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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds value beyond them by disclosing that no API key is required — a real behavioral fact an agent needs before credentials exist.

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?

One short sentence plus a two-word qualifier, front-loaded with the main outcome. Nothing is wasted, though the 'Sem chave' fragment reads slightly abrupt.

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 no-parameter read-only health check with rich annotations and no output schema, the description covers what the agent needs: what is checked and that no authentication is required. A brief hint at the shape of the returned status would make it complete.

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 takes zero parameters, so there is nothing for the description to disambiguate; the baseline applies. No parameter information is missing.

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 states a specific check: whether 'emissaoja' is online and the health of the fiscal engine. It distinguishes itself from credential-related siblings like 'situacao_credencial' by naming the two subsystems it reports on, though it never explicitly contrasts with them.

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?

Usage is only implied. The tag 'Sem chave' hints that this can be called before configuring credentials, which is a useful signal, but there is no explicit statement of when to prefer this over 'situacao_credencial' or 'acompanhar_operacao'.

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