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

Annotations already indicate read-only and non-destructive behavior. The description adds extra context: the tool is free, and it explains how the returned id feeds into tegas_start_video, including the default behavior. This 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 zero waste. It front-loads the cost ('Free.') and immediately gives the core purpose, followed by the critical integration detail. Every word earns its 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?

For a single-parameter, read-only listing tool with an output schema, the description covers everything needed: what it returns, how to use it, and when to skip it. The output schema presumably documents the item structure, so the description need not repeat that. It is complete for an agent to call 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?

With 0% schema description coverage, the description carries the burden of explaining the parameter. It lists the accepted languages, which aligns with the enum, and implies the language parameter is used for filtering. It doesn't mention the default value, but the schema provides that. The description adds meaningful semantics beyond the bare schema.

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 ('List') and resource ('voice-over voices') with the supported languages. It clearly distinguishes itself from siblings by explaining the relationship to tegas_start_video, making its purpose 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?

It explicitly explains when to use this tool (to obtain a specific voice id) and when it is unnecessary (when the default voice suffices), going so far as to call it 'optional.' This provides clear guidance on selection and use.

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