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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint, so the bar is lower. The description adds useful context about the recovery use case and single-item scope, but it does not disclose return format, error behavior, or prerequisites. It adds some value without fully describing behavior.

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 short sentences with no filler. The core action is front-loaded, followed by a precise usage boundary and sibling reference, making every word earn its place.

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?

The tool is simple, annotations cover safety and idempotency, and the description explains purpose and usage boundaries. However, there is no output schema and no mention of return value shape or the optional account parameter, so an agent still lacks complete context for all invocation scenarios.

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 carry parameter meaning. It clarifies that NSU identifies the specific document to fetch, which covers the required parameter, but the optional account parameter is never mentioned. This leaves a material gap for callers trying to understand all inputs.

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 opens with a specific verb 'Busca' and a scoped object: 'UM documento específico pelo NSU.' It also explicitly contrasts itself with dfe_sincronizar, so an agent can distinguish it from the main sibling without opening the schema.

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?

It explicitly states when to use the tool: to recover an item that failed decompression during synchronization. It also says it is not for sweeping the queue and names dfe_sincronizar as the alternative, giving clear when/when-not guidance.

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