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

The description's operative verb 'Mark ... ready' is a state-changing write, yet the annotations declare readOnlyHint=true. An agent relying on the annotation would assume this call has no side effects, which is the opposite of what finalizing an upload does. This is a direct description/annotation conflict, so the rubric's score of 1 applies.

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?

Two short sentences, zero filler, with the action front-loaded before the return values. Every clause earns its place.

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 finalization call with an output schema present, the description covers the essential action and even summarizes the return (asset id, width, height), which is not required. The remaining gap is the unstated upload prerequisite and the mis-signalled side-effect profile, not missing return-value documentation.

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?

There is a single parameter with 100% schema description coverage, and the schema already explains that assetId comes from presign_generation_asset. The description adds nothing about the parameter, so the baseline of 3 for fully documented schemas is correct.

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 gives a concrete verb+resource ('Mark a source image or MP4 upload ready') and scopes it to three destination labs (Video Lab, Image Lab, Paint Lab), so an agent knows exactly what state transition it performs. It stops short of naming the sibling it pairs with (presign_generation_asset) in the description text itself, so it is clear but not fully sibling-differentiated.

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?

'Mark ... ready' implies the tool belongs at the end of an upload flow, but the description never states the prerequisite explicitly (that the file must already be uploaded via presign_generation_asset) or when not to call it. The prerequisite only surfaces in the schema's assetId description, so usage is implied rather than stated.

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