get_transcript_languages

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

With no annotations, the description carries the behavioral burden, and it does disclose the return content categories (language codes and names, manual and auto-generated captions), which is meaningful context. It does not discuss permissions, rate limits, or error behavior, but for a simple read-only enumeration that is a minor gap.

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?

Three sentences, each earning its place: purpose, return contents, and workflow ordering. The core purpose is front-loaded and there is no filler.

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?

An output schema exists, so the description need not enumerate return fields, and it still adds the useful manual-vs-auto distinction. Combined with the workflow guidance and full parameter documentation, an agent has everything needed to call it 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 100%, and the single 'video' parameter is fully documented in the schema as a URL or video ID. The description adds no format, alias, or validation detail beyond that, so the baseline 3 applies.

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?

States a specific verb (List) and resource (available caption/transcript languages) with the scope of a YouTube video, and explicitly notes it covers both manual and auto-generated captions. This clearly separates it from the sibling get_video_transcript, which fetches content rather than enumerating languages.

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 final sentence gives explicit sequencing guidance: call this first to discover available languages before fetching a transcript, which directly references and routes relative to the sibling get_video_transcript. An agent knows both when to use it and what to do next.

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