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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is fully covered. The description adds two pieces of real behavioral context – results are filtered to languages with a playable channel, and each entry includes a count – but says nothing about ordering, pagination, or result shape.

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?

A single short clause with no filler, and the scope qualifier is front-loaded. It is slightly hurt by being a noun phrase rather than a full statement, and by being written in Portuguese while the tool ecosystem and sibling names are English.

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?

This is a parameterless read-only lookup with no output schema, so the description only needs to convey what comes back: a filtered set of languages with per-language counts, which it does. It stops short of describing result ordering or structure, which an agent assembling a response would need.

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 the baseline is 4. The schema is empty with 100% coverage and there is nothing for the description to compensate for on this dimension.

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?

It names the resource (languages) and constrains the scope to those that have a playable channel, plus notes each entry carries a count. That is more specific than a bare 'list languages', but it never distinguishes itself from the many sibling list_* tools (list_cities, list_countries, list_networks, list_qualities) or states the list verb explicitly.

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 qualifier 'que têm canal tocável' implicitly tells the agent this returns only languages with playable content, which is a usage-shaped scope. However there is no explicit when-to-use, no when-not-to-use, and no pointer to an alternative sibling tool.

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