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

Annotation readOnlyHint=true already marks the operation as read-only; the description reinforces this with 'Read-only' and specifies the GET endpoint. It adds the returned fields (language, source URL, default flag), which is useful context. It does not go into edge cases like empty results, but for a non-destructive GET this is adequate.

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 entire description is one short sentence plus the endpoint and 'Read-only'. Every fragment earns its place and the key action is front-loaded.

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 list operation with three well-documented parameters and no output schema, the description tells the agent what is returned (language, source URL, default flag), the endpoint, and the read-only nature. Missing details like pagination behavior are already in the schema. No critical information for selecting and invoking the tool is absent.

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%; videoId, pageSize, and currentPage each have descriptions. The tool description adds only the semantic context of what a caption track contains, which is helpful but does not change the parameter meaning.

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 for a video', naming a specific verb, resource, and scope, and adds the fields returned in parentheses. This distinguishes it cleanly from sibling list tools such as list_chapters or list_videos.

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 implies the tool is for retrieving caption tracks for a given video, but it does not explicitly state when to prefer it over alternatives or when not to use it. No exclusions or references to sibling tools are provided.

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