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

No annotations are provided, so the description carries the full burden. It discloses that processing runs in the browser, consumes credits at a higher rate than Document/Image/Scanner workspaces, and explains credit packs and Day Pass exclusions. This adds useful behavioral context beyond the basic resize operation, though it does not mention output file specifics or potential limitations.

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 front-loaded with the core purpose in the first sentence, then adds necessary credit/workspace context. While it is slightly long (5 sentences), all sentences contribute meaningful information about cost and access, which is critical for an agent to decide whether to invoke the tool. No fluff.

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 has no parameters and no output schema, the description provides adequate context: what it does, target format, and important pricing/access details. It is complete enough for an agent to know when and why to use it, though it could mention whether audio is preserved or if batch processing is possible.

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?

The input schema has zero parameters, so the baseline is 4. The description does not need to explain any parameters. It correctly focuses on the tool's purpose and constraints rather than nonexistent inputs.

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 clearly states the verb 'Resize' and the resource 'Video' with an explicit target format: 'TikTok 9:16 vertical format (1080×1920)'. This distinguishes it from sibling resize tools like resize_reels, resize_shorts, and resize_square.

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 clearly implies when to use this tool (when you need a TikTok 9:16 vertical video). It also provides context about credit pricing and workspace availability, which helps the agent understand cost implications. However, it does not explicitly name alternatives or state 'use this instead of X', so it lacks explicit exclusion guidance.

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