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

Annotations already cover the safety profile (readOnlyHint false, destructiveHint false), and the description adds genuine value beyond them: it discloses the async contract (returns toolExecutionId, poll via get_tool_execution) and confirms the source file is not modified. It does not discuss rate limits or failure modes, so it falls short of a 5.

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 short sentences, zero filler, with the core purpose front-loaded and the async/return behavior following in priority order.

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 an output schema present and the async follow-up path named explicitly, an agent has everything it needs: what the tool does, what it returns, and how to retrieve the result. The absence of resolution parameters is a tool-design choice, not a description gap.

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% with a single documented parameter, so the schema already explains where videoFileId comes from. The description adds no format or constraint detail beyond it, making the baseline 3 appropriate.

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 ('Create a higher-resolution copy of an existing video') and names the outcome (a new file). This cleanly distinguishes it from upscale_image and the generate_* siblings.

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 implies the use case (you already have a video file to improve) and notes the source is unchanged, but it never states when to prefer this over alternatives or what prerequisites apply. Usage is inferable rather than stated.

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