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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely new behavioral context: manual transcripts are preferred over auto-generated ones, and offset/max_chars enable paging through long output. It does not mention rate limits or failure modes for videos lacking captions.

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?

One-sentence purpose statement up front, then a dense parameter list where every line adds information the schema lacks. No filler, boilerplate, or restatement of the tool name.

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?

Since an output schema exists, return-value explanation is not required, and the input side is thoroughly documented including defaults and formats. The remaining gap is the absent guidance on how this relates to list_transcripts and what to do when a transcript is unavailable.

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 carries the full burden and does so for all five parameters: accepted video URL/ID forms, language priority order with preference for manual transcripts, the exact '[m:ss]' timestamp prefix format, offset as a character offset for paging, and max_chars as a per-call cap. This is meaningfully richer than the bare schema.

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?

States a specific verb and resource ('Get the transcript of a YouTube video as text') and even names the accepted URL/ID forms, so the agent knows exactly what comes back. It never mentions the sibling tool list_transcripts, so it misses the differentiation that would make it a 5.

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?

Usage context is only implied: 'offset' is described as paging through long transcripts, which suggests when to re-call, but there is no explicit statement of when to use this versus list_transcripts. No exclusions or prerequisites (e.g. videos with transcripts disabled) are given.

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

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds nothing behavioral beyond that — no note on network/rate-limit behavior or what happens when a video has no transcripts. With the lower bar set by annotations, this still adds little.

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 core purpose is front-loaded in a single sentence, followed by a terse Args block. Slight overhead from the Args header but no wasted prose.

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 one-parameter read-only list tool with an output schema present and annotations covering safety, the description is nearly sufficient. It tells the agent what is returned at a high level and how to supply the identifier; only return-value detail is deferred, which the output schema covers.

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 carries the burden and does compensate: it specifies the single 'video' arg accepts either a full YouTube URL or an 11-character video ID, which the schema does not state.

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?

States a specific verb and resource: 'List the transcript languages available for a YouTube video.' The 'list languages' framing is cleanly separated from the sibling get_transcript, though the description never names that sibling to reinforce the distinction.

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?

There is no explicit when/when-not guidance or mention of alternatives. The usage is only implied by the verb 'list' and the availability framing; an agent must infer that this is a discovery step before get_transcript.

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