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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so safety is covered. The description adds real context beyond them: the required scope (referrals:manage), an explicit risk classification, 'Efeitos: Nenhum', and crucially the authorization-dependent unavailability, which the agent cannot derive from annotations. It does not describe output shape or data freshness.

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?

Two short lines, with the substantive content (what the funnel covers) front-loaded before the operational metadata. The 'Risco: read · Efeitos: Nenhum' clause partially duplicates the readOnlyHint/destructiveHint annotations, which is mild waste, but the scope and availability notes earn their 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?

With no parameters, no output schema, and rich annotations, the description covers what is missing elsewhere: it describes what the result contains (funnel stages, earnings, owner agreements) in lieu of an output schema, plus auth scope and availability. An agent has everything needed to decide whether it can and should call this tool.

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 no parameter semantics to explain and the baseline of 4 applies. The description correctly implies a fixed, context-scoped result set ('do usuário conectado') rather than a filterable one, which prevents the agent from expecting arguments.

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 names a specific resource and enumerates its contents: referral funnel stages (cadastro, teste, assinante, encerrado), earnings per referral, and property-owner agreements. That distinguishes it from siblings like list_referral_programs and create_referral_link, which manage programs/links rather than performance. It stops short of an explicit verb such as 'returns' or 'reports', so it is clear but not maximally sharp.

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?

There is no guidance on when to choose this over alternatives such as list_referral_programs or get_performance_report. The one strong usage signal is the availability warning ('INDISPONÍVEL nesta autorização'), which effectively tells the agent not to call it — valuable, but a when-not rather than a when-to-use with alternatives.

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