with usage rules, aggregation constraints, and filtering details. No output schema exists, but the description does not need to explain return values as per rules. Complete for accurate tool 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 0% schema description coverage, the description fully compensates by explaining each parameter's role, constraints (e.g., start_date/end_date paired, limit range 5-100, next_page_start_key prohibited when accounts>1), and optionality.

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 tool retrieves credit card statements ('Extrato de cartão de crédito'), with a specific verb (extrato) and resource. It distinguishes from sibling 'contasimples_statement_banking' which handles banking statements.

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?

Provides clear usage context: date pairing, window limit, optional types, limit range, and aggregation behavior. Does not explicitly state when not to use or list alternatives, but the constraints guide correct usage.

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