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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds beyond these: probing every 5 minutes, free/no-key access, safety of frequent calls, and the caveat that missing/unknown/stale observations are not proof of an outage. This materially helps an agent interpret results correctly.

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 front-loaded with the core state and component details, then moves to usage guidance. Every sentence adds value: status mapping, the stale-data caveat, and the two explicit call scenarios all justify their place without 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?

With no output schema, the description adequately describes what the tool returns: overall and per-component states with latencies and an operational/degraded/unavailable/unknown mapping. It also covers the practical decision context and refresh behavior, so an agent has what it needs to invoke and interpret the tool 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 input schema has zero parameters, so there is nothing to document; baseline is 4. The description adds invocation-relevant context by stating the API needs no key and is free to call often, which lets the agent call without setup concerns.

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 the real-time operational state of Lunium services, naming the components (api, pix_charge, crypto_sale, webhooks, contract_docs) and the status mapping. This distinguishes it from the payment-operation siblings, which all act on charges or sales rather than observe service health.

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 explicit when-to-use guidance: call it before debugging your own integration, and after failures with erro=provedor_indisponivel or tempo_esgotado. It also tells the agent what to do instead when a rail is degraded (wait or inform the user), which is strong behavioral routing.

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