validate_boleto

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

With no annotations provided, the description discloses the validation algorithm (mod 10 for fields, mod 11 for DV) and the return structure ({ valid } and { reason } on invalid). It doesn't mention side effects, but this is a read-only validation tool, and the behavior is clearly described.

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 two concise sentences: the first states the main purpose and input format, the second details the validation logic and return. Every sentence adds value 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?

Despite having no output schema, the description clearly explains the return format ({ valid } and { reason } when invalid) and the validation approach. After reading, an agent knows exactly when to use it and what to expect, making it complete for its complexity.

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 100% for the single parameter, already specifying the 47-digit length and optional punctuation. The description adds no additional parameter semantics beyond what the schema provides, matching the baseline score.

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 validates the readable line of a bank boleto, specifying the 47-digit format and punctuation acceptance. It also details the validation logic (mod 10 and mod 11), distinguishing it from sibling CPF/CNPJ validators and parse_boleto.

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 specifies this tool is for validating a boleto line, with explicit checks and return behavior. While it doesn't name alternative tools, the context of siblings makes it clear this is for boleto validation, not CPF/CNPJ, and parse_boleto handles parsing rather than validation.

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