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

Annotations already declare readOnly and idempotent, and the description adds useful context: it does not consume a quota and the limit is shared across client systems. This goes beyond what annotations alone provide.

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?

Three short sentences, each earning its place: the result is front-loaded, the crucial non-consuming note follows, and usage guidance ends. No wasted words.

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 one-parameter read-only tool with no output schema, the description covers the return concept (remaining queries and blocked status), the non-consuming behavior, and the best time to call it. It is complete enough for an agent to use it correctly.

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 description references a CNPJ and the schema has a single 'account' string parameter, so the mapping is inferable. However, with 0% schema description coverage, the description should more explicitly state that 'account' is the CNPJ. It adds some meaning but does not fully compensate for the missing schema guidance.

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 reports remaining quota and block status for a CNPJ. It is specific and distinguishes itself from siblings by explicitly noting it does not consume a query, unlike tools like dfe_consultar_chave.

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 an explicit recommendation: 'Chame isto antes de uma carga grande'. It also explains the context behind the recommendation, the SEFAZ per-CNPJ limit. It does not discuss exclusions or alternatives, but the intended usage is clear.

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