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

The description adds a behavioral detail beyond the annotations by stating it 'Costs credits from the user's Pixly balance.' This is useful context for a mutation-like operation. It does not describe job persistence or return behavior.

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 two concise sentences, front-loaded with the core action and deliverable. Every sentence contributes meaningful information without filler.

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 8 parameters and no output schema, the description covers the primary purpose and cost but omits operational details such as job ID, return format, or async behavior. It is adequate but not fully complete.

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?

With 63% schema description coverage, many parameters (beforeImageUrl, afterImageUrl, revealStyle, videoIntent, etc.) are already documented. The description's 'two frames' loosely maps to the before/after parameters but offers no additional parameter-level meaning or selection guidance.

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 uses a specific verb ('Animate') and names a clear deliverable (a 'social-ready reveal video'). The example 'empty room → staged' and the mention of 'two frames' distinguish it from sibling tools like virtual_staging or day_to_night.

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 example 'empty room → staged' provides a clear use case, and 'from two frames' defines the input requirements. However, it does not explicitly state when not to use it or mention alternative tools.

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