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

Annotations only declare readOnlyHint and openWorldHint, but the description goes further: it discloses the 404 conditions (video not completed in the collection, or transcript predates the cache), auth/token behavior, cost default behavior, and the effective endpoint. This is rich, non-redundant behavioral context.

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?

Dense but each sentence carries distinct information (cost, endpoint, auth, format, error, pricing). The leading 'Free.' is punchy and front-loads the key differentiator, though the later pricing sentence is slightly at odds with it.

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 3-param read tool with no output schema, the description covers auth, format semantics, and failure modes. It could say a bit more about the returned payload structure, but nothing needed to invoke it correctly is missing.

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 baseline is 3, but the description adds real meaning: collection_id's requirement flips depending on API key vs `ct_` token, and format is spelled out (json = timestamped segments, text = one `[H:MM:SS] text` line per segment) beyond the schema's terse enum note.

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+resource (get the transcript of a video) and scopes it ('completed in one of your collections'). The endpoint mapping (GET /v1/videos/{youtubeId}/transcript) and the free/non-free framing against the sibling 'transcribe' make it distinguishable from siblings without opening schemas.

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?

Gives explicit conditions: collection_id required with an API key but defaulted with a `ct_` token, and format selection. It also routes pricing questions to the sibling 'quote'. However it never directly contrasts with 'transcribe' (the tool that presumably produces the transcript), leaving that inference to the reader.

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