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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds useful framing around recency and catalog expansion, but it does not disclose how 'recently' is determined or what the returned brand list represents beyond first_seen semantics. The added context is helpful but modest given the annotations already cover the safety profile.

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 tight sentences with the main operation front-loaded. The second sentence earns its place by giving real query examples that help an agent recognize user intent. There is no redundancy or 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?

For an 8-parameter tool with no output schema, the description is sufficient for tool selection and a basic call using the required operator_name. However, it does not explain return shape, default recency behavior, or how optional filters affect results, leaving notable gaps for a parameter-rich tool.

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 description provides no parameter-level guidance. It does not clarify brand_contains, first_seen_from, first_seen_to, or limit, and schema coverage is only 63%, so the description does not compensate for the undocumented parameters. The operator_name parameter is implied by 'this seller' but never explicitly tied to the schema field.

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 specific verb and resource: 'Show brands an operator recently started selling.' It also gives concrete user-query examples. However, it does not explicitly differentiate itself from sibling tools such as operator_lost_brands or operator_top_brands, so it stops short of a perfect score.

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 explicitly lists trigger phrasings and generalizes to 'any question about an operator expanding their catalog,' giving clear when-to-use guidance. It does not state when not to use the tool or mention an alternative sibling, so it lacks the exclusions needed for a 5.

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