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

Annotations already disclose the safety profile (readOnlyHint=false, destructiveHint=true, openWorldHint=true, idempotentHint=false), so the burden is partly lifted. The description adds that it submits an async Builder task with a fixed collector id, which is real workflow context, but it does not explain that the call returns a task ID rather than the transcript itself, nor what must be polled afterward.

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 first sentence is a long, repetitive keyword-trigger dump that consumes space without adding information. The actual useful content (the collector id) arrives second and is the only sentence that earns its place.

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 5-param open-world scraping tool with no output schema and strong annotations, the description should at least convey the async task lifecycle or that results are retrieved elsewhere. It correctly mentions the Builder task and fixed collector, but leaves the caller unsure how output is obtained.

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 coverage is 100%, so every parameter including video_id regex, defaults, and language/type values is already documented in the schema. The description only echoes the collector id and adds no format or semantic detail beyond the schema, warranting the baseline 3.

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 states a specific action (提交 YouTube 字幕文件采集 Builder 任务) and pins the collector identifier youtube_transcript_by-id, which distinguishes it from siblings like youtube_video or youtube_audio. It is clear what the tool does, though the opening trigger-phrase list is keyword-stuffed boilerplate rather than purpose specification.

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 lists trigger keywords (采集/抓取/爬取/获取/提取/下载) but never says when to choose this over youtube_video, youtube_audio, or scraper_task_result. No exclusions, no prerequisites, no alternative routing is given.

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