List transcript tracks

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds genuinely useful operational context beyond annotations: the video may be passed as an ID or URL and no API key or quota is consumed. It doesn't describe return format, but that is secondary for a simple read-only listing operation.

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?

Two short sentences, with the action front-loaded and no filler. The auth/quota note is a meaningful extra detail rather than repetition of the schema or annotations.

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?

With one simple parameter, rich safety annotations, and no output schema, the description supplies the essential invocation details: what the tool lists and how to specify the video. It could mention the shape of the returned track list, but an agent can still call the tool correctly without that.

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 0%, so the description must compensate. The parenthetical 'ID or URL' defines what the 'video' parameter means, which is the main semantic an agent needs beyond the property name. For a single-parameter tool, this is adequate.

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 'List caption tracks available for a video', which clearly names the verb and resource. The word 'available' distinguishes it from get_transcript, which would fetch the transcript content, so an agent can tell them apart.

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 implies a natural workflow of listing tracks before fetching a transcript, but it never names the sibling tool get_transcript or states when not to use this tool. The 'ID or URL' and 'No API key or quota needed' details give practical context but do not explicitly compare alternatives.

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