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

Annotations provide readOnlyHint=true and openWorldHint=true, and the description goes well beyond these by disclosing asynchronous behavior (returns 'processing'), caching (24h per url), pricing (pack minutes), and limits (15 min without key, daily IP limit). No contradiction with annotations; it adds substantial 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?

The description is three sentences, each adding value: purpose, async retry, caching, and pricing/limits. It front-loads the core function and avoids fluff. Slightly dense but efficient and well-structured.

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?

Given the tool's complexity (async, pricing, limits, multiple formats) and lack of an output schema, the description covers the key behaviors and mentions the transcript with timestamps. It does not describe the full response structure, but the format parameter covers output variants. It is adequate for an agent to call correctly.

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 100%, so all parameters are already well documented in the schema. The description adds behavioral context (e.g., 'just call again' relates to wait_seconds) but does not add meaning beyond what the schema provides. Baseline 3 is appropriate when schema does the heavy lifting.

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 verb ('Download') and resource ('public video') and explicitly names the output ('full transcript with timestamps'). It distinguishes itself from siblings (get_chapters, suggest_clips) by being about the full transcript, so an agent can tell it apart without opening other tools.

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 gives clear context about when to call again (async processing) and mentions limits (15 min without key), but it does not explicitly state when to use this tool versus get_chapters or suggest_clips, nor does it provide exclusions. Usage is implied by the purpose but not contrasted with alternatives.

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