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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds useful behavioral context by emphasizing the real-time nature ('AGORA') and detailing what the tool returns, which goes beyond the annotations without contradicting them.

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 two sentences with no wasted words. The core action and payload are front-loaded, and the usage guidance is appended compactly. Every clause earns its place, making it efficient for an agent to parse.

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 zero-parameter, read-only tool, the description covers all an agent needs: what it returns, when to use it, and how it differs from siblings. Annotations cover safety. The lack of an output schema is not a gap here because the description enumerates the return content explicitly.

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 has zero parameters and the input schema is empty, so the baseline is 4. The description does not need to explain parameters; it appropriately focuses on the output and usage. No parameter information is missing.

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 states a specific verb ('Retorna') and resource ('o que está tocando AGORA na Rádio Escola de Rádio'), listing the exact data returned (current/next song, listeners, stream link, how to listen). It also includes a usage line that differentiates it from sibling tools like school_info or search, so an agent can identify the tool instantly.

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 explicitly says when to use it ('Use quando perguntarem sobre a rádio da escola, o que está no ar, ou como escutar'), giving clear triggering contexts. It does not mention when not to use it or name alternatives, but given no sibling tool covers radio playback, the context is sufficiently clear.

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