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

Annotations already provide readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds the temporal churn concept, reinforced by since_days, but does not disclose details like how the comparison window is computed or how first_seen/last_seen filters interact. This is modest context beyond annotations.

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?

Core behavior is stated in the first sentence and usage guidance in the second. There is no filler or repetition of schema facts, and the query examples are useful for an agent parsing intent quickly.

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 10-parameter tool with no output schema and minimal annotations, the description covers only core intent and query phrasing. It omits how optional filters alter results, the meaning of date-window fields, and what a response looks like, leaving the agent to infer behavior from parameter names and defaults.

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 only 50%, and the description itself mentions no parameter names, defaults, or value formats. Parameters like brand_contains, first_seen_from/to, last_seen_week_to, and limit are undocumented in both the schema and description, and the description does not compensate for this gap.

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 opens with a specific verb-resource pair ('Show brands an operator recently stopped selling') and explicitly labels the result as a churn signal. This clearly distinguishes it from sibling tools such as operator_new_brands or brands_gaining_sellers without needing to inspect schemas.

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 says 'Use when the user asks...' and provides concrete query examples plus a general paraphrase ('any question about an operator shrinking their catalog'). However, it does not name an alternative tool or state when not to use it, so it stops short of full routing guidance.

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