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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered structurally. The description adds content context (pricing, who delivers the service) but says nothing about return shape, pagination, or auth — appropriate given the low bar set by the annotations, but not rich.

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 tight sentences, front-loaded with the enumeration of services so the agent can pattern-match a user question quickly, ending with the explicit alternative. No filler.

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 single-optional-enum, read-only list tool with full annotation coverage and no output schema, nothing an agent needs is missing: scope, trigger phrases, alternative route, and per-type meaning are all present.

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 coverage is 100% and the enum values are listed there, but the description goes beyond the schema by explaining what each value actually is (demo = gravação profissional com Ruy, R$ 350; mentoria = 1:1, R$ 250/h; b2b = treinamentos corporativos). That is genuine added meaning over bare enum tokens.

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?

States a specific verb (lista) plus resource (serviços da ER+) and immediately scopes it as being ALÉM dos cursos regulares, then names the sibling it is not (list_courses). An agent can distinguish it from list_courses without opening either 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?

Explicit trigger conditions are given ('Use quando aluno perguntar sobre demo, mentoria, treinamento empresarial') along with the routing rule for the alternative ('Pra cursos regulares, use list_courses'). Both when-to-use and when-not-to-use are covered.

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