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

Annotations already disclose readOnlyHint=false, openWorldHint=true, idempotentHint=false, and destructiveHint=false, so the agent knows this is a non-destructive, non-idempotent write that may interact with external state. The description adds nothing beyond what the annotations provide, and with annotations carrying the behavioral burden a baseline of 3 is appropriate.

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?

A single short sentence with no waste, front-loading the verb and resource. It is appropriately sized but does not use the available space to add value.

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 two-parameter mutation tool with no output schema, the description omits key context: what a watermark group actually is, the max-50 video constraint already in the schema could be reinforced, and no return behavior is mentioned. With no output schema and no annotations covering creation semantics, more was needed.

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 description coverage is 100%: the schema documents 'name' as 'Group name' and 'video_ids' as 'Videos to include in this group (max 50)'. The description adds no parameter meaning beyond the schema, so the baseline of 3 applies.

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 states a clear verb+resource ('Create a new watermark group'), but it does not distinguish this tool from the sibling 'panda_action_create_watermark_group_for_folder' or clarify the relationship to folder-scoped creation. It restates the title almost verbatim, adding little beyond what the name conveys.

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 such as 'panda_action_create_watermark_group_for_folder'. It does not specify prerequisites (e.g., whether videos must exist beforehand) or the context in which a standalone watermark group is appropriate.

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