add_watermark

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

With no annotations, the description must disclose behavioral traits but only mentions the basic overlay operation. It does not mention that it creates a new output file, any format requirements, or potential side effects, leaving the agent under-informed about the tool's impact.

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 a single clear sentence with no redundant words. It is efficiently structured and immediately conveys the core operation.

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 complexity of video processing and the absence of output schema and annotations, the description is too sparse. It lacks details on output behavior, supported formats, or any caveats, making it incomplete for an AI agent to fully understand the tool's implications.

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 67%, and the description adds slight context by mentioning position ('corner or the center'), which aligns with the position enum. However, it does not explain other parameters like opacity or scale_width, so it only marginally supplements the schema.

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 action ('Overlay') and resource ('logo/watermark image onto a video'), and specifies position options ('chosen corner or the center'). It distinguishes from sibling add_text_overlay by focusing on an image watermark, though it doesn't explicitly name the alternative.

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?

No guidance is provided on when to use this tool versus alternatives like add_text_overlay. The description simply states what it does without any context on suitable scenarios or exclusions.

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