Get Merchant Balance

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

Annotations already cover safety (readOnlyHint, idempotentHint, non-destructive). The description adds value by noting the balance is 'atual' (current) and gives trigger phrases, but doesn't describe edge cases like auth requirements or rate limits. This is acceptable given the strong 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 a single sentence with appended examples, front-loaded with the core action and result. Every word earns its place with no redundancy.

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, zero-parameter, read-only balance tool with strong annotations, the description covers what it returns (balance) and when to use it. It could specify currency or formatting, but the basic context is sufficient.

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 has zero parameters, so the description has no parameters to explain. The schema is empty and the description adds no parameter info, but the 0-parameter baseline is 4, and there is nothing needed beyond that.

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 uses a specific verb ('Consulta e retorna') with a clear resource ('saldo atual'), and provides example user queries. This unambiguously identifies the tool's purpose and differentiates it from siblings that handle transactions, customers, products, etc.

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?

Explicitly states when to invoke the tool: 'Chame imediatamente quando o usuario perguntar...' with concrete query examples. Though alternatives are not mentioned, no sibling tool serves a similar purpose, so the guidance is complete.

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