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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, covering safety and side-effect expectations. The description adds valuable behavioral context beyond annotations: it explicitly states 'No API key required' and specifies the return format (names and ISO codes). This enhances transparency without contradicting any annotation.

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 concise sentences: the first states the action and resource, the second covers return content and authentication. Every word earns its place, with no fluff or redundant restatement of the tool name or title. It is front-loaded with the primary purpose.

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 informational tool, the description is fully complete. It covers what the tool does, what it returns, and the authentication requirement. Since there is no output schema, explaining the return content is essential, and it does so clearly. No missing details for correct invocation.

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 there is nothing to explain beyond the schema. With schema description coverage at 100% (trivially), the baseline for zero parameters is 4. The description doesn't need to add parameter info and correctly focuses on return values and authentication.

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 begins with a specific verb ('List') and resource ('all languages supported by Scriptivox for audio/video transcription'), followed by the return content ('language names and ISO codes'). This clearly distinguishes it from sibling tools like transcribe_url or get_pricing, with no ambiguity about its function.

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 clearly states the tool's purpose, making it obvious when to use it (e.g., when needing to know supported languages for transcription). While it doesn't explicitly name alternatives or exclusions, the simplicity of the tool and its distinct resource make the usage context clear. No misleading guidance is present.

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