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

Annotations only flag readOnly=false, openWorld=true, destructive=false. The description adds substantial behavior beyond that: a 30-minute URL expiry, the signed Content-Type requirement, size (100 MB) and duration caps (60 s demo / 15 s hook), and the semantics of the returned key — exactly the mutation details annotations cannot convey.

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 dense sentences, front-loaded with the core action and constraints, then the call mechanics, then the return-value usage. No filler; every clause carries a constraint or instruction.

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?

With only one parameter, no output schema, and a single creation action, the description covers everything an agent needs: format/size/duration limits, the exact PUT procedure, the signed header requirement, and what the returned key is used for.

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 0%, so the description must carry the parameter's meaning, and it does: it spells out the accepted formats (mp4/mov/webm) matching the contentType enum and requires the same Content-Type header on the PUT. It does not restate the enum values verbatim, but the mapping is unambiguous.

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 (Create) and a precisely scoped resource (a 30-minute presigned PUT URL for a Video Hook & Demo recording), including the exact downstream use (a Video Hook & Demo content job). This is clearly differentiated from sibling upload-URL tools like create_clip_upload_url and create_studio_upload_url.

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 operational context: PUT the bytes to uploadUrl with the signed Content-Type, and the returned key feeds demoVideoKey/hookVideoKey. It does not explicitly compare against the clip/studio upload-URL siblings or state when each is preferred, so it stops short of full when/when-not guidance.

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