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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so safety is covered. The description adds meaningful behavior beyond annotations: it specifies that only unpaid transactions and credit card invoices due in the window are returned, and states the default period of 7 days.

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 compact, front-loaded with the core purpose, and includes both a natural language question and the default behavior. Every piece of text adds value without wasted wording.

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 simple read-only listing tool, the description conveys the main behavior and default window, and the annotations cover safety. However, the start_date parameter is not explained and there is no output schema, so the description is not fully self-sufficient for 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?

Schema description coverage is 0%, so the description must compensate for parameter meaning. It only clarifies the default of '7 dias' for the days window, but says nothing about start_date, its format, or how it interacts with the days parameter. This leaves a material parameter undocumented.

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 identifies the tool's purpose: returning upcoming bills, specifically unpaid entries and credit card invoices due within a window. The embedded question 'o que vence essa semana?' makes the use case immediately understandable and helps distinguish it from broader sibling tools like list_transactions or get_credit_card_invoices.

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 clear usage context by defining the tool as answering 'what is due this week?' and notes the default 7-day window. It does not name alternatives or state when not to use it, but it is sufficient for an agent to infer typical use.

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