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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds useful semantics about the 'principal' flag and its interaction with emitir_nota. It does not disclose that results are filtered by the ativos parameter by default (default '1'), which is a real behavioral trait an agent should know.

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 sentences with no filler; the resource and returned fields come first, and the cross-tool dependency note follows. Every clause carries information an agent can use.

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 read-only single-parameter list tool with annotations and no output schema, the description covers what is returned and why it matters to emitir_nota. It leaves the active/inactive filtering behavior and ordering/results size undocumented, which an agent needs to interpret the response 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?

Schema description coverage is 0%, so the description must compensate for the sole parameter, and it does not mention 'ativos' at all. The enum values '1'/'0'/'todos' with default '1' are guessable but unexplained in either location. The description spends its words on returned fields rather than on controlling the filter.

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 the resource (registered company services) and enumerates the key returned fields (descrição, código nacional de tributação, ISS, principal), which makes it distinguishable from siblings like listar_tomadores and listar_notas. It lacks an explicit verb ('listar'), but the intent of retrieving catalogued services is unambiguous.

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 second sentence hints at the main downstream use case: emitir_nota falls back to the 'principal' service when servico_id is omitted, implying this tool is where an agent looks up service IDs. It never states explicit when-to-use/when-not-to-use rules or any alternative for looking up services. Usage is implied rather than prescribed.

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