Inspect video and caption availability

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds 'cheap' (performance expectation) and specifies the exact data returned, plus its diagnostic role. This adds context beyond annotations without contradiction, though it omits details like pagination or rate limits, which are not critical for a read-only info tool.

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 core purpose and output, then the usage context. No wasted words; every sentence 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 single-parameter read-only info tool with full schema coverage and annotations covering safety, the description is complete. It tells the agent what it returns, when to use it, and why, leaving nothing essential missing for correct invocation.

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% – the url parameter is thoroughly described in the schema, listing all supported URL formats. The description adds no additional parameter information, so the baseline 3 applies. It does not compensate for any schema gap because there is none.

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 ('Cheap report for one video') with concrete output fields (title, author, duration, caption languages), clearly distinguishing it from siblings like youtube_get_transcript and youtube_parse_url. The purpose is unambiguous and the tool's role in the transcript workflow is explicit.

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 provides clear context: 'Call it before a batch of transcript requests, or to explain why a transcript is missing.' This tells the agent when to use it, though it does not explicitly name the alternative tools or state when not to use it (e.g., 'if you need the transcript text, use youtube_get_transcript'). The guidance is sufficient but lacks explicit exclusions.

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