transcript_youtube_list_langs

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

With no annotations provided, the description carries the behavioral disclosure burden. It explicitly states 'Read-only', which is the key behavioral trait for a listing operation. It also reveals the output format (YAML) and that it mirrors a known command, providing additional context beyond the schema. Minor gaps remain about error handling or network behavior, but for this simple tool it's sufficient.

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, front-loaded with the action, and contains zero filler. Every phrase adds value: the resource, the fields returned, the output format, the read-only nature, and the CLI mirror. It is both concise and information-dense.

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 tool with no output schema, the description covers the essentials: what it lists, what is included, the format, and safety. The sibling context (other transcript tools) is not referenced, but the tool's scope is so clearly defined that this omission is minor. The description is fully adequate for an agent to decide when and how to invoke it.

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 input schema already fully describes the only parameter 'url' with the note 'YouTube video URL or bare 11-character video ID.' The description does not add new parameter-level details, so the baseline score of 3 applies because the schema provides complete coverage.

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 opens with a specific verb and resource: 'List the caption tracks available on a YouTube video'. It enumerates exactly what fields are returned (code, name, manual/auto/translated) and the output format (YAML). This unambiguously distinguishes it from sibling transcript tools like transcript_youtube_fetch and transcript_youtube_info.

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 makes the use case clear: to enumerate available caption tracks for a YouTube video. It doesn't explicitly name alternatives or state when not to use this tool, but the specific scope (listing vs fetching) gives enough contextual guidance. The mention of being read-only further sets expectations.

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