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

No annotations are provided, so the description carries the full burden for disclosing behavioral traits. It goes beyond a simple operation statement by noting that processing happens in the browser, consumes more credits than other workspaces, and has limited access under certain plans. This provides substantial decision-relevant behavioral information, though it omits details like output handling or file size limits.

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 starts with a concise, front-loaded statement of the tool's purpose, followed by necessary pricing/access details. While the credit and workspace information occupies several sentences, each adds relevant context. It could be tighter, but the structure is clear and not excessive for the information conveyed.

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 simple conversion tool with no parameters and no output schema, the description covers the essential decision points: what it does, where it runs, how much it costs, and access restrictions. It does not explain how the input video is provided (likely via attachment), but this is not critical for a zero-parameter tool. Overall, it is sufficiently complete for an agent to make an informed invocation.

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 baseline for parameter semantics is 4. The description does not need to explain parameters since there are none. It implicitly communicates that the tool takes a WebM video as input and returns MP4, fulfilling the purpose without schema-related gaps.

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 'Convert WebM videos to MP4 format' with a specific verb and resource, and the format conversion is unambiguous. It distinguishes from sibling conversion tools by explicitly naming the WebM source format, making it easy for an agent to select this tool for WebM inputs.

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 provides usage context around credits and workspace restrictions (e.g., 'Day Pass does not include this workspace'), which helps an agent decide when the tool is available. However, it does not explicitly mention alternatives or when to prefer this tool over other video converters, relying instead on the obvious format-specific name.

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