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

The annotations already declare readOnlyHint=true, and the description adds that the operation returns serialized text, which is useful. However, it does not disclose behaviors such as required project context, how video_id relates to project_id, or likely file naming/encoding details. With annotations covering the read-only safety profile, this is adequate but not rich.

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 a compact two-sentence definition with no filler. It front-loads the core action and output format, then adds the return value in a separate short sentence. Every word contributes.

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?

The tool has no output schemahare, 0% schema description coverage, and no usage/exclusion guidance. An agent still cannot confidently infer whether video_id is optional, why project_id alone is required, or what 'serialized text' precisely looks like. The description is too thin for the tool's parameter ambiguity.

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. It mentions SRT and VTT, which maps to the format enum, but it adds no meaningful explanation for the required project_id parameter or how video_id relates to it. The phrase 'a video's caption rows' weakly implies video_id, but the parameter roles remain underspecified.

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 names a specific verb ('Export'), resource ('a video's caption rows'), and concrete output ('a subtitle file (SRT or VTT)'). It also states the return behavior ('Returns the serialized text'), making the tool's purpose unmistakable and distinguishably different from sibling tools like video_editor_export and video_editor_upload_captions.

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 purpose clearly implies when to use the tool: whenever caption rows need to be exported as an SRT or VTT subtitle file. However, it gives no explicit guidance about when not to use it or how it compares to related siblings such as video_editor_export or video_editor_upload_captions.

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