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

The description goes beyond the destructiveHint annotation by explicitly stating the operation is irreversible and that declared numbers can never be used again. It also warns about the risk of burning numbers if the range is wrong, and mentions SDK-level validations before transmission, giving a full picture of the tool's side effects.

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 somewhat lengthy but every sentence adds critical information about usage, constraints, and side effects. The structure is clear, with repeated emphasis on key points (irreversibility, application scope, and confirmation) that are essential for safe invocation.

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?

Given the operation's destructive and irreversible nature, the description covers all necessary context: when to use it, when not to use it, what validation the SDK performs, and the need for user confirmation. The existence of an output schema is not relevant to explaining the tool's behavior, and no critical context appears missing.

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?

While the schema lists parameters without descriptions, the tool description provides meaningful context: it explains the reason must be 15-255 characters and that the range must be non-backwards. It does not define 'series' explicitly, but the overall purpose and constraints give sufficient guidance for an agent to infer the parameters' roles.

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's purpose: declaring an NF-e numbering range as reserved but unused, to maintain continuous numbering. It explicitly contrasts this with issuing a new document and with canceling an authorized document, making it distinct from sibling tools like 'cancel_invoice' and 'issue_invoice'.

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 provides explicit usage guidance, including that it applies only to never-authorized numbers, that authorized documents should be canceled instead, and that the user must confirm the range before calling. It also indicates the SDK will refuse backwards ranges and invalid reason lengths, which helps the agent avoid invalid calls.

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