Get download links

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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds genuine behavioral context not present in structured data: the required scope being off by default, and that links are signed and expire within hours. That expiry detail is exactly the kind of trait an agent must know to avoid handing out stale URLs.

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?

Three sentences with zero filler: purpose first, then the scope requirement, then the exclusivity claim. Every sentence carries distinct, decision-relevant information and nothing is repeated from the schema or annotations.

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 read-only, single-parameter tool with no output schema, the description covers purpose, auth prerequisite, result lifetime, and uniqueness. An agent has everything needed to decide to call it and to interpret its output safely.

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% for the single video_id parameter, so the schema already carries the parameter documentation. The description adds no format or syntax detail beyond referring to 'a video's source and rendered files', so the baseline 3 applies.

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 direct download URLs for a video's source and rendered files') and clarifies the scope of what is returned. No sibling tool offers downloads, so differentiation is inherent and the description makes the unique purpose 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?

Gives a prerequisite ('Needs the video_files scope, which is off by default on a new token') and a routing statement ('the only way to retrieve an original file through the API'). It does not name an alternative sibling to use for other retrieval needs, but the prerequisite context is unusually actionable.

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